Merge branch 'main' into osnr/vulkan-display

39 files changed, 2565 insertions, 559 deletions

diff --git a/Makefile b/Makefile
index 9c5c1528..6f5fce0b 100644
--- a/Makefile
+++ b/Makefile
@@ -38,8 +38,10 @@ flamegraph:
 	~/FlameGraph/stackcollapse-perf.pl out.perf > out.folded
 	~/FlameGraph/flamegraph.pl out.folded > out.svg
 
+# You can use the Web server to check the pid of display.folk,
+# apriltags.folk, camera.folk, etc.
 remote-flamegraph:
-	ssh -t folk@$(FOLK_SHARE_NODE) -- make -C /home/folk/folk flamegraph
+	ssh -t folk@$(FOLK_SHARE_NODE) -- make -C /home/folk/folk flamegraph $(if $(REMOTE_FLAMEGRAPH_TID),FLAMEGRAPH_TID=$(REMOTE_FLAMEGRAPH_TID),)
 	scp folk@$(FOLK_SHARE_NODE):~/folk/out.svg .
 	scp folk@$(FOLK_SHARE_NODE):~/folk/out.perf .
 
diff --git a/README.md b/README.md
index 65dd409d..6ce006fb 100644
--- a/README.md
+++ b/README.md
@@ -452,6 +452,26 @@ retrigger, and so on.
 in its body will run again unless the boop goes away and an entirely
 new boop appears.
 
+### Animation
+
+#### Getting time
+
+Get the global clock time with:
+
+```
+When the clock time is /t/ {
+  Wish $this is labelled $t
+}
+```
+
+Use it in an animation:
+
+```
+When the clock time is /t/ {
+  Wish $this draws a circle offset [list [expr {sin($t) * 50}] 0]
+}
+```
+
 ### You usually won't need these
 
 #### When when
diff --git a/calibrate.tcl b/calibrate.tcl
index cf2471f4..48cf0b8e 100644
--- a/calibrate.tcl
+++ b/calibrate.tcl
@@ -1,3 +1,4 @@
+source "lib/language.tcl"
 source "lib/c.tcl"
 
 exec sudo systemctl stop folk
diff --git a/hosts.tcl b/hosts.tcl
index 7bc292e6..26f1b6c3 100644
--- a/hosts.tcl
+++ b/hosts.tcl
@@ -34,8 +34,10 @@ if {[info exists ::env(FOLK_SHARE_NODE)]} {
             set ::shareNode "folk-arc.local"
         } elseif {$wifi eq "The Windfish"} {
             set ::shareNode "folk-dpip.local"
-        } elseif {$wifi eq "Moxie"} {
+        } elseif {$wifi eq "interact residency"} {
             set ::shareNode "folk-interact.local"
+        } elseif {$wifi eq "Fios-gLwY5" } {
+            set ::shareNode "folk-charles.local"
         } else {
             # there's no default.
         }
diff --git a/laptop.tcl b/laptop.tcl
index c58dbb1f..6a640460 100644
--- a/laptop.tcl
+++ b/laptop.tcl
@@ -47,7 +47,7 @@ namespace eval Display {
         uplevel [list Wish display runs [list .display create line {*}[join $points] -fill $color -width $width]]
     }
 
-    proc text {fb x y scale text {radians 0}} {
+    proc text {x y scale text {radians 0}} {
         uplevel [list Wish display runs [list .display create text $x $y -text $text -font "Helvetica [expr {$scale * 12}]" -fill white -anchor center -angle [expr {$radians/3.14159*180}]]]
     }
 
diff --git a/lib/environment.tcl b/lib/environment.tcl
index 28dd33fb..6a83802e 100644
--- a/lib/environment.tcl
+++ b/lib/environment.tcl
@@ -19,20 +19,21 @@ proc runInSerializedEnvironment {lambda env} {
     if {![dict exists $::Evaluator::totalTimesMap $lambda]} {
         dict set ::Evaluator::totalTimesMap $lambda [dict create loadTime 0 runTime 0 unloadTime 0]
     }
-    set loadTime_ [time {}]
+    set loadTime_ [baretime {}]
 
     try {
-        set runTime_ [time {set ret [apply $lambda {*}$env]}]
+        set runTime_ [baretime {set ret [apply $lambda {*}$env]}]
+        set ::stepRunTime [+ $::stepRunTime $runTime_]
         set ret
 
     } finally {
-        set unloadTime_ [time {}]
+        set unloadTime_ [baretime {}]
         dict with ::Evaluator::totalTimesMap $lambda {
-            incr loadTime [string map {" microseconds per iteration" ""} $loadTime_]
+            incr loadTime $loadTime_
             if {[info exists runTime_]} {
-                incr runTime [string map {" microseconds per iteration" ""} $runTime_]
+                incr runTime $runTime_
             }
-            incr unloadTime [string map {" microseconds per iteration" ""} $unloadTime_]
+            incr unloadTime $unloadTime_
         }
     }
 }
diff --git a/lib/evaluator.tcl b/lib/evaluator.tcl
index a411169d..daff44b3 100644
--- a/lib/evaluator.tcl
+++ b/lib/evaluator.tcl
@@ -749,6 +749,15 @@ namespace eval Statements { ;# singleton Statement store
         }
         return "digraph { rankdir=LR; [join $dot "\n"] }"
     }
+    proc saveDotToPdf {filename} {
+        exec dot -Tpdf >$filename <<[Statements::dot]
+    }
+
+    proc print {} {
+        dict for {id stmt} [Statements::all] {
+            puts [statement short $stmt]
+        }
+    }
 
     # these are kind of arbitrary/temporary bridge
     $cc proc matchRemoveFirstDestructor {match_handle_t matchId} void {
@@ -875,6 +884,7 @@ namespace eval Evaluator {
             }
         }
         static void LogWriteRecollect(statement_handle_t collectId);
+        static void LogWriteUnmatch(match_handle_t matchId);
         void reactToStatementAdditionThatMatchesCollect(Tcl_Interp* interp,
                                                         statement_handle_t collectId,
                                                         Tcl_Obj* collectPattern,
@@ -1000,8 +1010,7 @@ namespace eval Evaluator {
                 match_handle_t matchId = edge->match;
                 if (!matchExists(matchId)) continue; // if was removed earlier
 
-                reactToMatchRemoval(interp, matchId);
-                matchRemove(matchId);
+                LogWriteUnmatch(matchId);
             }
         }
     }
@@ -1014,6 +1023,7 @@ namespace eval Evaluator {
                 if (unmatch->edges[j].type == PARENT) {
                     statement_handle_t unmatchWhenId = unmatch->edges[j].statement;
                     statement_t* unmatchWhen = get(unmatchWhenId);
+                    if (unmatchWhen == NULL) continue;
                     for (int k = 0; k < unmatchWhen->n_edges; k++) {
                         if (unmatchWhen->edges[k].type == PARENT) {
                             unmatchId = unmatchWhen->edges[k].match;
@@ -1093,8 +1103,7 @@ namespace eval Evaluator {
                 if (edge->type == CHILD && !matchHandleIsEqual(edge->match, matchId)) {
                     match_handle_t childMatchId = edge->match;
                     matchGet(childMatchId)->recollectOnDestruction = false;
-                    reactToMatchRemoval(interp, childMatchId);
-                    matchRemove(childMatchId);
+                    LogWriteUnmatch(childMatchId);
                     break;
                 }
             }
@@ -1103,7 +1112,7 @@ namespace eval Evaluator {
 
     $cc code {
         typedef enum {
-            NONE, ASSERT, RETRACT, SAY, RECOLLECT
+            NONE, ASSERT, RETRACT, SAY, UNMATCH, RECOLLECT
         } log_entry_op_t;
         typedef struct log_entry_t {
             log_entry_op_t op;
@@ -1114,21 +1123,24 @@ namespace eval Evaluator {
                     match_handle_t parentMatchId;
                     Tcl_Obj* clause;
                 } say;
+                struct { match_handle_t matchId; } unmatch;
                 struct { statement_handle_t collectId; } recollect;
             };
         } log_entry_t;
 
-        log_entry_t evaluatorLog[1024] = {0};
+        log_entry_t evaluatorLog[4096] = {0};
         #define EVALUATOR_LOG_CAPACITY (sizeof(evaluatorLog)/sizeof(evaluatorLog[1]))
         int evaluatorLogReadIndex = EVALUATOR_LOG_CAPACITY - 1;
         int evaluatorLogWriteIndex = 0;
     }
     $cc proc Evaluate {Tcl_Interp* interp} void {
+        /* printf("Evaluate==========\n"); */
         while (evaluatorLogReadIndex != evaluatorLogWriteIndex) {
             log_entry_t entry = evaluatorLog[evaluatorLogReadIndex];
             evaluatorLogReadIndex = (evaluatorLogReadIndex + 1) % EVALUATOR_LOG_CAPACITY;
 
             if (entry.op == ASSERT) {
+                /* printf("Assert (%s)\n", Tcl_GetString(entry.assert.clause)); */
                 statement_handle_t id; bool isNewStatement;
                 addImpl(interp, entry.assert.clause, 0, NULL,
                         &id, &isNewStatement);
@@ -1138,6 +1150,7 @@ namespace eval Evaluator {
                 Tcl_DecrRefCount(entry.assert.clause);
 
             } else if (entry.op == RETRACT) {
+                /* printf("Retract (%s)\n", Tcl_GetString(entry.retract.pattern)); */
                 environment_t* results[1000];
                 int resultsCount = searchByPattern(entry.retract.pattern,
                                                    1000, results);
@@ -1150,6 +1163,7 @@ namespace eval Evaluator {
                 Tcl_DecrRefCount(entry.retract.pattern);
 
             } else if (entry.op == SAY) {
+                /* printf("Say (%s)\n", Tcl_GetString(entry.say.clause)); */
                 if (matchExists(entry.say.parentMatchId)) {
                     statement_handle_t id; bool isNewStatement;
                     addImpl(interp, entry.say.clause, 1, &entry.say.parentMatchId,
@@ -1160,7 +1174,15 @@ namespace eval Evaluator {
                 }
                 Tcl_DecrRefCount(entry.say.clause);
 
+            } else if (entry.op == UNMATCH) {
+                /* printf("Unmatch (m%d:%d)\n", entry.unmatch.matchId.idx, entry.unmatch.matchId.gen); */
+                if (matchExists(entry.unmatch.matchId)) {
+                    reactToMatchRemoval(interp, entry.unmatch.matchId);
+                    matchRemove(entry.unmatch.matchId);
+                }
+
             } else if (entry.op == RECOLLECT) {
+                /* printf("Recollect (s%d:%d)\n", entry.recollect.collectId.idx, entry.recollect.collectId.gen); */
                 if (exists(entry.recollect.collectId)) {
                     recollect(interp, entry.recollect.collectId);
                 }
@@ -1191,8 +1213,11 @@ namespace eval Evaluator {
         Tcl_IncrRefCount(clause);
         LogWriteFront((log_entry_t) { .op = SAY, .say = {.parentMatchId=parentMatchId, .clause=clause} });
     }
+    $cc proc LogWriteUnmatch {match_handle_t matchId} void {
+        LogWriteBack((log_entry_t) { .op = UNMATCH, .unmatch = {.matchId=matchId} });
+    }
     $cc proc LogWriteRecollect {statement_handle_t collectId} void {
-        LogWriteBack((log_entry_t) { .op = RECOLLECT, .recollect = {.collectId=collectId} });
+        LogWriteFront((log_entry_t) { .op = RECOLLECT, .recollect = {.collectId=collectId} });
     }
     $cc proc LogIsEmpty {} bool {
         return evaluatorLogReadIndex == evaluatorLogWriteIndex;
diff --git a/lib/language.tcl b/lib/language.tcl
index b265b5a6..2b9fbc01 100644
--- a/lib/language.tcl
+++ b/lib/language.tcl
@@ -70,6 +70,8 @@ proc assert condition {
     }
 }
 
+proc baretime body { string map {" microseconds per iteration" ""} [uplevel [list time $body]] }
+
 # forever { ... } is sort of like while true { ... }, but it yields to
 # the event loop after each iteration.
 proc forever {body} {
diff --git a/lib/math.tcl b/lib/math.tcl
index 9fc6839a..23efc57b 100644
--- a/lib/math.tcl
+++ b/lib/math.tcl
@@ -139,6 +139,18 @@ namespace eval ::region {
         set bottomEdgeIndex [lindex [lsort -indices -real -index 1 $edgeMidpoints] end]
         vec2 midpoint {*}[edgeToLineSegment $r [lindex [edges $r] $bottomEdgeIndex]]
     }
+    proc bottomleft {r} {
+      lindex [vertices $r] 0
+    }
+    proc bottomright {r} {
+      lindex [vertices $r] 1
+    }
+    proc topright {r} {
+      lindex [vertices $r] 2
+    }
+    proc topleft {r} {
+      lindex [vertices $r] 3
+    }
 
     proc mapVertices {varname r body} {
         lreplace $r 0 0 [uplevel [list lmap $varname [vertices $r] $body]]
@@ -262,7 +274,7 @@ namespace eval ::region {
                 error "region move: Invalid distance $distance"
             }
             if {$unit eq "%"} {
-                set distance [* distance 0.01]
+                set distance [* $distance 0.01]
                 set unit ""
             }
             if {$unit eq ""} {
diff --git a/lib/peer.tcl b/lib/peer.tcl
index 274f9f07..ef8e1e1c 100644
--- a/lib/peer.tcl
+++ b/lib/peer.tcl
@@ -24,73 +24,64 @@ namespace eval clauseset {
 namespace eval ::Peers {}
 set ::peersBlacklist [dict create]
 
+proc ::addMatchesToShareStatements {shareStatementsVar matches} {
+    upvar $shareStatementsVar shareStatements
+    foreach m $matches {
+        set pattern [dict get $m pattern]
+        foreach match [Statements::findMatches $pattern] {
+            set id [lindex [dict get $match __matcheeIds] 0]
+            set clause [statement clause [Statements::get $id]]
+            clauseset add shareStatements $clause
+        }
+    }
+}
+
 proc ::peer {process {dieOnDisconnect false}} {
-    package require websocket
     namespace eval ::Peers::$process {
-        variable connected false
+        variable connected true
 
         proc log {s} {
             variable process
             puts "$::thisProcess -> $process: $s"
         }
-        proc setupSock {} {
+
+        # TODO: Handle die on disconnect (?)
+
+        proc send {statements} {
             variable process
-            log "Trying to connect to: ws://$process:4273/ws"
-            variable chan [::websocket::open "ws://$process:4273/ws" [namespace code handleWs]]
+            Mailbox::share $::thisProcess $process $statements
         }
-        proc handleWs {chan type msg} {
-            if {$type eq "connect"} {
-                log "Connected"
-                variable connected true
-
-                # Establish a peering on their end, in the reverse
-                # direction, so they can send stuff back to us.
-                # It'll implicitly run in a ::Peers::X namespace on their end
-                # (because of how `run` is implemented below)
-                run {
-                    set name [namespace tail [namespace current]]
-                    variable chan [uplevel {set chan}]
-
-                    # First, check if this side has us blacklisted.
-                    if {[dict exists $::peersBlacklist $name]} {
-                        ::websocket::close $chan
-                        return
-                    }
-
-                    variable connected true
-                    proc run {msg} {
-                        variable chan
-                        ::websocket::send $chan text $msg
-                    }
-                }
-            } elseif {$type eq "disconnect"} {
-                log "Disconnected"
-
-                variable dieOnDisconnect
-                if {$dieOnDisconnect} { exit 0 }
-
-                variable connected false
-                after 2000 [namespace code setupSock]
-            } elseif {$type eq "error"} {
-                log "WebSocket error: $type $msg"
-                after 2000 [namespace code setupSock]
-            } elseif {$type eq "text"} {
-                eval $msg
-            } elseif {$type eq "ping" || $type eq "pong"} {
-            } else {
-                error "Unknown WebSocket event: $type $msg"
-            }
+        proc receive {} {
+            variable process
+            Mailbox::receive $process $::thisProcess
         }
 
-        proc run {msg} {
-            variable chan
-            ::websocket::send $chan text [list namespace eval ::Peers::$::thisProcess $msg]
+        proc share {shareStatements} {
+            variable process
+            variable prevShareStatements
+
+            variable connected
+            if {!$connected} { return }
+
+            # Share.
+            ::addMatchesToShareStatements shareStatements \
+                [Statements::findMatches [list /someone/ wishes $process receives statements like /pattern/]]
+            if {![info exists prevShareStatements] ||
+                ([clauseset size $prevShareStatements] > 0 ||
+                 [clauseset size $shareStatements] > 0)} {
+
+                send [clauseset clauses $shareStatements]
+
+                set prevShareStatements $shareStatements
+            }
         }
 
         proc init {n shouldDieOnDisconnect} {
-            variable process $n; setupSock
+            variable process $n
             variable dieOnDisconnect $shouldDieOnDisconnect
-            vwait ::Peers::${n}::connected
+
+            Mailbox::create $::thisProcess $process
+            Mailbox::create $process $::thisProcess
         }
         init
     } $process $dieOnDisconnect
diff --git a/lib/process.tcl b/lib/process.tcl
index a4b8ed48..059c0b89 100644
--- a/lib/process.tcl
+++ b/lib/process.tcl
@@ -58,19 +58,22 @@ namespace eval ::Zygote {
 
 proc On-process {name body} {
     set this [uplevel {expr {[info exists this] ? $this : "<unknown>"}}]
-    set processCode [list apply {{__name __body} {
+    set processCode [list apply {{__parentProcess __name __body} {
         set ::thisProcess $__name
 
         Assert <lib/process.tcl> wishes $::thisProcess shares all wishes
         Assert <lib/process.tcl> wishes $::thisProcess shares all claims
 
-        ::peer "localhost" true
+        ::peer $__parentProcess true
 
         Assert <lib/process.tcl> claims $::thisProcess has pid [pid]
         Assert when $::thisProcess has pid /something/ [list {} $__body]
-        Step
-        vwait forever
-    }} $name $body]
+        while true {
+            Step
+        }
+    }} $::thisProcess $name $body]
+
+    ::peer $name false
 
     Zygote::spawn [list apply {{processCode} {
         # A supervisor that wraps the subprocess.
diff --git a/lib/terminal.tcl b/lib/terminal.tcl
new file mode 100644
index 00000000..16e553ca
--- /dev/null
+++ b/lib/terminal.tcl
@@ -0,0 +1,193 @@
+# terminal.tcl --
+#
+#     Implements a virtual terminal with basic read/write procs.
+#
+
+namespace eval Terminal {
+  # From `man console_codes`
+  variable keymap [dict create \
+    BACKSPACE "\x08" \
+    TAB       "\x09" \
+    ENTER     "\x0d" \
+    DELETE    "\x7f" \
+    ESC       "\x1b" \
+    UP        "\x1b\[A" \
+    DOWN      "\x1b\[B" \
+    RIGHT     "\x1b\[C" \
+    LEFT      "\x1b\[D" \
+  ]
+
+  proc _remap {key ctrlPressed} {
+    variable keymap
+    if {[string length $key] == 1} {
+      # Convert ctrl-A through ctrl-Z and others to terminal control characters
+      if {$ctrlPressed} {
+        set charCode [scan [string toupper $key] %c]
+        if {$charCode >= 64 && $charCode <= 95} {
+          set charCode [expr {$charCode - 64}]
+          return [format %c $charCode]
+        }
+      }
+      # All other single char keys can be passed through
+      return $key
+    }
+    if {[dict exists $keymap $key]} {
+      return [dict get $keymap $key]
+    }
+    return ""
+  }
+
+  proc create {rows cols cmd} {
+    termCreate $rows $cols [list bash -c $cmd ""]
+  }
+
+  proc destroy {term} {
+    termDestroy $term
+  }
+
+  # Writes a keyboard key to the terminal, handling control codes
+  proc write {term key ctrlPressed} {
+    set key [_remap $key $ctrlPressed]
+    if {[string length $key] > 0} {
+      termWrite $term $key
+    }
+  }
+
+  # Returns a newline separated string of terminal lines
+  proc read {term} {
+    termRead $term
+  }
+}
+
+set cc [c create]
+$cc cflags -I./vendor/libtmt ./vendor/libtmt/tmt.c
+
+c loadlib [lindex [exec /usr/sbin/ldconfig -p | grep libutil.so | head -1] end]
+$cc cflags -lutil
+
+$cc include <sys/types.h>
+$cc include <stdlib.h>
+$cc include <unistd.h>
+$cc include <pty.h>
+$cc include <fcntl.h>
+$cc include <string.h>
+$cc include <sys/time.h>
+$cc include <signal.h>
+$cc include "tmt.h"
+
+$cc struct VTerminal {
+  TMT* tmt;
+  int pty_fd;
+  int pid;
+
+  // Note: display has 1 more column than tmt screen to hold newlines between each line
+  char* display;
+  int curs_r;
+  int curs_c;
+  int ncols;
+};
+
+$cc code {
+  #define PTYBUF 4096
+  char iobuf[PTYBUF];
+
+  char* charAt(VTerminal *vt, int r, int c) {
+    int i = r * (vt->ncols + 1) + c;
+    return &vt->display[i];
+  }
+
+  void tmtEvent(tmt_msg_t m, TMT *tmt, const void *a, void *p) {
+      VTerminal *vt = (VTerminal*)p;
+      const TMTSCREEN *s = tmt_screen(tmt);
+
+      if (m == TMT_MSG_UPDATE) {
+        for (size_t r = 0; r < s->nline; r++){
+            if (s->lines[r]->dirty){
+                for (size_t c = 0; c < s->ncol; c++){
+                  *charAt(vt, r, c) = s->lines[r]->chars[c].c;
+                }
+            }
+        }
+        tmt_clean(tmt);
+      }
+  }
+
+  void blinkCursor(VTerminal *vt) {
+    // Restore char under old cursor
+    const TMTSCREEN *s = tmt_screen(vt->tmt);
+    *charAt(vt, vt->curs_r, vt->curs_c) = s->lines[vt->curs_r]->chars[vt->curs_c].c;
+
+    // Update new cursor
+    const TMTPOINT *c = tmt_cursor(vt->tmt);
+    vt->curs_r = c->r;
+    vt->curs_c = c->c;
+
+    // Replace char with cursor every other second
+    struct timeval tv;
+    gettimeofday(&tv, NULL);
+    if (tv.tv_sec % 2 == 0) {
+      *charAt(vt, vt->curs_r, vt->curs_c) = 0xDB; // block char: █
+    }
+  }
+}
+
+$cc proc termCreate {int rows int cols char* cmd[]} VTerminal* {
+  int i = 0;
+  while (true) {
+    // execvp requires cmd array to be terminated by null pointer
+    if (strlen(cmd[i]) == 0) { cmd[i] = NULL; break; }
+    i++;
+  }
+
+  VTerminal *vt = malloc(sizeof(VTerminal));
+  vt->curs_r = 0;
+  vt->curs_c = 0;
+  vt->ncols = cols;
+
+  vt->display = malloc(sizeof(char[rows][cols + 1]));
+  for (int r = 0; r < rows - 1; r++) {
+    *charAt(vt, r, cols) = '\n';
+  }
+  *charAt(vt, rows - 1, cols) = '\0';
+
+  vt->tmt = tmt_open(rows, cols, tmtEvent, vt, NULL);
+
+  struct winsize ws = {.ws_row = rows, .ws_col = cols};
+  pid_t pid = forkpty(&vt->pty_fd, NULL, NULL, &ws);
+  if (pid < 0){
+    return NULL;
+  } else if (pid == 0){
+    setenv("TERM", "ansi", 1);
+    if (execvp(cmd[0], cmd) == -1) {
+      fprintf(stderr, "execvp(%s, ...) failed: %m\n", cmd[0]);
+    }
+    return NULL;
+  }
+
+  vt->pid = pid;
+  fcntl(vt->pty_fd, F_SETFL, O_NONBLOCK);
+  return vt;
+}
+
+$cc proc termDestroy {VTerminal* vt} void {
+  kill(vt->pid, SIGTERM);
+  close(vt->pty_fd);
+  free(vt->display);
+  free(vt);
+}
+
+$cc proc termRead {VTerminal* vt} char* {
+  ssize_t r = read(vt->pty_fd, iobuf, PTYBUF);
+  if (r > 0) {
+    tmt_write(vt->tmt, iobuf, r);
+  }
+
+  blinkCursor(vt);
+  return vt->display;
+}
+
+$cc proc termWrite {VTerminal* vt char* key} void {
+  write(vt->pty_fd, key, strlen(key));
+}
+
+$cc compile
diff --git a/lib/trie.tcl b/lib/trie.tcl
index e5c2c0be..1f9bac8d 100644
--- a/lib/trie.tcl
+++ b/lib/trie.tcl
@@ -33,8 +33,8 @@ namespace eval ctrie {
 
             // We generally store a pointer (for example, to a
             // reaction thunk) or a generational handle (for example,
-            // for a statement) in this 64-bit value slot. Only used
-            // in leaf nodes of the trie.
+            // for a statement) in this 64-bit value slot.
+            bool hasValue;
             uint64_t value;
 
             size_t nbranches;
@@ -47,6 +47,7 @@ namespace eval ctrie {
         trie_t* ret = (trie_t *) ckalloc(size); memset(ret, 0, size);
         *ret = (trie_t) {
             .key = NULL,
+            .hasValue = false,
             .value = 0,
             .nbranches = 10
         };
@@ -83,6 +84,7 @@ namespace eval ctrie {
     $cc proc addImpl {trie_t** trie int wordc Tcl_Obj** wordv uint64_t value} void {
         if (wordc == 0) {
             (*trie)->value = value;
+            (*trie)->hasValue = true;
             return;
         }
 
@@ -116,6 +118,7 @@ namespace eval ctrie {
             branch->key = word;
             Tcl_IncrRefCount(branch->key);
             branch->value = 0;
+            branch->hasValue = false;
             branch->nbranches = 10;
 
             (*trie)->branches[j] = branch;
@@ -178,7 +181,7 @@ namespace eval ctrie {
                          uint64_t* results int* resultsidx size_t maxresults
                          trie_t* trie int wordc Tcl_Obj** wordv} void {
         if (wordc == 0) {
-            if (trie->value != 0) {
+            if (trie->hasValue) {
                 if (*resultsidx < maxresults) {
                     results[(*resultsidx)++] = trie->value;
                 }
diff --git a/main.tcl b/main.tcl
index d00deb1a..2f95fe25 100644
--- a/main.tcl
+++ b/main.tcl
@@ -1,5 +1,14 @@
 if {$tcl_version eq 8.5} { error "Don't use Tcl 8.5 / macOS system Tcl. Quitting." }
 
+# TODO: Fix this hack.
+set thisPid [pid]
+foreach pid [try { exec pgrep tclsh8.6 } on error e { list }] {
+    if {$pid ne $thisPid} {
+        exec kill -9 $pid
+    }
+}
+exec sleep 1
+
 if {[info exists ::argv0] && $::argv0 eq [info script]} {
     set ::isLaptop [expr {$tcl_platform(os) eq "Darwin" ||
                           ([info exists ::env(XDG_SESSION_TYPE)] &&
@@ -133,6 +142,7 @@ proc On {event args} {
         # send that to the subprocess.
         lassign [uplevel Evaluator::serializeEnvironment] argNames argValues
         uplevel [list On-process $name [list apply [list $argNames $body] {*}$argValues]]
+        set name ;# Return the name to the caller in case they want it.
 
     } elseif {$event eq "unmatch"} {
         set body [lindex $args 0]
@@ -156,8 +166,9 @@ proc After {n unit body} {
 set ::committed [dict create]
 set ::toCommit [dict create]
 proc Commit {args} {
+    upvar this this
     set body [lindex $args end]
-    set key [list Commit [uplevel {expr {[info exists this] ? $this : "<unknown>"}}] {*}[lreplace $args end end]]
+    set key [list Commit [expr {[info exists this] ? $this : "<unknown>"}] {*}[lreplace $args end end]]
     if {$body eq ""} {
         dict set ::toCommit $key $body
     } else {
@@ -165,18 +176,22 @@ proc Commit {args} {
         set lambda [list {this} [list apply [list $argNames $body] {*}$argValues]]
         dict set ::toCommit $key $lambda
     }
-
-    after idle Step
 }
 
 set ::stepCount 0
-set ::stepTime "none"
+set ::stepTime -1
 source "lib/peer.tcl"
 proc StepImpl {} {
     incr ::stepCount
     Assert $::thisProcess has step count $::stepCount
     Retract $::thisProcess has step count [expr {$::stepCount - 1}]
 
+    # Receive statements from all peers.
+    foreach peerNs [namespace children ::Peers] {
+        upvar ${peerNs}::process peer
+        Commit $peer [list Say $peer is sharing statements [${peerNs}::receive]]
+    }
+
     while {[dict size $::toCommit] > 0 || ![Evaluator::LogIsEmpty]} {
         dict for {key lambda} $::toCommit {
             if {$lambda ne ""} {
@@ -193,65 +208,44 @@ proc StepImpl {} {
         Evaluator::Evaluate
     }
 
-    if {[namespace exists Display]} {
-        Display::commit ;# TODO: this is weird, not right level
-    }
-
-    set shareStatements [clauseset create]
-    set shareAllWishes [expr {[llength [Statements::findMatches [list /someone/ wishes $::thisProcess shares all wishes]]] > 0}]
-    set shareAllClaims [expr {[llength [Statements::findMatches [list /someone/ wishes $::thisProcess shares all claims]]] > 0}]
-    dict for {_ stmt} [Statements::all] {
-        if {($shareAllWishes && [lindex [statement clause $stmt] 1] eq "wishes") ||
-            ($shareAllClaims && [lindex [statement clause $stmt] 1] eq "claims")} {
-            clauseset add shareStatements [statement clause $stmt]
-        }
-    }
-
-    set matches [Statements::findMatches [list /someone/ wishes $::thisProcess shares statements like /pattern/]]
-    proc ::addMatchesToShareStatements {shareStatementsVar matches} {
-        upvar $shareStatementsVar shareStatements
-        foreach m $matches {
-            set pattern [dict get $m pattern]
-            foreach match [Statements::findMatches $pattern] {
-                set id [lindex [dict get $match __matcheeIds] 0]
-                set clause [statement clause [Statements::get $id]]
-                clauseset add shareStatements $clause
+    # Share statements to all peers.
+    set ::peerTime [baretime {
+        # This takes 2 ms.
+        set shareStatements [clauseset create]
+        set shareAllWishes [expr {[llength [Statements::findMatches [list /someone/ wishes $::thisProcess shares all wishes]]] > 0}]
+        set shareAllClaims [expr {[llength [Statements::findMatches [list /someone/ wishes $::thisProcess shares all claims]]] > 0}]
+        dict for {_ stmt} [Statements::all] {
+            if {($shareAllWishes && [lindex [statement clause $stmt] 1] eq "wishes") ||
+                ($shareAllClaims && [lindex [statement clause $stmt] 1] eq "claims")} {
+                clauseset add shareStatements [statement clause $stmt]
             }
         }
-    }
-    ::addMatchesToShareStatements shareStatements $matches
-
-    foreach peerNs [namespace children ::Peers] {
-        apply [list {peer shareStatements} {
-            variable prevShareStatements
-
-            variable connected
-            if {!$connected} { return }
-
-            ::addMatchesToShareStatements shareStatements \
-                [Statements::findMatches [list /someone/ wishes $peer receives statements like /pattern/]]
 
-            if {![info exists prevShareStatements] ||
-                ([clauseset size $prevShareStatements] > 0 ||
-                 [clauseset size $shareStatements] > 0)} {
+        set matches [Statements::findMatches [list /someone/ wishes $::thisProcess shares statements like /pattern/]]
+        ::addMatchesToShareStatements shareStatements $matches
 
-                run [list apply {{process receivedStatements} {
-                    upvar chan chan
-                    Commit $chan statements {
-                        Claim $process is sharing statements $receivedStatements
-                    }
-                }} $::thisProcess [clauseset clauses $shareStatements]]
-
-                set prevShareStatements $shareStatements
-            }
-
-        } $peerNs] [namespace tail $peerNs] $shareStatements
-    }
+        foreach peerNs [namespace children ::Peers] {
+            ${peerNs}::share $shareStatements
+        }
+    }]
 }
+
+set ::frames [list]
 proc Step {} {
-    if {[dict size $::toCommit] > 0 || ![Evaluator::LogIsEmpty]} {
-        set ::stepTime [time StepImpl]
+    set ::stepRunTime 0
+    set stepTime [baretime StepImpl]
+    
+    set framesInLastSecond 0
+    set now [clock milliseconds]
+    lappend ::frames $now
+    foreach frame $::frames {
+        if {$frame > $now - 1000} {
+            incr framesInLastSecond
+        }
     }
+    set ::frames [lreplace $::frames 0 end-$framesInLastSecond]
+
+    set ::stepTime "$stepTime us (peer $::peerTime us, run $::stepRunTime us) ($framesInLastSecond fps)"
 }
 
 source "lib/math.tcl"
@@ -288,30 +282,35 @@ namespace eval ::Heap {
         $cc include <fcntl.h>
         $cc include <unistd.h>
         $cc include <stdlib.h>
+        $cc include <string.h>
+        $cc include <errno.h>
         $cc code {
-            size_t folkHeapSize = 100000000; // 100MB
+            size_t folkHeapSize = 400000000; // 400MB
             uint8_t* folkHeapBase;
-            uint8_t* _Atomic folkHeapPointer;
+            uint8_t** _Atomic folkHeapPointer;
         }
         # The memory mapping of the heap will be inherited by all
         # subprocesses, since it's established before the creation of
         # the zygote.
         $cc proc folkHeapMount {} void {
+            shm_unlink("/folk-heap");
             int fd = shm_open("/folk-heap", O_RDWR | O_CREAT, S_IROTH | S_IWOTH | S_IRUSR | S_IWUSR);
-            ftruncate(fd, folkHeapSize);
+            if (fd == -1) { fprintf(stderr, "folkHeapMount: shm_open failed\n"); exit(1); }
+            if (ftruncate(fd, folkHeapSize) == -1) { fprintf(stderr, "folkHeapMount: ftruncate failed\n"); exit(1); }
             folkHeapBase = (uint8_t*) mmap(0, folkHeapSize,
                                            PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
-            if (folkHeapBase == NULL) {
-                fprintf(stderr, "heapMount: failed"); exit(1);
+            if (folkHeapBase == NULL || folkHeapBase == (void *) -1) {
+                fprintf(stderr, "folkHeapMount: mmap failed: '%s'\n", strerror(errno)); exit(1);
             }
-            folkHeapPointer = folkHeapBase;
+            folkHeapPointer = (uint8_t**) folkHeapBase;
+            *folkHeapPointer = folkHeapBase + sizeof(*folkHeapPointer);
         }
         $cc proc folkHeapAlloc {size_t sz} void* {
-            if (folkHeapPointer + sz > folkHeapBase + folkHeapSize) {
-                fprintf(stderr, "heapAlloc: out of memory"); exit(1);
+            if (*folkHeapPointer + sz >= folkHeapBase + folkHeapSize) {
+                fprintf(stderr, "folkHeapAlloc: out of memory\n"); exit(1);
             }
-            void* ptr = folkHeapPointer;
-            folkHeapPointer = folkHeapPointer + sz;
+            void* ptr = *folkHeapPointer;
+            *folkHeapPointer += sz;
             return (void*) ptr;
         }
         if {$::tcl_platform(os) eq "Linux"} {
@@ -324,6 +323,90 @@ namespace eval ::Heap {
 }
 Heap::init
 
+namespace eval ::Mailbox {
+    set cc [c create]
+    $cc include <stdlib.h>
+    $cc include <string.h>
+    $cc include <pthread.h>
+    $cc import ::Heap::cc folkHeapAlloc as folkHeapAlloc
+    $cc code {
+        typedef struct mailbox_t {
+            bool active;
+
+            pthread_mutex_t mutex;
+
+            char from[100];
+            char to[100];
+
+            int mailLen;
+            char mail[1000000];
+        } mailbox_t;
+
+        #define NMAILBOXES 100
+        mailbox_t* mailboxes;
+    }
+    $cc proc init {} void {
+        fprintf(stderr, "Before: mailboxes = %p\n", mailboxes);
+        mailboxes = folkHeapAlloc(sizeof(mailbox_t) * NMAILBOXES);
+        memset(mailboxes, 0, sizeof(mailbox_t) * NMAILBOXES);
+        fprintf(stderr, "After: mailboxes = %p\n", mailboxes);
+    }
+    $cc proc create {char* from char* to} void {
+        if (find(from, to) != NULL) return;
+        fprintf(stderr, "Mailbox create %s -> %s\n", from, to);
+        for (int i = 0; i < NMAILBOXES; i++) {
+            if (!mailboxes[i].active) {
+                mailboxes[i].active = true;
+                
+                pthread_mutexattr_t mattr;
+                pthread_mutexattr_init(&mattr);
+                pthread_mutexattr_setpshared(&mattr, PTHREAD_PROCESS_SHARED);
+                pthread_mutex_init(&mailboxes[i].mutex, &mattr);
+
+                snprintf(mailboxes[i].from, 100, "%s", from);
+                snprintf(mailboxes[i].to, 100, "%s", to);
+                mailboxes[i].mail[0] = '\0';
+                return;
+            }
+        }
+        fprintf(stderr, "Out of available mailboxes.\n");
+        exit(1);
+    }
+    $cc code {
+        mailbox_t* find(char* from, char* to) {
+            for (int i = 0; i < NMAILBOXES; i++) {
+                if (mailboxes[i].active &&
+                    strcmp(mailboxes[i].from, from) == 0 &&
+                    strcmp(mailboxes[i].to, to) == 0) {
+                    return &mailboxes[i];
+                }
+            }
+            return NULL;
+        }
+    }
+    $cc proc share {char* from char* to char* statements} void {
+        mailbox_t* mailbox = find(from, to);
+        if (!mailbox) {
+            fprintf(stderr, "Could not find mailbox for '%s -> %s'.\n", from, to);
+            exit(1);
+        }
+        pthread_mutex_lock(&mailbox->mutex); {
+            mailbox->mailLen = snprintf(mailbox->mail, sizeof(mailbox->mail), "%s", statements);
+        } pthread_mutex_unlock(&mailbox->mutex);
+    }
+    $cc proc receive {char* from char* to} Tcl_Obj* {
+        mailbox_t* mailbox = find(from, to);
+        if (!mailbox) { return Tcl_NewStringObj("", -1); }
+        Tcl_Obj* ret;
+        pthread_mutex_lock(&mailbox->mutex); {
+            ret = Tcl_NewStringObj(mailbox->mail, mailbox->mailLen);
+        } pthread_mutex_unlock(&mailbox->mutex);
+        return ret;
+    }
+    $cc compile
+    init
+}
+
 if {[info exists ::entry]} {
     source "lib/process.tcl"
     Zygote::init
diff --git a/pi/AprilTags.tcl b/pi/AprilTags.tcl
index a489a1f4..69079813 100644
--- a/pi/AprilTags.tcl
+++ b/pi/AprilTags.tcl
@@ -17,12 +17,12 @@ namespace eval AprilTags {
         td = apriltag_detector_create();
         tf = tagStandard52h13_create();
         apriltag_detector_add_family_bits(td, tf, 1);
-        td->nthreads = 2;
+        td->nthreads = 1;
     }
 
     apc proc detect {image_t gray} Tcl_Obj* {
         assert(gray.components == 1);
-        image_u8_t im = (image_u8_t) { .width = gray.width, .height = gray.height, .stride = gray.width, .buf = gray.data };
+        image_u8_t im = (image_u8_t) { .width = gray.width, .height = gray.height, .stride = gray.bytesPerRow, .buf = gray.data };
     
         zarray_t *detections = apriltag_detector_detect(td, &im);
         int detectionCount = zarray_size(detections);
diff --git a/pi/Display.tcl b/pi/Display.tcl
index 1ecc8e69..3983d664 100644
--- a/pi/Display.tcl
+++ b/pi/Display.tcl
@@ -1,5 +1,3 @@
-source "lib/language.tcl"
-source "lib/c.tcl"
 source "pi/cUtils.tcl"
 
 namespace eval Display {}
@@ -56,12 +54,12 @@ dc code {
     static void commitThenClearStaging();
 
     pixel_t* staging;
+    pixel_t* fbmem;
 
     struct {
         pixel_t* mem;
         uint32_t id;
     } fbs[2];
-    int currentFbIndex;
 
     int fbwidth;
     int fbheight;
@@ -130,10 +128,11 @@ dc proc setupGpu {} void {
             fprintf(stderr, "Display: cannot open '%s': %m\n", card);
             exit(1);
         }
-        if (drmSetMaster(gpuFd) != 0) {
+        while (drmSetMaster(gpuFd) != 0) {
             fprintf(stderr, "Display: cannot become DRM master on '%s': %m\n", card);
-            exit(1);
+            fprintf(stderr, "Display: waiting 1 s...\n"); sleep(1);
         }
+        fprintf(stderr, "Display: successfully became DRM master on '%s'\n", card);
         uint64_t hasDumb;
         if (drmGetCap(gpuFd, DRM_CAP_DUMB_BUFFER, &hasDumb) < 0 || !hasDumb) {
             fprintf(stderr, "Display: drm device '%s' does not support dumb buffers\n", card);
@@ -198,12 +197,18 @@ dc proc setupGpu {} void {
     }
 
     setupFb(0);
-    setupFb(1);
+    fbmem = fbs[0].mem;
+    staging = ckalloc(fbwidth * fbheight * sizeof(pixel_t));
 
-    // Can't drop master if we're going to flip buffers at runtime.
+    int ret = drmModeSetCrtc(gpuFd, gpuEnc->crtc_id, fbs[0].id, 0, 0,
+                             &gpuConn->connector_id, 1, &gpuConn->modes[0]);
+    if (ret) {
+        fprintf(stderr, "Display: cannot flip CRTC to %d for connector %u (%d): %m\n",
+                0, gpuConn->connector_id, errno);
+        exit(1);
+    }
+    
     // drmDropMaster(gpuFd);
-
-    commitThenClearStaging();
 }
 dc proc setupFb {int idx} void [csubst {
     struct drm_mode_create_dumb dumb;
@@ -239,19 +244,11 @@ dc proc setupFb {int idx} void [csubst {
 }]
 # Hack to support old stuff that uses framebuffer directly and doesn't commit.
 dc proc getFbPointer {} pixel_t* {
-    return fbs[currentFbIndex].mem;
+    return fbmem;
 }
 dc proc commitThenClearStaging {} void {
-    currentFbIndex = !currentFbIndex;
-    int ret = drmModeSetCrtc(gpuFd, gpuEnc->crtc_id, fbs[currentFbIndex].id, 0, 0,
-                             &gpuConn->connector_id, 1, &gpuConn->modes[0]);
-    if (ret) {
-        fprintf(stderr, "Display: cannot flip CRTC to %d for connector %u (%d): %m\n",
-                currentFbIndex,
-                gpuConn->connector_id, errno);
-        exit(1);
-    }
-    staging = fbs[!currentFbIndex].mem;
+    memcpy(fbmem, staging, fbwidth * fbheight * sizeof(pixel_t));
+    // This memset takes ~2ms on 1080p on a Pi 4.
     memset(staging, 0, fbwidth * fbheight * sizeof(pixel_t));
 }
 
@@ -349,15 +346,23 @@ dc proc drawCircle {int x0 int y0 int radius int color} void {
 
 defineImageType dc
 dc proc drawImageTransparent {int x0 int y0 image_t image int transparentTone int scale} void {
-    if (image.components != 1) { exit(1); }
     for (int y = 0; y < image.height; y++) {
         for (int x = 0; x < image.width; x++) {
 
-	    // Index into image to get color
-            int i = y*image.bytesPerRow + x*image.components;
+	    // index into image to get color
+            int i = y*image.bytesPerRow + x*image.components; (void)i;
             uint8_t r; uint8_t g; uint8_t b;
-            if (image.data[i] == transparentTone) { continue; }
-            r = image.data[i]; g = image.data[i]; b = image.data[i];
+            if (image.components == 1) {
+                if (image.data[i] == transparentTone) { continue; }
+                r = image.data[i]; g = image.data[i]; b = image.data[i];
+            } else if (image.components == 3) {
+                if (image.data[i] == transparentTone &&
+                    image.data[i + 1] == transparentTone &&
+                    image.data[i + 2] == transparentTone) {
+                    continue;
+                }
+                r = image.data[i]; g = image.data[i + 1]; b = image.data[i + 2];
+            }
 
 	    // Write repeatedly to framebuffer to scale up image
 	    for (int dy = 0; dy < scale; dy++) {
@@ -368,44 +373,58 @@ dc proc drawImageTransparent {int x0 int y0 image_t image int transparentTone in
 		    if (sx < 0 || fbwidth <= sx || sy < 0 || fbheight <= sy) continue;
 
 		    staging[sy*fbwidth + sx] = PIXEL(r, g, b);
-
 		}
 	    }
         }
     }
 }
-dc proc drawImage {int x0 int y0 image_t image int scale} void {
-    for (int y = 0; y < image.height; y++) {
-        for (int x = 0; x < image.width; x++) {
-
-	    // Index into image to get color
-            int i = y*image.bytesPerRow + x*image.components;
-            uint8_t r; uint8_t g; uint8_t b;
-            if (image.components == 3) {
-                r = image.data[i]; g = image.data[i+1]; b = image.data[i+2];
-            } else if (image.components == 1) {
-                r = image.data[i]; g = image.data[i]; b = image.data[i];
-            } else {
-                exit(1);
-            }
+source "pi/rotate.tcl"
+dc proc drawImage {int x0 int y0 image_t image double radians int scale} void {
+    double radiansNormalized = fmod(radians, 2.0 * M_PI);
+    if (radiansNormalized > M_PI) {
+        radiansNormalized -= 2.0 * M_PI;
+    } else if (radiansNormalized < -M_PI) {
+        radiansNormalized += 2.0 * M_PI;
+    }
+    int imageX; int imageY;
+    image_t temp = rotateMakeImage(image.width, image.height, image.components,
+                                   radiansNormalized,
+                                   &imageX, &imageY);
 
-	    // Write repeatedly to framebuffer to scale up image
-	    for (int dy = 0; dy < scale; dy++) {
-		for (int dx = 0; dx < scale; dx++) {
+    // Draw the image into the temp image.
+    for (int y = 0; y < image.height; y++) {
+        memcpy(&temp.data[(y + imageY) * temp.bytesPerRow + imageX * temp.components],
+               &image.data[y * image.bytesPerRow],
+               image.width * image.components);
+    }
+    
+    rotate(temp, imageX, imageY, image.width, image.height, radiansNormalized);
 
-		    int sx = x0 + scale * x + dx;
-		    int sy = y0 + scale * y + dy;
-		    if (sx < 0 || fbwidth <= sx || sy < 0 || fbheight <= sy) continue;
+    // Find corners of rotated rectangle
+    Vec2i topLeft = Vec2i_rotate((Vec2i) {-(int)image.width/2, -(int)image.height/2}, radiansNormalized);
+    Vec2i topRight = Vec2i_rotate((Vec2i) {image.width/2, -(int)image.height/2}, radiansNormalized);
+    Vec2i bottomLeft = Vec2i_rotate((Vec2i) {-(int)image.width/2, image.height/2}, radiansNormalized);
+    Vec2i bottomRight = Vec2i_rotate((Vec2i) {image.width/2, image.height/2}, radiansNormalized);
 
-		    staging[sy*fbwidth + sx] = PIXEL(r, g, b);
+    // Now blit the offscreen buffer to the screen.
+    image_t rotatedImage = {
+        .width = max4(topLeft.x, topRight.x, bottomLeft.x, bottomRight.x) -
+                   min4(topLeft.x, topRight.x, bottomLeft.x, bottomRight.x),
+        .height = max4(topLeft.y, topRight.y, bottomLeft.y, bottomRight.y) -
+                    min4(topLeft.y, topRight.y, bottomLeft.y, bottomRight.y),
+        .components = temp.components,
+        .bytesPerRow = temp.bytesPerRow
+    };
+    int rotatedImageX0 = (temp.width - rotatedImage.width) / 2;
+    int rotatedImageY0 = (temp.height - rotatedImage.height) / 2;
+    rotatedImage.data = &temp.data[rotatedImageY0*temp.bytesPerRow + rotatedImageX0*temp.components];
 
-		}
-	    }
-        }
-    }
+    drawImageTransparent(x0 - rotatedImage.width*scale/2,
+                         y0 - rotatedImage.height*scale/2,
+                         rotatedImage, 0x00, scale);
+    ckfree(temp.data);
 }
 
-source "pi/rotate.tcl"
 dc proc drawText {int x0 int y0 double radians int scale char* text} void {
     // Draws text (breaking at linebreaks), with the center of the
     // text at (x0, y0). Rotates counterclockwise up from the
@@ -628,8 +647,8 @@ namespace eval Display {
         }
     }
 
-    proc image {x y im {scale 1.0}} {
-        drawImage [expr {int($x)}] [expr {int($y)}] $im [expr {int($scale)}]
+    proc image {x y im {radians 0} {scale 1.0}} {
+        drawImage [expr {int($x)}] [expr {int($y)}] $im $radians [expr {int($scale)}]
     }
 
     # for debugging
diff --git a/pi/KeyCodes.tcl b/pi/KeyCodes.tcl
index 4ca8d4ad..87a59500 100644
--- a/pi/KeyCodes.tcl
+++ b/pi/KeyCodes.tcl
@@ -1,129 +1,143 @@
 set KeyCodes [dict create]
-proc define {name code} {
-    upvar KeyCodes KeyCodes
-    dict set KeyCodes $code $name
+
+proc keydef {code val {shiftVal ""}} {
+  upvar KeyCodes KeyCodes
+  if {$shiftVal == ""} {
+    set shiftVal $val
+  }
+  dict set KeyCodes $code [list $val $shiftVal]
+}
+
+proc keyFromCode {code {shift false}} {
+  upvar KeyCodes KeyCodes
+  if {[dict exists $KeyCodes $code]} {
+    set vals [dict get $KeyCodes $code]
+    return [lindex $vals [expr {$shift ? 1 : 0}]]
+  }
+  puts "WARNING: unknown key code \"$code\""
+  return "?"
 }
 
-# from https://github.com/torvalds/linux/blob/master/include/uapi/linux/input-event-codes.h
-define KEY_RESERVED		0
-define KEY_ESC			1
-define KEY_1			2
-define KEY_2			3
-define KEY_3			4
-define KEY_4			5
-define KEY_5			6
-define KEY_6			7
-define KEY_7			8
-define KEY_8			9
-define KEY_9			10
-define KEY_0			11
-define KEY_MINUS		12
-define KEY_EQUAL		13
-define KEY_BACKSPACE		14
-define KEY_TAB			15
-define KEY_Q			16
-define KEY_W			17
-define KEY_E			18
-define KEY_R			19
-define KEY_T			20
-define KEY_Y			21
-define KEY_U			22
-define KEY_I			23
-define KEY_O			24
-define KEY_P			25
-define KEY_LEFTBRACE		26
-define KEY_RIGHTBRACE		27
-define KEY_ENTER		28
-define KEY_LEFTCTRL		29
-define KEY_A			30
-define KEY_S			31
-define KEY_D			32
-define KEY_F			33
-define KEY_G			34
-define KEY_H			35
-define KEY_J			36
-define KEY_K			37
-define KEY_L			38
-define KEY_SEMICOLON		39
-define KEY_APOSTROPHE		40
-define KEY_GRAVE		41
-define KEY_LEFTSHIFT		42
-define KEY_BACKSLASH		43
-define KEY_Z			44
-define KEY_X			45
-define KEY_C			46
-define KEY_V			47
-define KEY_B			48
-define KEY_N			49
-define KEY_M			50
-define KEY_COMMA		51
-define KEY_DOT			52
-define KEY_SLASH		53
-define KEY_RIGHTSHIFT		54
-define KEY_KPASTERISK		55
-define KEY_LEFTALT		56
-define KEY_SPACE		57
-define KEY_CAPSLOCK		58
-define KEY_F1			59
-define KEY_F2			60
-define KEY_F3			61
-define KEY_F4			62
-define KEY_F5			63
-define KEY_F6			64
-define KEY_F7			65
-define KEY_F8			66
-define KEY_F9			67
-define KEY_F10			68
-define KEY_NUMLOCK		69
-define KEY_SCROLLLOCK		70
-define KEY_KP7			71
-define KEY_KP8			72
-define KEY_KP9			73
-define KEY_KPMINUS		74
-define KEY_KP4			75
-define KEY_KP5			76
-define KEY_KP6			77
-define KEY_KPPLUS		78
-define KEY_KP1			79
-define KEY_KP2			80
-define KEY_KP3			81
-define KEY_KP0			82
-define KEY_KPDOT		83
+# Keycodes from https://github.com/torvalds/linux/blob/master/include/uapi/linux/input-event-codes.h
+keydef 0		{RESERVED}
+keydef 1		{ESC}
+keydef 2		{1} {!}
+keydef 3		{2} {@}
+keydef 4		{3} {#}
+keydef 5		{4} {$}
+keydef 6		{5} {%}
+keydef 7		{6} {^}
+keydef 8		{7} {&}
+keydef 9		{8} {*}
+keydef 10		{9} {(}
+keydef 11		{0} {)}
+keydef 12		{-} {_}
+keydef 13		{=} {+}
+keydef 14		{BACKSPACE}
+keydef 15		{TAB}
+keydef 16		{q} {Q}
+keydef 17		{w} {W}
+keydef 18		{e} {E}
+keydef 19		{r} {R}
+keydef 20		{t} {T}
+keydef 21		{y} {Y}
+keydef 22		{u} {U}
+keydef 23		{i} {I}
+keydef 24		{o} {O}
+keydef 25		{p} {P}
+keydef 26		{[} "\{"
+keydef 27		{]} "\}"
+keydef 28		{ENTER}
+keydef 29		{LEFTCTRL}
+keydef 30		{a} {A}
+keydef 31		{s} {S}
+keydef 32		{d} {D}
+keydef 33		{f} {F}
+keydef 34		{g} {G}
+keydef 35		{h} {H}
+keydef 36		{j} {J}
+keydef 37		{k} {K}
+keydef 38		{l} {L}
+keydef 39		{;} {:}
+keydef 40		{'} "\""
+keydef 41		{`} {~}
+keydef 42		{LEFTSHIFT}
+keydef 43		"\\" {|}
+keydef 44		{z} {Z}
+keydef 45		{x} {X}
+keydef 46		{c} {C}
+keydef 47		{v} {V}
+keydef 48		{b} {B}
+keydef 49		{n} {N}
+keydef 50		{m} {M}
+keydef 51		{,} {<}
+keydef 52		{.} {>}
+keydef 53		{/} {?}
+keydef 54		{RIGHTSHIFT}
+keydef 55		{KPASTERISK}
+keydef 56		{LEFTALT}
+keydef 57		{ } ;# SPACE
+keydef 58		{CAPSLOCK}
+keydef 59		{F1}
+keydef 60		{F2}
+keydef 61		{F3}
+keydef 62		{F4}
+keydef 63		{F5}
+keydef 64		{F6}
+keydef 65		{F7}
+keydef 66		{F8}
+keydef 67		{F9}
+keydef 68		{F10}
+keydef 69		{NUMLOCK}
+keydef 70		{SCROLLLOCK}
+keydef 71		{KP7}
+keydef 72		{KP8}
+keydef 73		{KP9}
+keydef 74		{KPMINUS}
+keydef 75		{KP4}
+keydef 76		{KP5}
+keydef 77		{KP6}
+keydef 78		{KPPLUS}
+keydef 79		{KP1}
+keydef 80		{KP2}
+keydef 81		{KP3}
+keydef 82		{KP0}
+keydef 83		{KPDOT}
 
-define KEY_ZENKAKUHANKAKU	85
-define KEY_102ND		86
-define KEY_F11			87
-define KEY_F12			88
-define KEY_RO			89
-define KEY_KATAKANA		90
-define KEY_HIRAGANA		91
-define KEY_HENKAN		92
-define KEY_KATAKANAHIRAGANA	93
-define KEY_MUHENKAN		94
-define KEY_KPJPCOMMA		95
-define KEY_KPENTER		96
-define KEY_RIGHTCTRL		97
-define KEY_KPSLASH		98
-define KEY_SYSRQ		99
-define KEY_RIGHTALT		100
-define KEY_LINEFEED		101
-define KEY_HOME		102
-define KEY_UP			103
-define KEY_PAGEUP		104
-define KEY_LEFT		105
-define KEY_RIGHT		106
-define KEY_END			107
-define KEY_DOWN		108
-define KEY_PAGEDOWN		109
-define KEY_INSERT		110
-define KEY_DELETE		111
-define KEY_MACRO		112
-define KEY_MUTE		113
-define KEY_VOLUMEDOWN		114
-define KEY_VOLUMEUP		115
-define KEY_POWER		116
-define KEY_KPEQUAL		117
-define KEY_KPPLUSMINUS		118
-define KEY_PAUSE		119
-define KEY_SCALE		120
+keydef 85		{ZENKAKUHANKAKU}
+keydef 86		{102ND}
+keydef 87		{F11}
+keydef 88		{F12}
+keydef 89		{RO}
+keydef 90		{KATAKANA}
+keydef 91		{HIRAGANA}
+keydef 92		{HENKAN}
+keydef 93		{KATAKANAHIRAGANA}
+keydef 94		{MUHENKAN}
+keydef 95		{KPJPCOMMA}
+keydef 96		{KPENTER}
+keydef 97		{RIGHTCTRL}
+keydef 98		{KPSLASH}
+keydef 99		{SYSRQ}
+keydef 100		{RIGHTALT}
+keydef 101		{LINEFEED}
+keydef 102		{HOME}
+keydef 103		{UP}
+keydef 104		{PAGEUP}
+keydef 105		{LEFT}
+keydef 106		{RIGHT}
+keydef 107		{END}
+keydef 108		{DOWN}
+keydef 109		{PAGEDOWN}
+keydef 110		{INSERT}
+keydef 111		{DELETE}
+keydef 112		{MACRO}
+keydef 113		{MUTE}
+keydef 114		{VOLUMEDOWN}
+keydef 115		{VOLUMEUP}
+keydef 116		{POWER}
+keydef 117		{KPEQUAL}
+keydef 118		{KPPLUSMINUS}
+keydef 119		{PAUSE}
+keydef 120		{SCALE}
 
diff --git a/pi/Keyboard.tcl b/pi/Keyboard.tcl
index d578e0b5..b393aaf1 100644
--- a/pi/Keyboard.tcl
+++ b/pi/Keyboard.tcl
@@ -1,6 +1,4 @@
 namespace eval Keyboard {
-    source "pi/KeyCodes.tcl"
-
     variable kb
 
     proc init {} {
@@ -33,7 +31,18 @@ namespace eval Keyboard {
         fconfigure $kb -translation binary
     }
 
-    proc getChar {} {
+    # Event size depends on sizeof(long). Default to 32-bit longs
+    variable evtBytes 16
+    variable evtFormat iissi
+    if {[exec getconf LONG_BIT] == 64} {
+      set evtBytes 24
+      set evtFormat wwssi
+    }
+
+    proc getKeyEvent {} {
+        variable evtBytes
+        variable evtFormat
+
         # See https://www.kernel.org/doc/Documentation/input/input.txt
         # https://www.kernel.org/doc/Documentation/input/event-codes.txt
         # https://github.com/torvalds/linux/blob/master/include/uapi/linux/input-event-codes.h
@@ -42,27 +51,14 @@ namespace eval Keyboard {
         #     struct timeval time;
         #     unsigned short type; (should be EV_KEY = 0x01)
         #     unsigned short code; (scancode; for example, 16 = q)
-        #     unsigned int value; (should be 1 for keypress)
+        #     unsigned int value; (0 for key release, 1 for press, 2 for repeat)
         # };
         #
         while 1 {
-            binary scan [read $Keyboard::kb 16] nntutunu tvSec tvUsec type code value
-            if {$type == 0x01 && $value == 1} break
+            binary scan [read $Keyboard::kb $evtBytes] $evtFormat tvSec tvUsec type code value
+            if {$type == 0x01} {
+                return [list $code $value]
+            }
         }
-        # TODO: Should properly catch this error
-        # e.g. Jan 28 04:11:28 folk0 make[1991]: Thread error: tid0x7f45fd2b0640 can't\ read\ \"name\":\ no\ such\ variable ...
-
-        # scancode name, like KEY_A
-        catch { set name [dict get $Keyboard::KeyCodes $code] } err
-        set ch [string tolower [string range $name 4 end]]
-        # puts "type $type code $code value $value ($ch)"
-        return $ch
     }
 }
-
-if {[info exists ::argv0] && $::argv0 eq [info script]} {
-    Keyboard::init
-    puts [Keyboard::getChar]
-    puts [Keyboard::getChar]
-    puts [Keyboard::getChar]
-}
diff --git a/pi/pi.tcl b/pi/pi.tcl
index 2a50f549..e3b78b6a 100644
--- a/pi/pi.tcl
+++ b/pi/pi.tcl
@@ -2,92 +2,46 @@ package require Thread
 proc errorproc {id errorInfo} {puts "Thread error in $id: $errorInfo"}
 thread::errorproc errorproc
 
-namespace eval Display {
-    variable WIDTH
-    variable HEIGHT
-    regexp {mode "(\d+)x(\d+)"} [exec fbset] -> WIDTH HEIGHT
-
-    variable displayThread [thread::create {
-        source pi/Display.tcl
-        Display::init
-        puts "Display tid: [getTid]"
-
-        set ::displayCount 0
-        thread::wait
-    }]
-    puts "Display thread id: $displayThread"
-
-    proc stroke {points width color} {
-        uplevel [list Wish display runs [list Display::stroke $points $width $color]]
-    }
-
-    proc circle {x y radius thickness color} {
-        uplevel [list Wish display runs [list Display::circle $x $y $radius $thickness $color]]
-    }
-
-    proc text args {
-        uplevel [list Wish display runs [list Display::text {*}$args]]
-    }
-
-    proc fillTriangle args {
-        uplevel [list Wish display runs [list Display::fillTriangle {*}$args]]
-    }
-
-    proc fillQuad args {
-        uplevel [list Wish display runs [list Display::fillQuad {*}$args]]
-    }
-
-    proc fillPolygon args {
-        uplevel [list Wish display runs [list Display::fillPolygon {*}$args]]
-    }
-
-    variable displayTime none
-    proc commit {} {
-        set displayList [list]
-        foreach match [Statements::findMatches {/someone/ wishes display runs /command/}] {
-            lappend displayList [dict get $match command]
-        }
-
-        proc lcomp {a b} {expr {[lindex $a 0] == "Display::text"}}
-        incr ::displayCount
-        thread::send -head -async $Display::displayThread [format {
-            set newDisplayCount %d
-            if {$::displayCount > $newDisplayCount} {
-                # we've already displayed a newer frame
-                return
-            } else {
-                set ::displayCount $newDisplayCount
-            }
- 
-            # Draw the display list
-            set displayTime [time {
-                %s
-                commitThenClearStaging
-            }]
-            thread::send -async "%s" [subst {
-                set Display::displayTime "$displayTime"
-            }]
-        } $::displayCount \
-          [join [lsort -command lcomp $displayList] "\n"] \
-          [thread::id]]
-    }
-}
-
 try {
     set keyboardThread [thread::create [format {
         source "pi/Keyboard.tcl"
+        source "pi/KeyCodes.tcl"
         source "lib/c.tcl"
         source "pi/cUtils.tcl"
         Keyboard::init
         puts "Keyboard tid: [getTid]"
 
-        set chs [list]
+        set keyStates [list up down repeat]
+        set modifiers [dict create \
+            shift 0 \
+            ctrl 0 \
+            alt 0 \
+        ]
+
         while true {
-            lappend chs [Keyboard::getChar]
+            lassign [Keyboard::getKeyEvent] keyCode eventType
+
+            set shift [dict get $modifiers shift]
+            set key [keyFromCode $keyCode $shift]
+            set keyState [lindex $keyStates $eventType]
+
+            set isDown [expr {$keyState != "up"}]
+            if {[string match *SHIFT $key]} {
+              dict set modifiers shift $isDown
+            }
+            if {[string match *CTRL $key]} {
+              dict set modifiers ctrl $isDown
+            }
+            if {[string match *ALT $key]} {
+              dict set modifiers alt $isDown
+            }
+
+            set heldModifiers [dict keys [dict filter $modifiers value 1]]
 
+            # Use `list` to escape special chars (brackets, quotes, whitespace)
             thread::send -async "%s" [subst {
-                Retract keyboard claims the keyboard character log is /something/
-                Assert keyboard claims the keyboard character log is "$chs"
+                Retract keyboard claims key /k/ is /t/ with modifiers /m/
+                Assert keyboard claims key [list $key] is [list $keyState] with modifiers [list $heldModifiers]
             }]
         }
     } [thread::id]]]
diff --git a/pi/rotate.tcl b/pi/rotate.tcl
index 028ffc35..8a196471 100644
--- a/pi/rotate.tcl
+++ b/pi/rotate.tcl
@@ -30,9 +30,9 @@ dc proc shearY {image_t sprite int x0 int y0 int width int height double sy} voi
                 int shear = sy * (x - x0);
                 int from = y*sprite.bytesPerRow + x*sprite.components;
                 int to = (y + shear)*sprite.bytesPerRow + x*sprite.components;
-                sprite.data[to] = sprite.data[from];
+                memmove(&sprite.data[to], &sprite.data[from], sprite.components);
                 // Blot out the unsheared part
-                if (from != to) { sprite.data[from] = 0x00; }
+                if (from != to) { memset(&sprite.data[from], 0x00, sprite.components); }
             }
         }
     } else if (sy < 0) {
@@ -41,9 +41,9 @@ dc proc shearY {image_t sprite int x0 int y0 int width int height double sy} voi
                 int shear = sy * (x - x0); // Is negative.
                 int from = y*sprite.bytesPerRow + x*sprite.components;
                 int to = (y + shear)*sprite.bytesPerRow + x*sprite.components;
-                sprite.data[to] = sprite.data[from];
+                memmove(&sprite.data[to], &sprite.data[from], sprite.components);
                 // Blot out the unsheared part
-                if (from != to) { sprite.data[from] = 0x00; }
+                if (from != to) { memset(&sprite.data[from], 0x00, sprite.components); }
             }
         }
     }
@@ -56,9 +56,9 @@ dc proc rotate180 {image_t sprite int x0 int y0 int width int height} void {
     int icenter = imin + (imax - imin)/2;
     for (int i = imin; i < icenter; i += sprite.components) {
         int j = imax - (i - imin);
-        uint8_t temp = sprite.data[i];
-        sprite.data[i] = sprite.data[j];
-        sprite.data[j] = temp;
+        uint8_t temp[sprite.components]; memcpy(temp, &sprite.data[i], sprite.components);
+        memmove(&sprite.data[i], &sprite.data[j], sprite.components);
+        memcpy(&sprite.data[j], temp, sprite.components);
     }
 }
 dc proc rotateMakeImage {int width int height int components double radians
diff --git a/test/stale.tcl b/test/stale.tcl
new file mode 100644
index 00000000..7b2fcd70
--- /dev/null
+++ b/test/stale.tcl
@@ -0,0 +1,6 @@
+for {set i 0} {$i < 30000} {incr i} {
+    Commit [list Claim the iteration count is $i]
+    Step
+}
+
+assert {[llength [Statements::findMatches [list /someone/ claims the iteration count is /i/]]] == 1}
diff --git a/test/survival.tcl b/test/survival.tcl
new file mode 100644
index 00000000..914ab45d
--- /dev/null
+++ b/test/survival.tcl
@@ -0,0 +1,25 @@
+Assert when we are running {{} {
+    When the collected matches for [list tag /k/ was seen by /x/ at /p/] are /matches/ {
+        set tagsSeen [dict create]
+        foreach m $matches {
+            dict set tagsSeen [dict get $m k] true
+        }
+        dict for {k _} $tagsSeen { Claim tag $k is a tag }
+    }
+    When tag /k/ is a tag {
+        puts "Saw tag $k"
+        On unmatch { error "Should never unmatch" }
+    }
+}}
+Assert we are running
+Step
+
+Commit Omar { Claim tag 1 was seen by Omar at home }
+Commit Mom { Claim tag 1 was seen by Mom at restaurant }
+Step
+
+Commit Omar { Claim tag 1 was seen by Omar at work }
+Step
+
+# Statements::print
+
diff --git a/user-programs/haippi7/web-image.folk b/user-programs/haippi7/web-image.folk
index 8c437ce9..d06df1b3 100644
--- a/user-programs/haippi7/web-image.folk
+++ b/user-programs/haippi7/web-image.folk
@@ -1,91 +1,9 @@
-set cc [c create]
-$cc cflags -L[lindex [exec /usr/sbin/ldconfig -p | grep libjpeg] end]
-
-# defineImageType $cc
-# for some reason defineImageType doesn't work here so we do it manually
-$cc code {
-    typedef struct {
-        uint32_t width;
-        uint32_t height;
-        int components;
-        uint32_t bytesPerRow;
-
-        uint8_t *data;
-    } image_t;
-}
-
-$cc argtype image_t {
-    image_t $argname; sscanf(Tcl_GetString($obj), "width %u height %u components %d bytesPerRow %u data 0x%p", &$argname.width, &$argname.height, &$argname.components, &$argname.bytesPerRow, &$argname.data);
-}
-$cc rtype image_t {
-    $robj = Tcl_ObjPrintf("width %u height %u components %d bytesPerRow %u data 0x%" PRIxPTR, $rvalue.width, $rvalue.height, $rvalue.components, $rvalue.bytesPerRow, (uintptr_t) $rvalue.data);
-}
-
-$cc include <stdlib.h>
-$cc include <string.h>
-$cc include <jpeglib.h>
-
-$cc code {
-    #include <jpeglib.h>
-    #include <stdint.h>
-    #include <unistd.h>
-
-    void 
-jpeg(FILE* dest, uint8_t* rgb, uint32_t width, uint32_t height, int quality)
-{
-  JSAMPARRAY image;
-  image = calloc(height, sizeof (JSAMPROW));
-  for (size_t i = 0; i < height; i++) {
-    image[i] = calloc(width * 3, sizeof (JSAMPLE));
-    for (size_t j = 0; j < width; j++) {
-      image[i][j * 3 + 0] = rgb[(i * width + j)];
-      image[i][j * 3 + 1] = rgb[(i * width + j)];
-      image[i][j * 3 + 2] = rgb[(i * width + j)];
-    }
-  }
-  
-  struct jpeg_compress_struct compress;
-  struct jpeg_error_mgr error;
-  compress.err = jpeg_std_error(&error);
-  jpeg_create_compress(&compress);
-  jpeg_stdio_dest(&compress, dest);
-  
-  compress.image_width = width;
-  compress.image_height = height;
-  compress.input_components = 3;
-  compress.in_color_space = JCS_RGB;
-  jpeg_set_defaults(&compress);
-  jpeg_set_quality(&compress, quality, TRUE);
-  jpeg_start_compress(&compress, TRUE);
-  jpeg_write_scanlines(&compress, image, height);
-  jpeg_finish_compress(&compress);
-  jpeg_destroy_compress(&compress);
-
-  for (size_t i = 0; i < height; i++) {
-    free(image[i]);
-  }
-  free(image);
-}
-
-}
-
-
-$cc proc saveTempImage {image_t im char* filename} void {
-	// write capture to jpeg
-    // char filename[100] = "web-image-test.jpg";
-    FILE* out = fopen(filename, "w");
-    jpeg(out, im.data, im.width, im.height, 100);
-    fclose(out);
-}
-c loadlib [lindex [exec /usr/sbin/ldconfig -p | grep libjpeg] end]
-$cc compile
-
 When the camera frame is /im/ {
   Wish the web server handles route "/frame-image/$" with handler [list apply {{im} {
     # set width [dict get $im width]
     # set height [dict get $im height]
     set filename "/tmp/web-image-frame.jpg"
-    saveTempImage $im $filename
+    image saveAsJpeg $im $filename
     set fsize [file size $filename]
     set fd [open $filename r]
     fconfigure $fd -encoding binary -translation binary
@@ -93,4 +11,4 @@ When the camera frame is /im/ {
     close $fd
     dict create statusAndHeaders "HTTP/1.1 200 OK\nConnection: close\nContent-Type: image/jpeg\nContent-Length: $fsize\n\n" body $body
   }} $im]
-}
\ No newline at end of file
+}
diff --git a/vendor/libtmt/README.rst b/vendor/libtmt/README.rst
new file mode 100644
index 00000000..f3819df9
--- /dev/null
+++ b/vendor/libtmt/README.rst
@@ -0,0 +1,637 @@
+
+============================================
+libtmt - a simple terminal emulation library
+============================================
+
+libtmt is the Tiny Mock Terminal Library.  It provides emulation of a classic
+smart text terminal, by maintaining an in-memory screen image.  Sending text
+and command sequences to libtmt causes it to update this in-memory image,
+which can then be examined and rendered however the user sees fit.
+
+The imagined primary goal for libtmt is to for terminal emulators and
+multiplexers; it provides the terminal emulation layer for the `mtm`_
+terminal multiplexer, for example. Other uses include screen-scraping and
+automated test harnesses.
+
+libtmt is similar in purpose to `libtsm`_, but considerably smaller (500
+lines versus 6500 lines). libtmt is also, in this author's humble opinion,
+considerably easier to use.
+
+.. _`mtm`: https://github.com/deadpixi/mtm
+.. _`libtsm`: https://www.freedesktop.org/wiki/Software/kmscon/libtsm/
+
+Major Features and Advantages
+=============================
+
+Works Out-of-the-Box
+    libtmt emulates a well-known terminal type (`ansi`), the definition of
+    which has been in the terminfo database since at least 1995.  There's no
+    need to install a custom terminfo entry.  There's no claiming to be an
+    xterm but only emulating a small subset of its features. Any program
+    using terminfo works automatically: this includes vim, emacs, mc,
+    cmus, nano, nethack, ...
+
+Portable
+    Written in pure C99.
+    Optionally, the POSIX-mandated `wcwidth` function can be used, which
+    provides minimal support for combining characters.
+
+Small
+    Less than 500 lines of C, including comments and whitespace.
+
+Free
+    Released under a BSD-style license, free for commercial and
+    non-commerical use, with no restrictions on source code release or
+    redistribution.
+
+Simple
+    Only 8 functions to learn, and really you can get by with 6!
+
+International
+    libtmt internally uses wide characters exclusively, and uses your C
+    library's multibyte encoding functions.
+    This means that the library automatically supports any encoding that
+    your operating system does.
+
+How to Use libtmt
+=================
+
+libtmt is a single C file and a single header.  Just include these files
+in your project and you should be good to go.
+
+By default, libtmt uses only ISO standard C99 features,
+but see `Compile-Time Options`_ below.
+
+Example Code
+------------
+
+Below is a simple program fragment giving the flavor of libtmt.
+Note that another good example is the `mtm`_ terminal multiplexer:
+
+.. _`mtm`: https://github.com/deadpixi/mtm
+
+.. code:: c
+
+    #include <stdio.h>
+    #include <stdlib.h>
+    #include "tmt.h"
+
+    /* Forward declaration of a callback.
+     * libtmt will call this function when the terminal's state changes.
+     */
+    void callback(tmt_msg_t m, TMT *vt, const void *a, void *p);
+
+    int
+    main(void)
+    {
+        /* Open a virtual terminal with 2 lines and 10 columns.
+         * The first NULL is just a pointer that will be provided to the
+         * callback; it can be anything. The second NULL specifies that
+         * we want to use the default Alternate Character Set; this
+         * could be a pointer to a wide string that has the desired
+         * characters to be displayed when in ACS mode.
+         */
+        TMT *vt = tmt_open(2, 10, callback, NULL, NULL);
+        if (!vt)
+            return perror("could not allocate terminal"), EXIT_FAILURE;
+
+        /* Write some text to the terminal, using escape sequences to
+         * use a bold rendition.
+         *
+         * The final argument is the length of the input; 0 means that
+         * libtmt will determine the length dynamically using strlen.
+         */
+        tmt_write(vt, "\033[1mhello, world (in bold!)\033[0m", 0);
+
+        /* Writing input to the virtual terminal can (and in this case, did)
+         * call the callback letting us know the screen was updated. See the
+         * callback below to see how that works.
+         */
+        tmt_close(vt);
+        return EXIT_SUCCESS;
+    }
+
+    void
+    callback(tmt_msg_t m, TMT *vt, const void *a, void *p)
+    {
+        /* grab a pointer to the virtual screen */
+        const TMTSCREEN *s = tmt_screen(vt);
+        const TMTPOINT *c = tmt_cursor(vt);
+
+        switch (m){
+            case TMT_MSG_BELL:
+                /* the terminal is requesting that we ring the bell/flash the
+                 * screen/do whatever ^G is supposed to do; a is NULL
+                 */
+                printf("bing!\n");
+                break;
+
+            case TMT_MSG_UPDATE:
+                /* the screen image changed; a is a pointer to the TMTSCREEN */
+                for (size_t r = 0; r < s->nline; r++){
+                    if (s->lines[r]->dirty){
+                        for (size_t c = 0; c < s->ncol; c++){
+                            printf("contents of %zd,%zd: %lc (%s bold)\n", r, c,
+                                   s->lines[r]->chars[c].c,
+                                   s->lines[r]->chars[c].a.bold? "is" : "is not");
+                        }
+                    }
+                }
+
+                /* let tmt know we've redrawn the screen */
+                tmt_clean(vt);
+                break;
+
+            case TMT_MSG_ANSWER:
+                /* the terminal has a response to give to the program; a is a
+                 * pointer to a string */
+                printf("terminal answered %s\n", (const char *)a);
+                break;
+
+            case TMT_MSG_MOVED:
+                /* the cursor moved; a is a pointer to the cursor's TMTPOINT */
+                printf("cursor is now at %zd,%zd\n", c->r, c->c);
+                break;
+        }
+    }
+
+Data Types and Enumerations
+---------------------------
+
+.. code:: c
+
+    /* an opaque structure */
+    typedef struct TMT TMT;
+
+    /* possible messages sent to the callback */
+    typedef enum{
+        TMT_MSG_MOVED,  /* the cursor changed position       */
+        TMT_MSG_UPDATE, /* the screen image changed          */
+        TMT_MSG_ANSWER, /* the terminal responded to a query */
+        TMT_MSG_BELL    /* the terminal bell was rung        */
+    } tmt_msg_T;
+
+    /* a callback for the library
+     * m is one of the message constants above
+     * vt is a pointer to the vt structure
+     * r is NULL for TMT_MSG_BELL
+     *   is a pointer to the cursor's TMTPOINT for TMT_MSG_MOVED
+     *   is a pointer to the terminal's TMTSCREEN for TMT_MSG_UPDATE
+     *   is a pointer to a string for TMT_MSG_ANSWER
+     * p is whatever was passed to tmt_open (see below).
+     */
+    typedef void (*TMTCALLBACK)(tmt_msg_t m, struct TMT *vt,
+                                const void *r, void *p);
+
+    /* color definitions */
+    typedef enum{
+        TMT_COLOR_BLACK,
+        TMT_COLOR_RED,
+        TMT_COLOR_GREEN,
+        TMT_COLOR_YELLOW,
+        TMT_COLOR_BLUE,
+        TMT_COLOR_MAGENTA,
+        TMT_COLOR_CYAN,
+        TMT_COLOR_WHITE,
+        TMT_COLOR_DEFAULT /* whatever the host terminal wants it to mean */
+    } tmt_color_t;
+
+    /* graphical rendition */
+    typedef struct TMTATTRS TMTATTRS;
+    struct TMTATTRS{
+        bool bold;      /* character is bold             */
+        bool dim;       /* character is half-bright      */
+        bool underline; /* character is underlined       */
+        bool blink;     /* character is blinking         */
+        bool reverse;   /* character is in reverse video */
+        bool invisible; /* character is invisible        */
+        tmt_color_t fg; /* character foreground color    */
+        tmt_color_t bg; /* character background color    */
+    };
+
+    /* characters */
+    typedef struct TMTCHAR TMTCHAR;
+    struct TMTCHAR{
+        wchar_t  c; /* the character */
+        TMTATTRS a; /* its rendition */
+    };
+
+    /* a position on the screen; upper left corner is 0,0 */
+    typedef struct TMTPOINT TMTPOINT;
+    struct TMTPOINT{
+        size_t r; /* row    */
+        size_t c; /* column */
+    };
+
+    /* a line of characters on the screen;
+     * every line is always as wide as the screen
+     */
+    typedef struct TMTLINE TMTLINE;
+    struct TMTLINE{
+        bool dirty;     /* line has changed since it was last drawn */
+        TMTCHAR chars;  /* the contents of the line                 */
+    };
+
+    /* a virtual terminal screen image */
+    typedef struct TMTSCREEN TMTSCREEN;
+    struct TMTSCREEN{
+        size_t nline;    /* number of rows          */
+        size_t ncol;     /* number of columns       */
+        TMTLINE **lines; /* the lines on the screen */
+    };
+
+Functions
+---------
+
+`TMT *tmt_open(size_t nrows, size_t ncols, TMTCALLBACK cb, VOID *p, const wchar *acs);`
+    Creates a new virtual terminal, with `nrows` rows and `ncols` columns.
+    The callback `cb` will be called on updates, and passed `p` as a final
+    argument. See the definition of `tmt_msg_t` above for possible values
+    of each argument to the callback.
+
+    Terminals must have a size of at least two rows and two columns.
+
+    `acs` specifies the characters to use when in Alternate Character Set
+    (ACS) mode. The default string (used if `NULL` is specified) is::
+
+         L"><^v#+:o##+++++~---_++++|<>*!fo"
+
+    See `Alternate Character Set`_ for more information.
+
+    Note that the callback must be ready to be called immediately, as
+    it will be called after initialization of the terminal is done, but
+    before the call to `tmt_open` returns.
+
+`void tmt_close(TMT *vt)`
+    Close and free all resources associated with `vt`.
+
+`bool tmt_resize(TMT *vt, size_t nrows, size_t ncols)`
+    Resize the virtual terminal to have `nrows` rows and `ncols` columns.
+    The contents of the area in common between the two sizes will be preserved.
+
+    Terminals must have a size of at least two rows and two columns.
+
+    If this function returns false, the resize failed (only possible in
+    out-of-memory conditions or invalid sizes). If this happens, the terminal
+    is trashed and the only valid operation is the close the terminal.
+
+`void tmt_write(TMT *vt, const char *s, size_t n);`
+    Write the provided string to the terminal, interpreting any escape
+    sequences contained threin, and update the screen image. The last
+    argument is the length of the input. If set to 0, the length is
+    determined using `strlen`.
+
+    The terminal's callback function may be invoked one or more times before
+    a call to this function returns.
+
+    The string is converted internally to a wide-character string using the
+    system's current multibyte encoding. Each terminal maintains a private
+    multibyte decoding state, and correctly handles mulitbyte characters that
+    span multiple calls to this function (that is, the final byte(s) of `s`
+    may be a partial mulitbyte character to be completed on the next call).
+
+`const TMTSCREEN *tmt_screen(const TMT *vt);`
+    Returns a pointer to the terminal's screen image.
+
+`const TMTPOINT *tmt_cursor(cosnt TMT *vt);`
+    Returns a pointer to the terminal's cursor position.
+
+`void tmt_clean(TMT *vt);`
+    Call this after receiving a `TMT_MSG_UPDATE` or `TMT_MSG_MOVED` callback
+    to let the library know that the program has handled all reported changes
+    to the screen image.
+
+`void tmt_reset(TMT *vt);`
+    Resets the virtual terminal to its default state (colors, multibyte
+    decoding state, rendition, etc).
+
+Special Keys
+------------
+
+To send special keys to a program that is using libtmt for its display,
+write one of the `TMT_KEY_*` strings to that program's standard input
+(*not* to libtmt; it makes no sense to send any of these constants to
+libtmt itself).
+
+The following macros are defined, and are all constant strings:
+
+- TMT_KEY_UP
+- TMT_KEY_DOWN
+- TMT_KEY_RIGHT
+- TMT_KEY_LEFT
+- TMT_KEY_HOME
+- TMT_KEY_END
+- TMT_KEY_INSERT
+- TMT_KEY_BACKSPACE
+- TMT_KEY_ESCAPE
+- TMT_KEY_BACK_TAB
+- TMT_KEY_PAGE_UP
+- TMT_KEY_PAGE_DOWN
+- TMT_KEY_F1 through TMT_KEY_F10
+
+Note also that the classic PC console sent the enter key as
+a carriage return, not a linefeed. Many programs don't care,
+but some do.
+
+Compile-Time Options
+--------------------
+
+There are two preprocessor macros that affect libtmt:
+
+`TMT_INVALID_CHAR`
+    Define this to a wide-character. This character will be added to
+    the virtual display when an invalid multibyte character sequence
+    is encountered.
+
+    By default (if you don't define it as something else before compiling),
+    this is `((wchar_t)0xfffd)`, which is the codepoint for the Unicode
+    'REPLACEMENT CHARACTER'. Note that your system might not use Unicode,
+    and its wide-character type might not be able to store a constant as
+    large as `0xfffd`, in which case you'll want to use an alternative.
+
+`TMT_HAS_WCWIDTH`
+    By default, libtmt uses only standard C99 features.  If you define
+    TMT_HAS_WCWIDTH before compiling, libtmt will use the POSIX `wcwidth`
+    function to detect combining characters.
+
+    Note that combining characters are still not handled particularly
+    well, regardless of whether this was defined. Also note that what
+    your C library's `wcwidth` considers a combining character and what
+    the written language in question considers one could be different.
+
+Alternate Character Set
+-----------------------
+
+The terminal can be switched to and from its "Alternate Character Set" (ACS)
+using escape sequences. The ACS traditionally contained box-drawing and other
+semigraphic characters.
+
+The characters in the ACS are configurable at runtime, by passing a wide string
+to `tmt_open`. The default if none is provided (i.e. the argument is `NULL`)
+uses ASCII characters to approximate the traditional characters.
+
+The string passed to `tmt_open` must be 31 characters long. The characters,
+and their default ASCII-safe values, are in order:
+
+- RIGHT ARROW ">"
+- LEFT ARROW "<"
+- UP ARROW "^"
+- DOWN ARROW "v"
+- BLOCK "#"
+- DIAMOND "+"
+- CHECKERBOARD "#"
+- DEGREE "o"
+- PLUS/MINUS "+"
+- BOARD ":"
+- LOWER RIGHT CORNER "+"
+- UPPER RIGHT CORNER "+"
+- UPPER LEFT CORNER "+"
+- LOWER LEFT CORNER "+"
+- CROSS "+"
+- SCAN LINE 1 "~"
+- SCAN LINE 3 "-"
+- HORIZONTAL LINE "-"
+- SCAN LINE 7 "-"
+- SCAN LINE 9 "_"
+- LEFT TEE "+"
+- RIGHT TEE "+"
+- BOTTOM TEE "+"
+- TOP TEE "+"
+- VERTICAL LINE "|"
+- LESS THAN OR EQUAL "<"
+- GREATER THAN OR EQUAL ">"
+- PI "*"
+- NOT EQUAL "!"
+- POUND STERLING "f"
+- BULLET "o"
+
+If your system's wide character type's character set corresponds to the
+Universal Character Set (UCS/Unicode), the following wide string is a
+good option to use::
+
+    L"→←↑↓■◆▒°±▒┘┐┌└┼⎺───⎽├┤┴┬│≤≥π≠£•"
+
+**Note that multibyte decoding is disabled in ACS mode.** The traditional
+implementations of the "ansi" terminal type (i.e. IBM PCs and compatibles)
+had no concept of multibyte encodings and used the character codes
+outside the ASCII range for various special semigraphic characters.
+(Technically they had an entire alternate character set as well via the
+code page mechanism, but that's beyond the scope of this explanation.)
+
+The end result is that the terminfo definition of "ansi" sends characters
+with the high bit set when in ACS mode. This breaks several multibyte
+encoding schemes (including, most importantly, UTF-8).
+
+As a result, libtmt does not attempt to decode multibyte characters in
+ACS mode, since that would break the multibyte encoding, the semigraphic
+characters, or both.
+
+In general this isn't a problem, since programs explicitly switch to and
+from ACS mode using escape sequences.
+
+When in ACS mode, bytes that are not special members of the alternate
+character set (that is, bytes not mapped to the string provided to
+`tmt_open`) are passed unchanged to the terminal.
+
+Supported Input and Escape Sequences
+====================================
+
+Internally libtmt uses your C library's/compiler's idea of a wide character
+for all characters, so you should be able to use whatever characters you want
+when writing to the virtual terminal (but see `Alternate Character Set`_).
+
+The following escape sequences are recognized and will be processed
+specially.
+
+In the descriptions below, "ESC" means a literal escape character and "Ps"
+means zero or more decimal numeric arguments separated by semicolons.
+In descriptions "P1", "P2", etc, refer to the first parameter, second
+parameter, and so on.  If a required parameter is omitted, it defaults
+to the smallest meaningful value (zero if the command accepts zero as
+an argument, one otherwise).  Any number of parameters may be passed,
+but any after the first eight are ignored.
+
+Unless explicitly stated below, cursor motions past the edges of the screen
+are ignored and do not result in scrolling.  When characters are moved,
+the spaces left behind are filled with blanks and any characters moved
+off the edges of the screen are lost.
+
+======================  ======================================================================
+Sequence                Action
+======================  ======================================================================
+0x07 (Bell)             Callback with TMT_MSG_BELL
+0x08 (Backspace)        Cursor left one cell
+0x09 (Tab)              Cursor to next tab stop or end of line
+0x0a (Carriage Return)  Cursor to first cell on this line
+0x0d (Linefeed)         Cursor to same column one line down, scroll if needed
+ESC H                   Set a tabstop in this column
+ESC 7                   Save cursor position and current graphical state
+ESC 8                   Restore saved cursor position and current graphical state
+ESC c                   Reset terminal to default state
+ESC [ Ps A              Cursor up P1 rows
+ESC [ Ps B              Cursor down P1 rows
+ESC [ Ps C              Cursor right P1 columns
+ESC [ Ps D              Cursor left P1 columns
+ESC [ Ps E              Cursor to first column of line P1 rows down from current
+ESC [ Ps F              Cursor to first column of line P1 rows up from current
+ESC [ Ps G              Cursor to column P1
+ESC [ Ps d              Cursor to row P1
+ESC [ Ps H              Cursor to row P1, column P2
+ESC [ Ps f              Alias for ESC [ Ps H
+ESC [ Ps I              Cursor to next tab stop
+ESC [ Ps J              Clear screen
+                        P1 == 0: from cursor to end of screen
+                        P1 == 1: from beginning of screen to cursor
+                        P1 == 2: entire screen
+ESC [ Ps K              Clear line
+                        P1 == 0: from cursor to end of line
+                        P1 == 1: from beginning of line to cursor
+                        P1 == 2: entire line
+ESC [ Ps L              Insert P1 lines at cursor, scrolling lines below down
+ESC [ Ps M              Delete P1 lines at cursor, scrolling lines below up
+ESC [ Ps P              Delete P1 characters at cursor, moving characters to the right over
+ESC [ Ps S              Scroll screen up P1 lines
+ESC [ Ps T              Scroll screen down P1 lines
+ESC [ Ps X              Erase P1 characters at cursor (overwrite with spaces)
+ESC [ Ps Z              Go to previous tab stop
+ESC [ Ps b              Repeat previous character P1 times
+ESC [ Ps c              Callback with TMT_MSG_ANSWER "\033[?6c"
+ESC [ Ps g              If P1 == 3, clear all tabstops
+ESC [ Ps h              If P1 == 25, show the cursor (if it was hidden)
+ESC [ Ps m              Change graphical rendition state; see below
+ESC [ Ps l              If P1 == 25, hide the cursor
+ESC [ Ps n              If P1 == 6, callback with TMT_MSG_ANSWER "\033[%d;%dR"
+                        with cursor row, column
+ESC [ Ps s              Alias for ESC 7
+ESC [ Ps u              Alias for ESC 8
+ESC [ Ps @              Insert P1 blank spaces at cursor, moving characters to the right over
+======================  ======================================================================
+
+For the `ESC [ Ps m` escape sequence above ("Set Graphic Rendition"),
+up to eight parameters may be passed; the results are cumulative:
+
+==============   =================================================
+Rendition Code   Meaning
+==============   =================================================
+0                Reset all graphic rendition attributes to default
+1                Bold
+2                Dim (half bright)
+4                Underline
+5                Blink
+7                Reverse video
+8                Invisible
+10               Leave ACS mode
+11               Enter ACS mode
+22               Bold off
+23               Dim (half bright) off
+24               Underline off
+25               Blink off
+27               Reverse video off
+28               Invisible off
+30               Foreground black
+31               Foreground red
+32               Foreground green
+33               Foreground yellow
+34               Foreground blue
+35               Foreground magenta
+36               Foreground cyan
+37               Foreground white
+39               Foreground default color
+40               Background black
+41               Background red
+42               Background green
+43               Background yellow
+44               Background blue
+45               Background magenta
+46               Background cyan
+47               Background white
+49               Background default color
+==============   =================================================
+
+Other escape sequences are recognized but ignored.  This includes escape
+sequences for switching out codesets (officially, all code sets are defined
+as equivalent in libtmt), and the various "Media Copy" escape sequences
+used to print output on paper (officially, there is no printer attached
+to libtmt).
+
+Additionally, "?" characters are stripped out of escape sequence parameter
+lists for compatibility purposes.
+
+Known Issues
+============
+
+- Combining characters are "handled" by ignoring them
+  (when compiled with `TMT_HAS_WCWIDTH`) or by printing them separately.
+- Double-width characters are rendered as single-width invalid
+  characters.
+- The documentation and error messages are available only in English.
+
+Frequently Asked Questions
+==========================
+
+What programs work with libtmt?
+-------------------------------
+
+Pretty much all of them.  Any program that doesn't assume what terminal
+it's running under should work without problem; this includes any program
+that uses the terminfo, termcap, or (pd|n)?curses libraries.  Any program
+that assumes it's running under some specific terminal might fail if its
+assumption is wrong, and not just under libtmt.
+
+I've tested quite a few applications in libtmt and they've worked flawlessly:
+vim, GNU emacs, nano, cmus, mc (Midnight Commander), and others just work
+with no changes.
+
+What programs don't work with libtmt?
+-------------------------------------
+
+Breakage with libtmt is of two kinds: breakage due to assuming a terminal
+type, and reduced functionality.
+
+In all my testing, I only found one program that didn't work correctly by
+default with libtmt: recent versions of Debian's `apt`_ assume a terminal
+with definable scrolling regions to draw a fancy progress bar during
+package installation.  Using apt in its default configuration in libtmt will
+result in a corrupted display (that can be fixed by clearing the screen).
+
+.. _`apt`: https://wiki.debian.org/Apt
+
+In my honest opinion, this is a bug in apt: it shouldn't assume the type
+of terminal it's running in.
+
+The second kind of breakage is when not all of a program's features are
+available.  The biggest missing feature here is mouse support: libtmt
+doesn't, and probably never will, support mouse tracking.  I know of many
+programs that *can* use mouse tracking in a terminal, but I don't know
+of any that *require* it.  Most (if not all?) programs of this kind would
+still be completely usable in libtmt.
+
+License
+-------
+
+Copyright (c) 2017 Rob King
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+- Redistributions of source code must retain the above copyright
+  notice, this list of conditions and the following disclaimer.
+- Redistributions in binary form must reproduce the above copyright
+  notice, this list of conditions and the following disclaimer in the
+  documentation and/or other materials provided with the distribution.
+- Neither the name of the copyright holder nor the
+  names of contributors may be used to endorse or promote products
+  derived from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS,
+COPYRIGHT HOLDERS, OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/vendor/libtmt/tmt.c b/vendor/libtmt/tmt.c
new file mode 100644
index 00000000..73be670d
--- /dev/null
+++ b/vendor/libtmt/tmt.c
@@ -0,0 +1,506 @@
+/* Copyright (c) 2017 Rob King
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *   * Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ *   * Neither the name of the copyright holder nor the
+ *     names of contributors may be used to endorse or promote products
+ *     derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS,
+ * COPYRIGHT HOLDERS, OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+#include <limits.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include "tmt.h"
+
+#define BUF_MAX 100
+#define PAR_MAX 8
+#define TAB 8
+#define MAX(x, y) (((size_t)(x) > (size_t)(y)) ? (size_t)(x) : (size_t)(y))
+#define MIN(x, y) (((size_t)(x) < (size_t)(y)) ? (size_t)(x) : (size_t)(y))
+#define CLINE(vt) (vt)->screen.lines[MIN((vt)->curs.r, (vt)->screen.nline - 1)]
+
+#define P0(x) (vt->pars[x])
+#define P1(x) (vt->pars[x]? vt->pars[x] : 1)
+#define CB(vt, m, a) ((vt)->cb? (vt)->cb(m, vt, a, (vt)->p) : (void)0)
+#define INESC ((vt)->state)
+
+#define COMMON_VARS             \
+    TMTSCREEN *s = &vt->screen; \
+    TMTPOINT *c = &vt->curs;    \
+    TMTLINE *l = CLINE(vt);     \
+    TMTCHAR *t = vt->tabs->chars; \
+    /* ignore -Wunused-variable */ (void)t;(void)l;(void)c;(void)s
+
+#define HANDLER(name) static void name (TMT *vt) { COMMON_VARS; 
+
+struct TMT{
+    TMTPOINT curs, oldcurs;
+    TMTATTRS attrs, oldattrs;
+
+    bool dirty, acs, ignored;
+    TMTSCREEN screen;
+    TMTLINE *tabs;
+
+    TMTCALLBACK cb;
+    void *p;
+    const wchar_t *acschars;
+
+    mbstate_t ms;
+    size_t nmb;
+    char mb[BUF_MAX + 1];
+
+    size_t pars[PAR_MAX];   
+    size_t npar;
+    size_t arg;
+    enum {S_NUL, S_ESC, S_ARG} state;
+};
+
+static TMTATTRS defattrs = {.fg = TMT_COLOR_DEFAULT, .bg = TMT_COLOR_DEFAULT};
+static void writecharatcurs(TMT *vt, wchar_t w);
+
+static wchar_t
+tacs(const TMT *vt, unsigned char c)
+{
+    /* The terminfo alternate character set for ANSI. */
+    static unsigned char map[] = {0020U, 0021U, 0030U, 0031U, 0333U, 0004U,
+                                  0261U, 0370U, 0361U, 0260U, 0331U, 0277U,
+                                  0332U, 0300U, 0305U, 0176U, 0304U, 0304U,
+                                  0304U, 0137U, 0303U, 0264U, 0301U, 0302U,
+                                  0263U, 0363U, 0362U, 0343U, 0330U, 0234U,
+                                  0376U};
+    for (size_t i = 0; i < sizeof(map); i++) if (map[i] == c)
+        return vt->acschars[i];
+    return (wchar_t)c;
+}
+
+static void
+dirtylines(TMT *vt, size_t s, size_t e)
+{
+    vt->dirty = true;
+    for (size_t i = s; i < e; i++)
+        vt->screen.lines[i]->dirty = true;
+}
+
+static void
+clearline(TMT *vt, TMTLINE *l, size_t s, size_t e)
+{
+    vt->dirty = l->dirty = true;
+    for (size_t i = s; i < e && i < vt->screen.ncol; i++){
+        l->chars[i].a = defattrs;
+        l->chars[i].c = L' ';
+    }
+}
+
+static void
+clearlines(TMT *vt, size_t r, size_t n)
+{
+    for (size_t i = r; i < r + n && i < vt->screen.nline; i++)
+        clearline(vt, vt->screen.lines[i], 0, vt->screen.ncol);
+}
+
+static void
+scrup(TMT *vt, size_t r, size_t n)
+{
+    n = MIN(n, vt->screen.nline - 1 - r);
+
+    if (n){
+        TMTLINE *buf[n];
+
+        memcpy(buf, vt->screen.lines + r, n * sizeof(TMTLINE *));
+        memmove(vt->screen.lines + r, vt->screen.lines + r + n,
+                (vt->screen.nline - n - r) * sizeof(TMTLINE *));
+        memcpy(vt->screen.lines + (vt->screen.nline - n),
+               buf, n * sizeof(TMTLINE *));
+
+        clearlines(vt, vt->screen.nline - n, n);
+        dirtylines(vt, r, vt->screen.nline);
+    }
+}
+
+static void
+scrdn(TMT *vt, size_t r, size_t n)
+{
+    n = MIN(n, vt->screen.nline - 1 - r);
+
+    if (n){
+        TMTLINE *buf[n];
+
+        memcpy(buf, vt->screen.lines + (vt->screen.nline - n),
+               n * sizeof(TMTLINE *));
+        memmove(vt->screen.lines + r + n, vt->screen.lines + r,
+                (vt->screen.nline - n - r) * sizeof(TMTLINE *));
+        memcpy(vt->screen.lines + r, buf, n * sizeof(TMTLINE *));
+    
+        clearlines(vt, r, n);
+        dirtylines(vt, r, vt->screen.nline);
+    }
+}
+
+HANDLER(ed)
+    size_t b = 0;
+    size_t e = s->nline;
+
+    switch (P0(0)){
+        case 0: b = c->r + 1; clearline(vt, l, c->c, vt->screen.ncol); break;
+        case 1: e = c->r - 1; clearline(vt, l, 0, c->c);               break;
+        case 2:  /* use defaults */                                    break;
+        default: /* do nothing   */                                    return;
+    }
+
+    clearlines(vt, b, e - b);
+}
+
+HANDLER(ich)
+    size_t n = P1(0); /* XXX use MAX */
+    if (n > s->ncol - c->c - 1) n = s->ncol - c->c - 1;
+
+    memmove(l->chars + c->c + n, l->chars + c->c,
+            MIN(s->ncol - 1 - c->c,
+            (s->ncol - c->c - n - 1)) * sizeof(TMTCHAR));
+    clearline(vt, l, c->c, n);
+}
+
+HANDLER(dch)
+    size_t n = P1(0); /* XXX use MAX */
+    if (n > s->ncol - c->c) n = s->ncol - c->c;
+    else if (n == 0) return;
+
+    memmove(l->chars + c->c, l->chars + c->c + n,
+            (s->ncol - c->c - n) * sizeof(TMTCHAR));
+
+    clearline(vt, l, s->ncol - n, s->ncol);
+    /* VT102 manual says the attribute for the newly empty characters
+     * should be the same as the last character moved left, which isn't
+     * what clearline() currently does.
+     */
+}
+
+HANDLER(el)
+    switch (P0(0)){
+        case 0: clearline(vt, l, c->c, vt->screen.ncol);         break;
+        case 1: clearline(vt, l, 0, MIN(c->c + 1, s->ncol - 1)); break;
+        case 2: clearline(vt, l, 0, vt->screen.ncol);            break;
+    }
+}
+
+HANDLER(sgr)
+    #define FGBG(c) *(P0(i) < 40? &vt->attrs.fg : &vt->attrs.bg) = c
+    for (size_t i = 0; i < vt->npar; i++) switch (P0(i)){
+        case  0: vt->attrs                    = defattrs;   break;
+        case  1: case 22: vt->attrs.bold      = P0(0) < 20; break;
+        case  2: case 23: vt->attrs.dim       = P0(0) < 20; break;
+        case  4: case 24: vt->attrs.underline = P0(0) < 20; break;
+        case  5: case 25: vt->attrs.blink     = P0(0) < 20; break;
+        case  7: case 27: vt->attrs.reverse   = P0(0) < 20; break;
+        case  8: case 28: vt->attrs.invisible = P0(0) < 20; break;
+        case 10: case 11: vt->acs             = P0(0) > 10; break;
+        case 30: case 40: FGBG(TMT_COLOR_BLACK);            break;
+        case 31: case 41: FGBG(TMT_COLOR_RED);              break;
+        case 32: case 42: FGBG(TMT_COLOR_GREEN);            break;
+        case 33: case 43: FGBG(TMT_COLOR_YELLOW);           break;
+        case 34: case 44: FGBG(TMT_COLOR_BLUE);             break;
+        case 35: case 45: FGBG(TMT_COLOR_MAGENTA);          break;
+        case 36: case 46: FGBG(TMT_COLOR_CYAN);             break;
+        case 37: case 47: FGBG(TMT_COLOR_WHITE);            break;
+        case 39: case 49: FGBG(TMT_COLOR_DEFAULT);          break;
+    }
+}
+
+HANDLER(rep)
+    if (!c->c) return;
+    wchar_t r = l->chars[c->c - 1].c;
+    for (size_t i = 0; i < P1(0); i++)
+        writecharatcurs(vt, r);
+}
+
+HANDLER(dsr)
+    char r[BUF_MAX + 1] = {0};
+    snprintf(r, BUF_MAX, "\033[%zd;%zdR", c->r + 1, c->c + 1);
+    CB(vt, TMT_MSG_ANSWER, (const char *)r);
+}
+
+HANDLER(resetparser)
+    memset(vt->pars, 0, sizeof(vt->pars));
+    vt->state = vt->npar = vt->arg = vt->ignored = (bool)0;
+}
+
+HANDLER(consumearg)
+    if (vt->npar < PAR_MAX)
+        vt->pars[vt->npar++] = vt->arg;
+    vt->arg = 0;
+}
+
+HANDLER(fixcursor)
+    c->r = MIN(c->r, s->nline - 1);
+    c->c = MIN(c->c, s->ncol - 1);
+}
+
+static bool
+handlechar(TMT *vt, char i)
+{
+    COMMON_VARS;
+
+    char cs[] = {i, 0};
+    #define ON(S, C, A) if (vt->state == (S) && strchr(C, i)){ A; return true;}
+    #define DO(S, C, A) ON(S, C, consumearg(vt); if (!vt->ignored) {A;} \
+                                 fixcursor(vt); resetparser(vt););
+
+    DO(S_NUL, "\x07",       CB(vt, TMT_MSG_BELL, NULL))
+    DO(S_NUL, "\x08",       if (c->c) c->c--)
+    DO(S_NUL, "\x09",       while (++c->c < s->ncol - 1 && t[c->c].c != L'*'))
+    DO(S_NUL, "\x0a",       c->r < s->nline - 1? (void)c->r++ : scrup(vt, 0, 1))
+    DO(S_NUL, "\x0d",       c->c = 0)
+    ON(S_NUL, "\x1b",       vt->state = S_ESC)
+    ON(S_ESC, "\x1b",       vt->state = S_ESC)
+    DO(S_ESC, "H",          t[c->c].c = L'*')
+    DO(S_ESC, "7",          vt->oldcurs = vt->curs; vt->oldattrs = vt->attrs)
+    DO(S_ESC, "8",          vt->curs = vt->oldcurs; vt->attrs = vt->oldattrs)
+    ON(S_ESC, "+*()",       vt->ignored = true; vt->state = S_ARG)
+    DO(S_ESC, "c",          tmt_reset(vt))
+    ON(S_ESC, "[",          vt->state = S_ARG)
+    ON(S_ARG, "\x1b",       vt->state = S_ESC)
+    ON(S_ARG, ";",          consumearg(vt))
+    ON(S_ARG, "?",          (void)0)
+    ON(S_ARG, "0123456789", vt->arg = vt->arg * 10 + atoi(cs))
+    DO(S_ARG, "A",          c->r = MAX(c->r - P1(0), 0))
+    DO(S_ARG, "B",          c->r = MIN(c->r + P1(0), s->nline - 1))
+    DO(S_ARG, "C",          c->c = MIN(c->c + P1(0), s->ncol - 1))
+    DO(S_ARG, "D",          c->c = MIN(c->c - P1(0), c->c))
+    DO(S_ARG, "E",          c->c = 0; c->r = MIN(c->r + P1(0), s->nline - 1))
+    DO(S_ARG, "F",          c->c = 0; c->r = MAX(c->r - P1(0), 0))
+    DO(S_ARG, "G",          c->c = MIN(P1(0) - 1, s->ncol - 1))
+    DO(S_ARG, "d",          c->r = MIN(P1(0) - 1, s->nline - 1))
+    DO(S_ARG, "Hf",         c->r = P1(0) - 1; c->c = P1(1) - 1)
+    DO(S_ARG, "I",          while (++c->c < s->ncol - 1 && t[c->c].c != L'*'))
+    DO(S_ARG, "J",          ed(vt))
+    DO(S_ARG, "K",          el(vt))
+    DO(S_ARG, "L",          scrdn(vt, c->r, P1(0)))
+    DO(S_ARG, "M",          scrup(vt, c->r, P1(0)))
+    DO(S_ARG, "P",          dch(vt))
+    DO(S_ARG, "S",          scrup(vt, 0, P1(0)))
+    DO(S_ARG, "T",          scrdn(vt, 0, P1(0)))
+    DO(S_ARG, "X",          clearline(vt, l, c->c, P1(0)))
+    DO(S_ARG, "Z",          while (c->c && t[--c->c].c != L'*'))
+    DO(S_ARG, "b",          rep(vt));
+    DO(S_ARG, "c",          CB(vt, TMT_MSG_ANSWER, "\033[?6c"))
+    DO(S_ARG, "g",          if (P0(0) == 3) clearline(vt, vt->tabs, 0, s->ncol))
+    DO(S_ARG, "m",          sgr(vt))
+    DO(S_ARG, "n",          if (P0(0) == 6) dsr(vt))
+    DO(S_ARG, "h",          if (P0(0) == 25) CB(vt, TMT_MSG_CURSOR, "t"))
+    DO(S_ARG, "i",          (void)0)
+    DO(S_ARG, "l",          if (P0(0) == 25) CB(vt, TMT_MSG_CURSOR, "f"))
+    DO(S_ARG, "s",          vt->oldcurs = vt->curs; vt->oldattrs = vt->attrs)
+    DO(S_ARG, "u",          vt->curs = vt->oldcurs; vt->attrs = vt->oldattrs)
+    DO(S_ARG, "@",          ich(vt))
+
+    return resetparser(vt), false;
+}
+
+static void
+notify(TMT *vt, bool update, bool moved)
+{
+    if (update) CB(vt, TMT_MSG_UPDATE, &vt->screen);
+    if (moved) CB(vt, TMT_MSG_MOVED, &vt->curs);
+}
+
+static TMTLINE *
+allocline(TMT *vt, TMTLINE *o, size_t n, size_t pc)
+{
+    TMTLINE *l = realloc(o, sizeof(TMTLINE) + n * sizeof(TMTCHAR));
+    if (!l) return NULL;
+
+    clearline(vt, l, pc, n);
+    return l;
+}
+
+static void
+freelines(TMT *vt, size_t s, size_t n, bool screen)
+{
+    for (size_t i = s; vt->screen.lines && i < s + n; i++){
+        free(vt->screen.lines[i]);
+        vt->screen.lines[i] = NULL;
+    }
+    if (screen) free(vt->screen.lines);
+}
+
+TMT *
+tmt_open(size_t nline, size_t ncol, TMTCALLBACK cb, void *p,
+         const wchar_t *acs)
+{
+    TMT *vt = calloc(1, sizeof(TMT));
+    if (!nline || !ncol || !vt) return free(vt), NULL;
+
+    /* ASCII-safe defaults for box-drawing characters. */
+    vt->acschars = acs? acs : L"><^v#+:o##+++++~---_++++|<>*!fo";
+    vt->cb = cb;
+    vt->p = p;
+
+    if (!tmt_resize(vt, nline, ncol)) return tmt_close(vt), NULL;
+    return vt;
+}
+
+void
+tmt_close(TMT *vt)
+{
+    free(vt->tabs);
+    freelines(vt, 0, vt->screen.nline, true);
+    free(vt);
+}
+
+bool
+tmt_resize(TMT *vt, size_t nline, size_t ncol)
+{
+    if (nline < 2 || ncol < 2) return false;
+    if (nline < vt->screen.nline)
+        freelines(vt, nline, vt->screen.nline - nline, false);
+
+    TMTLINE **l = realloc(vt->screen.lines, nline * sizeof(TMTLINE *));
+    if (!l) return false;
+
+    size_t pc = vt->screen.ncol;
+    vt->screen.lines = l;
+    vt->screen.ncol = ncol;
+    for (size_t i = 0; i < nline; i++){
+        TMTLINE *nl = NULL;
+        if (i >= vt->screen.nline)
+            nl = vt->screen.lines[i] = allocline(vt, NULL, ncol, 0);
+        else
+            nl = allocline(vt, vt->screen.lines[i], ncol, pc);
+
+        if (!nl) return false;
+        vt->screen.lines[i] = nl;
+    }
+    vt->screen.nline = nline;
+
+    vt->tabs = allocline(vt, vt->tabs, ncol, 0);
+    if (!vt->tabs) return free(l), false;
+    vt->tabs->chars[0].c = vt->tabs->chars[ncol - 1].c = L'*';
+    for (size_t i = 0; i < ncol; i++) if (i % TAB == 0)
+        vt->tabs->chars[i].c = L'*';
+
+    fixcursor(vt);
+    dirtylines(vt, 0, nline);
+    notify(vt, true, true);
+    return true;
+}
+
+static void
+writecharatcurs(TMT *vt, wchar_t w)
+{
+    COMMON_VARS;
+
+    #ifdef TMT_HAS_WCWIDTH
+    extern int wcwidth(wchar_t c);
+    if (wcwidth(w) > 1)  w = TMT_INVALID_CHAR;
+    if (wcwidth(w) < 0) return;
+    #endif
+
+    CLINE(vt)->chars[vt->curs.c].c = w;
+    CLINE(vt)->chars[vt->curs.c].a = vt->attrs;
+    CLINE(vt)->dirty = vt->dirty = true;
+
+    if (c->c < s->ncol - 1)
+        c->c++;
+    else{
+        c->c = 0;
+        c->r++;
+    }
+
+    if (c->r >= s->nline){
+        c->r = s->nline - 1;
+        scrup(vt, 0, 1);
+    }
+}
+
+static inline size_t
+testmbchar(TMT *vt)
+{
+    mbstate_t ts = vt->ms;
+    return vt->nmb? mbrtowc(NULL, vt->mb, vt->nmb, &ts) : (size_t)-2;
+}
+
+static inline wchar_t
+getmbchar(TMT *vt)
+{
+    wchar_t c = 0;
+    size_t n = mbrtowc(&c, vt->mb, vt->nmb, &vt->ms);
+    vt->nmb = 0;
+    return (n == (size_t)-1 || n == (size_t)-2)? TMT_INVALID_CHAR : c;
+}
+
+void
+tmt_write(TMT *vt, const char *s, size_t n)
+{
+    TMTPOINT oc = vt->curs;
+    n = n? n : strlen(s);
+
+    for (size_t p = 0; p < n; p++){
+        if (handlechar(vt, s[p]))
+            continue;
+        else if (vt->acs)
+            writecharatcurs(vt, tacs(vt, (unsigned char)s[p]));
+        else if (vt->nmb >= BUF_MAX)
+            writecharatcurs(vt, getmbchar(vt));
+        else{
+            switch (testmbchar(vt)){
+                case (size_t)-1: writecharatcurs(vt, getmbchar(vt)); break;
+                case (size_t)-2: vt->mb[vt->nmb++] = s[p];           break;
+            }
+
+            if (testmbchar(vt) <= MB_LEN_MAX)
+                writecharatcurs(vt, getmbchar(vt));
+        }
+    }
+
+    notify(vt, vt->dirty, memcmp(&oc, &vt->curs, sizeof(oc)) != 0);
+}
+
+const TMTSCREEN *
+tmt_screen(const TMT *vt)
+{
+    return &vt->screen;
+}
+
+const TMTPOINT *
+tmt_cursor(const TMT *vt)
+{
+    return &vt->curs;
+}
+
+void
+tmt_clean(TMT *vt)
+{
+    for (size_t i = 0; i < vt->screen.nline; i++)
+        vt->dirty = vt->screen.lines[i]->dirty = false;
+}
+
+void
+tmt_reset(TMT *vt)
+{
+    vt->curs.r = vt->curs.c = vt->oldcurs.r = vt->oldcurs.c = vt->acs = (bool)0;
+    resetparser(vt);
+    vt->attrs = vt->oldattrs = defattrs;
+    memset(&vt->ms, 0, sizeof(vt->ms));
+    clearlines(vt, 0, vt->screen.nline);
+    CB(vt, TMT_MSG_CURSOR, "t");
+    notify(vt, true, true);
+}
diff --git a/vendor/libtmt/tmt.h b/vendor/libtmt/tmt.h
new file mode 100644
index 00000000..ae0ddbb9
--- /dev/null
+++ b/vendor/libtmt/tmt.h
@@ -0,0 +1,140 @@
+/* Copyright (c) 2017 Rob King
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *   * Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ *   * Neither the name of the copyright holder nor the
+ *     names of contributors may be used to endorse or promote products
+ *     derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS,
+ * COPYRIGHT HOLDERS, OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef TMT_H
+#define TMT_H
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <wchar.h>
+
+/**** INVALID WIDE CHARACTER */
+#ifndef TMT_INVALID_CHAR
+#define TMT_INVALID_CHAR ((wchar_t)0xfffd)
+#endif
+
+/**** INPUT SEQUENCES */
+#define TMT_KEY_UP             "\033[A"
+#define TMT_KEY_DOWN           "\033[B"
+#define TMT_KEY_RIGHT          "\033[C"
+#define TMT_KEY_LEFT           "\033[D"
+#define TMT_KEY_HOME           "\033[H"
+#define TMT_KEY_END            "\033[Y"
+#define TMT_KEY_INSERT         "\033[L"
+#define TMT_KEY_BACKSPACE      "\x08"
+#define TMT_KEY_ESCAPE         "\x1b"
+#define TMT_KEY_BACK_TAB       "\033[Z"
+#define TMT_KEY_PAGE_UP        "\033[V"
+#define TMT_KEY_PAGE_DOWN      "\033[U"
+#define TMT_KEY_F1             "\033OP"
+#define TMT_KEY_F2             "\033OQ"
+#define TMT_KEY_F3             "\033OR"
+#define TMT_KEY_F4             "\033OS"
+#define TMT_KEY_F5             "\033OT"
+#define TMT_KEY_F6             "\033OU"
+#define TMT_KEY_F7             "\033OV"
+#define TMT_KEY_F8             "\033OW"
+#define TMT_KEY_F9             "\033OX"
+#define TMT_KEY_F10            "\033OY"
+
+/**** BASIC DATA STRUCTURES */
+typedef struct TMT TMT;
+
+typedef enum{
+    TMT_COLOR_DEFAULT = -1,
+    TMT_COLOR_BLACK = 1,
+    TMT_COLOR_RED,
+    TMT_COLOR_GREEN,
+    TMT_COLOR_YELLOW,
+    TMT_COLOR_BLUE,
+    TMT_COLOR_MAGENTA,
+    TMT_COLOR_CYAN,
+    TMT_COLOR_WHITE,
+    TMT_COLOR_MAX
+} tmt_color_t;
+
+typedef struct TMTATTRS TMTATTRS;
+struct TMTATTRS{
+    bool bold;
+    bool dim;
+    bool underline;
+    bool blink;
+    bool reverse;
+    bool invisible;
+    tmt_color_t fg;
+    tmt_color_t bg;
+};
+
+typedef struct TMTCHAR TMTCHAR;
+struct TMTCHAR{
+    wchar_t c;
+    TMTATTRS a;
+};
+
+typedef struct TMTPOINT TMTPOINT;
+struct TMTPOINT{
+    size_t r;
+    size_t c;
+};
+
+typedef struct TMTLINE TMTLINE;
+struct TMTLINE{
+    bool dirty;
+    TMTCHAR chars[];
+};
+
+typedef struct TMTSCREEN TMTSCREEN;
+struct TMTSCREEN{
+    size_t nline;
+    size_t ncol;
+
+    TMTLINE **lines;
+};
+
+/**** CALLBACK SUPPORT */
+typedef enum{
+    TMT_MSG_MOVED,
+    TMT_MSG_UPDATE,
+    TMT_MSG_ANSWER,
+    TMT_MSG_BELL,
+    TMT_MSG_CURSOR
+} tmt_msg_t;
+
+typedef void (*TMTCALLBACK)(tmt_msg_t m, struct TMT *v, const void *r, void *p);
+
+/**** PUBLIC FUNCTIONS */
+TMT *tmt_open(size_t nline, size_t ncol, TMTCALLBACK cb, void *p,
+              const wchar_t *acs);
+void tmt_close(TMT *vt);
+bool tmt_resize(TMT *vt, size_t nline, size_t ncol);
+void tmt_write(TMT *vt, const char *s, size_t n);
+const TMTSCREEN *tmt_screen(const TMT *vt);
+const TMTPOINT *tmt_cursor(const TMT *vt);
+void tmt_clean(TMT *vt);
+void tmt_reset(TMT *vt);
+
+#endif
diff --git a/virtual-programs/apriltags.folk b/virtual-programs/apriltags.folk
index 01377b78..ac2c4f8b 100644
--- a/virtual-programs/apriltags.folk
+++ b/virtual-programs/apriltags.folk
@@ -1,6 +1,7 @@
 if {$::isLaptop} return
 
-On process {
+# Plain detector. Runs on entire camera frame.
+set mainDetectorProcess [On process {
     source pi/AprilTags.tcl
     AprilTags::init
 
@@ -9,29 +10,131 @@ On process {
     Retract /anyone/ wishes $::thisProcess shares all wishes
     Retract /anyone/ wishes $::thisProcess shares all claims
     Wish $::thisProcess receives statements like \
-        [list /someone/ claims the camera frame is /grayFrame/]
+        [list /someone/ claims the camera frame is /grayFrame/ at /timestamp/]
     Wish $::thisProcess shares statements like \
         [list /someone/ wishes /process/ receives statements like /pattern/]
     Wish $::thisProcess shares statements like \
-        [list /someone/ claims tag /tag/ has center /center/ size /size/]
-    Wish $::thisProcess shares statements like \
-        [list /someone/ claims tag /tag/ has corners /corners/]
-    Wish $::thisProcess shares statements like \
-        [list /someone/ claims the AprilTag time is /aprilTime/]
+        [list /someone/ claims /process/ detects tags /tags/ at /timestamp/ in time /aprilTime/]
     Wish $::thisProcess shares statements like \
         [list /someone/ claims $::thisProcess has pid /pid/]
 
-    When the camera frame is /grayFrame/ {
+    When the camera frame is /grayFrame/ at /timestamp/ {
         set aprilTime [time {
             set tags [AprilTags::detect $grayFrame]
         }]
-        Commit {
-            Claim the AprilTag time is $aprilTime
+        Claim $::thisProcess detects tags $tags at $timestamp in time $aprilTime
+    }
+}]
+
+# Incremental detector. Looks at regions where there were tags in the
+# old camera frame.
+On process {
+    source pi/AprilTags.tcl
+    AprilTags::init
 
-            foreach tag $tags {
-                Claim tag [dict get $tag id] has center [dict get $tag center] size [dict get $tag size]
-                Claim tag [dict get $tag id] has corners [dict get $tag corners]
+    # TODO: Clean this up. We retract these so that we don't bounce
+    # statements back to the main Folk process that it sends us.
+    Retract /anyone/ wishes $::thisProcess shares all wishes
+    Retract /anyone/ wishes $::thisProcess shares all claims
+    Wish $::thisProcess receives statements like \
+        [list /someone/ claims the camera frame is /grayFrame/ at /timestamp/]
+    Wish $::thisProcess receives statements like \
+        [list /someone/ claims $mainDetectorProcess detects tags /tags/ at /timestamp/ in time /aprilTime/]
+    Wish $::thisProcess shares statements like \
+        [list /someone/ wishes /process/ receives statements like /pattern/]
+    Wish $::thisProcess shares statements like \
+        [list /someone/ claims $::thisProcess has pid /pid/]
+    Wish $::thisProcess shares statements like \
+        [list /someone/ claims $::thisProcess detects tags /tags/ at /timestamp/ in time /aprilTime/]
+    Wish $::thisProcess shares statements like \
+        [list /someone/ wishes /something/ is labelled /text/]
+    Wish $::thisProcess shares statements like \
+        [list /someone/ wishes /something/ displays camera slice /slice/]
+
+    proc subimage {im x y subwidth subheight} {
+	dict with im {
+	    set x [expr {int($x)}]
+	    set y [expr {int($y)}]
+	    set subdata [expr {$data + ($y*$width + $x) * $components}]
+	    dict create \
+		width [int $subwidth] \
+		height [int $subheight] \
+		components $components \
+		bytesPerRow $bytesPerRow \
+		data [format 0x%x $subdata]
+	}
+    }
+
+    When the camera frame is /grayFrame/ at /timestamp/ & \
+         /process/ detects tags /prevTags/ at /something/ in time /something/ {
+
+        if {$process eq $::thisProcess} { return }
+
+        set tags [list]
+        set frameWidth [dict get $grayFrame width]
+        set frameHeight [dict get $grayFrame height]
+        set aprilTime 0
+        foreach prevTag $prevTags {
+            set size [dict get $prevTag size]
+            set corners [dict get $prevTag corners]
+            set x [min {*}[lmap corner $corners {lindex $corner 0}]]
+            set y [min {*}[lmap corner $corners {lindex $corner 1}]]
+            set x1 [max {*}[lmap corner $corners {lindex $corner 0}]]
+            set y1 [max {*}[lmap corner $corners {lindex $corner 1}]]
+            
+            set x [max [- $x $size] 0]
+            set y [max [- $y $size] 0]
+            set x1 [min [+ $x1 $size] $frameWidth]
+            set y1 [min [+ $y1 $size] $frameHeight]
+
+            set subimage [subimage $grayFrame $x $y [- $x1 $x] [- $y1 $y]]
+            set aprilTime [+ $aprilTime [baretime {
+                foreach tag [AprilTags::detect $subimage] {
+                    dict with tag {
+                        set center [vec2 add $center [list $x $y]]
+                        set corners [lmap corner $corners {vec2 add $corner [list $x $y]}]
+                    }
+                    lappend tags $tag
+                }
+            }]]
+        }
+
+        # Wish 6 is labelled "[llength $prevTags] -> [llength $tags] ($aprilTime us)"
+
+        Claim $::thisProcess detects tags $tags at $timestamp in time $aprilTime
+        # Wish 6 is labelled "\n\nStep time $::stepTime\n[join [lmap s [dict values [Statements::all]] {statement short $s}] "\n"]"
+    }
+}
+
+# This cache is used to remember the last seen position of each tag,
+# so that if the incremental detector blinks out, we still use the
+# tag's last-found position from it, instead of the older position
+# from the full detector, so as you move a tag its position doesn't
+# glitch backward.
+set ::tagsCache [dict create]
+# TODO: Garbage-collect this cache.
+
+When the collected matches for [list /someone/ detects tags /tags/ at /timestamp/ in time /aprilTime/] are /matches/ {
+    set tagsSeen [dict create]
+    foreach match $matches {
+        set timestamp [dict get $match timestamp]
+        foreach tag [dict get $match tags] {
+            set id [dict get $tag id]
+            dict set tag timestamp $timestamp
+
+            if {[dict exists $::tagsCache $id] &&
+                [dict get $::tagsCache $id timestamp] > $timestamp} {
+                set tag [dict get $::tagsCache $id]
+            } else {
+                dict set ::tagsCache $id $tag
             }
+            dict set tagsSeen $id $tag
         }
     }
+
+    dict for {id tag} $tagsSeen {
+        Claim tag $id has center [dict get $tag center] size [dict get $tag size]
+        Claim tag $id has corners [dict get $tag corners]
+    }
+    Claim the AprilTag time is [lmap m $matches {dict get $m aprilTime}]
 }
diff --git a/virtual-programs/camera.folk b/virtual-programs/camera.folk
index d9dab784..0a95c8f0 100644
--- a/virtual-programs/camera.folk
+++ b/virtual-programs/camera.folk
@@ -18,15 +18,18 @@ On process {
     source pi/Camera.tcl
     Camera::init $width $height
 
-    puts "Camera tid: [getTid]"
-    
-    forever {
-        set cameraTime [time {
-            set grayFrame [Camera::grayFrame]
-        }]
+    puts "Camera tid: [getTid] booting at [clock milliseconds]"
+
+    When $::thisProcess has step count /c/ {
+        set grayFrame [Camera::grayFrame]
         Commit {
-            Claim the camera time is $cameraTime
-            Claim the camera frame is $grayFrame
+            Claim the camera time is $::stepTime
+            Claim the camera frame is $grayFrame at [clock milliseconds]
         }
     }
 }
+
+# For backward compatibility.
+When the camera frame is /grayFrame/ at /timestamp/ {
+    Claim the camera frame is $grayFrame
+}
diff --git a/virtual-programs/display.folk b/virtual-programs/display.folk
new file mode 100644
index 00000000..d3f6b610
--- /dev/null
+++ b/virtual-programs/display.folk
@@ -0,0 +1,93 @@
+if {$::isLaptop} return
+
+namespace eval ::Display {
+    variable WIDTH
+    variable HEIGHT
+    variable LAYER 0
+    regexp {mode "(\d+)x(\d+)"} [exec fbset] -> WIDTH HEIGHT
+
+    proc drawOnTop {func args} {
+        set ::Display::LAYER 1
+        uplevel [list $func {*}$args]
+        set ::Display::LAYER 0
+    }
+
+    proc stroke {points width color} {
+        uplevel [list Wish display runs [list Display::stroke $points $width $color] on layer $::Display::LAYER]
+    }
+
+    proc circle {x y radius thickness color} {
+        uplevel [list Wish display runs [list Display::circle $x $y $radius $thickness $color] on layer $::Display::LAYER]
+    }
+
+    proc text args {
+        uplevel [list Wish display runs [list Display::text {*}$args] on layer $::Display::LAYER]
+    }
+
+    proc fillTriangle args {
+        uplevel [list Wish display runs [list Display::fillTriangle {*}$args] on layer $::Display::LAYER]
+    }
+
+    proc fillQuad args {
+        uplevel [list Wish display runs [list Display::fillQuad {*}$args] on layer $::Display::LAYER]
+    }
+
+    proc fillPolygon args {
+        uplevel [list Wish display runs [list Display::fillPolygon {*}$args] on layer $::Display::LAYER]
+    }
+
+    variable displayTime none
+}
+
+On process {
+    source pi/Display.tcl
+    Display::init
+    puts "Display tid: [getTid]"
+
+    # TODO: Clean this up. We retract these so that we don't bounce
+    # statements back to the main Folk process that it sends us.
+    Retract /anyone/ wishes $::thisProcess shares all wishes
+    Retract /anyone/ wishes $::thisProcess shares all claims
+    Wish $::thisProcess shares statements like \
+        [list /someone/ wishes /process/ receives statements like /pattern/]
+    Wish $::thisProcess shares statements like \
+        [list /someone/ claims $::thisProcess has pid /pid/]
+    Wish $::thisProcess receives statements like \
+        [list /someone/ wishes display runs /command/ on layer /layer/]
+    Wish $::thisProcess receives statements like \
+        [list /someone/ wishes display runs /command/]
+    Wish $::thisProcess shares statements like \
+        [list /someone/ claims the display time is /displayTime/]
+
+    while true {
+        set displayList [list]
+        foreach match [Statements::findMatches {/someone/ wishes display runs /command/ on layer /layer/}] {
+            lappend displayList [list [dict get $match layer] [dict get $match command]]
+        }
+        foreach match [Statements::findMatches {/someone/ wishes display runs /command/}] {
+            lappend displayList [list 0 [dict get $match command]]
+        }
+
+        proc lcomp {a b} {
+            set layerA [lindex $a 0]
+            set layerB [lindex $b 0]
+            if {$layerA == $layerB} {
+                expr {[lindex $a 1 0] == "Display::text"}
+            } else {
+                expr {$layerA - $layerB}
+            }
+        }
+
+        set displayCommands [lmap sublist [lsort -command lcomp $displayList] {lindex $sublist 1}]
+
+        set renderTime [baretime [list foreach command $displayCommands { {*}$command }]]
+        set commitTime [baretime commitThenClearStaging]
+
+        Commit { Claim the display time is "render $renderTime us + commit $commitTime us ($::stepTime)" }
+        Step
+    }
+}
+# TODO: remove this compatibility hack
+When the display time is /displayTime/ {
+    set ::Display::displayTime $displayTime
+}
diff --git a/virtual-programs/esc-restart.folk b/virtual-programs/esc-restart.folk
index 01a6dd94..ee8aa847 100644
--- a/virtual-programs/esc-restart.folk
+++ b/virtual-programs/esc-restart.folk
@@ -1,5 +1,3 @@
-When the keyboard character log is /k/ {
-	foreach press $k {
-		if {$press eq "esc"} {exec sudo systemctl restart folk}
-	}
-}
\ No newline at end of file
+When keyboard claims key ESC is down with modifiers alt {
+	exec sudo systemctl restart folk
+}
diff --git a/virtual-programs/images.folk b/virtual-programs/images.folk
index 6846975e..ee3988ea 100644
--- a/virtual-programs/images.folk
+++ b/virtual-programs/images.folk
@@ -32,6 +32,7 @@ namespace eval ::image {
     defineImageType $cc
     $cc include <stdlib.h>
     $cc include <string.h>
+    $cc import ::Heap::cc folkHeapAlloc as folkHeapAlloc
 
     $cc code {
         #undef EXTERN
@@ -40,18 +41,30 @@ namespace eval ::image {
         #include <unistd.h>
 
         void 
-    jpeg(FILE* dest, uint8_t* rgb, uint32_t width, uint32_t height, int quality)
+    jpeg(FILE* dest, uint8_t* data, uint32_t components, uint32_t width, uint32_t height, int quality)
     {
-      JSAMPARRAY image;
-      image = calloc(height, sizeof (JSAMPROW));
-      for (size_t i = 0; i < height; i++) {
-        image[i] = calloc(width * 3, sizeof (JSAMPLE));
-        for (size_t j = 0; j < width; j++) {
-          image[i][j * 3 + 0] = rgb[(i * width + j)];
-          image[i][j * 3 + 1] = rgb[(i * width + j)];
-          image[i][j * 3 + 2] = rgb[(i * width + j)];
+        JSAMPARRAY image;
+        if (components == 1) {
+            image = calloc(height, sizeof (JSAMPROW));
+            for (size_t i = 0; i < height; i++) {
+                image[i] = calloc(width * 3, sizeof (JSAMPLE));
+                for (size_t j = 0; j < width; j++) {
+                    image[i][j * 3 + 0] = data[(i * width + j)];
+                    image[i][j * 3 + 1] = data[(i * width + j)];
+                    image[i][j * 3 + 2] = data[(i * width + j)];
+                }
+            }
+        } else if (components == 3) {
+            image = calloc(height, sizeof (JSAMPROW));
+            for (size_t i = 0; i < height; i++) {
+                image[i] = calloc(width * 3, sizeof (JSAMPLE));
+                for (size_t j = 0; j < width; j++) {
+                    image[i][j * 3 + 0] = data[(i * width + j) * 3];
+                    image[i][j * 3 + 1] = data[(i * width + j) * 3 + 1];
+                    image[i][j * 3 + 2] = data[(i * width + j) * 3 + 2];
+                }
+            }
         }
-      }
 
       struct jpeg_compress_struct compress;
       struct jpeg_error_mgr error;
@@ -79,11 +92,103 @@ namespace eval ::image {
     }
     $cc proc saveAsJpeg {image_t im char* filename} void {
         FILE* out = fopen(filename, "w");
-        jpeg(out, im.data, im.width, im.height, 100);
+        jpeg(out, im.data, im.components, im.width, im.height, 100);
         fclose(out);
     }
+    # Given the four corners of a region in an image, warp it to a new image of a given width and height
+    $cc proc warp {image_t im uint32_t tl_x uint32_t tl_y uint32_t tr_x uint32_t tr_y uint32_t br_x uint32_t br_y uint32_t bl_x uint32_t bl_y uint32_t output_width uint32_t output_height} image_t {
+        image_t ret;
+        ret.width = output_width;
+        ret.height = output_height;
+        ret.components = im.components;
+        ret.bytesPerRow = ret.width * ret.components;
+        ret.data = folkHeapAlloc(ret.bytesPerRow * ret.height);
+
+        for (int y = 0; y < output_height; y++) {
+            for (int x = 0; x < output_width; x++) {
+                // calculate the position in the input image
+                float u = (float)x / (float)(output_width - 1);
+                float v = (float)y / (float)(output_height - 1);
+                int input_x = tl_x + u * (int)(tr_x - tl_x) + v * (int)(bl_x - tl_x);
+                int input_y = tl_y + u * (int)(tr_y - tl_y) + v * (int)(bl_y - tl_y);
+
+                if (input_x >= 0 && input_x < im.width && input_y >= 0 && input_y < im.height) {
+                    memcpy(&ret.data[y * ret.bytesPerRow + x * ret.components],
+                        &im.data[input_y * im.bytesPerRow + input_x * im.components],
+                        im.components);
+                }
+            }
+        }
+        return ret;
+    }
+    $cc proc loadJpeg {char* filename} image_t {
+        FILE* file = fopen(filename, "rb");
+        if (!file) {
+            fprintf(stderr, "Error opening file: %s\n", filename);
+            exit(1);
+        }
+        
+        struct jpeg_decompress_struct cinfo;
+        struct jpeg_error_mgr jerr;
+        
+        cinfo.err = jpeg_std_error(&jerr);
+        jpeg_create_decompress(&cinfo);
+        jpeg_stdio_src(&cinfo, file);
+        jpeg_read_header(&cinfo, TRUE);
+        jpeg_start_decompress(&cinfo);
+        
+        image_t ret;
+        ret.width = cinfo.output_width;
+        ret.height = cinfo.output_height;
+        ret.components = cinfo.output_components;
+        ret.bytesPerRow = ret.width * ret.components;
+        ret.data = folkHeapAlloc(ret.bytesPerRow * ret.height);
+        
+        JSAMPROW row_pointer[1];
+        while (cinfo.output_scanline < cinfo.output_height) {
+            row_pointer[0] = (JSAMPLE*)ret.data + cinfo.output_scanline * ret.bytesPerRow;
+            jpeg_read_scanlines(&cinfo, row_pointer, 1);
+        }
+        
+        jpeg_finish_decompress(&cinfo);
+        jpeg_destroy_decompress(&cinfo);
+        fclose(file);
+        
+        return ret;
+    }
+    $cc proc freeJpeg {image_t im} void {
+        // TODO: Free the JPEG.
+        // ckfree(im.data);
+    }
     $cc compile
 
+    variable imagesCache [dict create]
+    # Loads a URL or file path if passed. If passed a valid image_t,
+    # just returns that image_t.
+    proc load {im} {
+        variable imagesCache
+        if {[dict exists $imagesCache $im]} {
+            set im [dict get $imagesCache $im]
+        } else {
+            set impath $im
+            if {[string match "http*://*" $impath]} {
+                set im /tmp/[regsub -all {\W+} $impath "_"]
+                exec -ignorestderr curl -o$im $impath
+            }
+            if {[string match "*jpg" $im] ||
+                [string match "*jpeg" $im] ||
+                [string match "*png" $im]} {
+                # TODO: Support .png
+                set path [expr {[file pathtype $im] eq "relative" ?
+                                "$::env(HOME)/folk-images/$im" :
+                                $im}]
+                set im [image loadJpeg $path]
+                dict set imagesCache $impath $im
+            }
+        }
+        set im
+    }
+
     namespace export *
     namespace ensemble create
 }
@@ -116,9 +221,28 @@ When when /p/ has camera slice /slice/ /lambda/ with environment /e/ {
 
 # Display a camera slice
 When /someone/ wishes /p/ displays camera slice /slice/ & /p/ has region /r/ {
-  set origin [lindex $r 0 0]
+  set center [region centroid $r]
   # set scale [expr {$Display::WIDTH / $Camera::WIDTH}]
   # Use 1x scale instead of $scale so the projected tag doesn't redetect.
   # TODO: Mask the tag out?
-  Wish display runs [list Display::image {*}$origin $slice 1]
+    Wish display runs [list Display::image {*}$center $slice 0 1]
+}
+
+When /someone/ wishes /p/ displays image /im/ {
+    set im [image load $im]
+    When $p has region /r/ {
+        # Compute a scale for im that will fit in the region width/height
+        # Draw im with scale and rotation
+        set center [region centroid $r]
+        # set width [region width $r]
+        # set height [region height $r]
+        # set scale [expr {min($width / [image width $im],
+        #                      $height / [image height $im])}]
+        # Wish $p is labelled $im
+        Wish display runs [list Display::image {*}$center $im [region angle $r] 1]
+    }
+    # On unmatch {
+    #     # HACK: Leaves time for the display to finish trying to display this.
+    #     after 5000 [list image freeJpeg $im]
+    # }
 }
diff --git a/virtual-programs/mask-tags.folk b/virtual-programs/mask-tags.folk
new file mode 100644
index 00000000..4f0ae4b2
--- /dev/null
+++ b/virtual-programs/mask-tags.folk
@@ -0,0 +1,16 @@
+When tag /something/ has corners /corners/ {
+    set tagCorners [lmap p $corners {::cameraToProjector $p}]
+
+    set vecBottom [sub [lindex $tagCorners 1] [lindex $tagCorners 0]]
+    set vecRight [sub [lindex $tagCorners 2] [lindex $tagCorners 1]]
+
+    set offsets {{-0.5 -0.5} {0.5 -0.5} {0.5 0.5} {-0.5 0.5}}
+    set scales [matmul $offsets [list $vecBottom $vecRight]]
+    set corners [add $tagCorners $scales]
+
+    set p0 [lindex $corners 0]
+    set p1 [lindex $corners 1]
+    set p2 [lindex $corners 2]
+    set p3 [lindex $corners 3]
+    Display::drawOnTop Display::fillQuad $p0 $p1 $p2 $p3 black
+}
\ No newline at end of file
diff --git a/virtual-programs/points-at.folk b/virtual-programs/points-at.folk
index 1472b379..a037f98f 100644
--- a/virtual-programs/points-at.folk
+++ b/virtual-programs/points-at.folk
@@ -19,7 +19,7 @@ When /someone/ wishes /rect/ points /direction/ with length /l/ & /rect/ has reg
         set whiskerRegion [region scale $region height 0.01px width $scale]
         set whiskerRegion [region move $whiskerRegion left \
                                [vec2 distance [region right $whiskerRegion] [region left $region]]px]
-        set color red
+        set color gold
     } elseif {$direction eq "right"} {
         set whiskerRegion [region scale $region height 0.01px width $scale]
         set whiskerRegion [region move $whiskerRegion right \
diff --git a/virtual-programs/print.folk b/virtual-programs/print.folk
index badd191f..44a7d433 100644
--- a/virtual-programs/print.folk
+++ b/virtual-programs/print.folk
@@ -163,6 +163,10 @@ proc nextId {} {
         set id 0
     }
 
+    while {[file exists "$::env(HOME)/folk-printed-programs/$id.folk"]} {
+        incr id
+    }
+
     set fp [open "$::env(HOME)/folk-printed-programs/next-id.txt" w]
     puts $fp [expr {$id + 1}]
     close $fp
diff --git a/virtual-programs/regions.folk b/virtual-programs/regions.folk
index 5de19b98..945fcd20 100644
--- a/virtual-programs/regions.folk
+++ b/virtual-programs/regions.folk
@@ -1,3 +1,8 @@
 When when the distance between /p1/ and /p2/ is /distanceVar/ /body/ with environment /e/ & /p1/ has region /r1/ & /p2/ has region /r2/ {
     Claim the distance between $p1 and $p2 is [region distance $r1 $r2]
 }
+
+When /someone/ wishes region /r/ is /verbed/ /x/ {
+  Claim $r has region $r
+  Wish $r is $verbed $x
+}
diff --git a/virtual-programs/tags-and-calibration.folk b/virtual-programs/tags-and-calibration.folk
index afb4aef4..b219b541 100644
--- a/virtual-programs/tags-and-calibration.folk
+++ b/virtual-programs/tags-and-calibration.folk
@@ -119,7 +119,8 @@ When (non-capturing) tag /tag/ has center /c/ size /size/ {
 }
 
 When (non-capturing) tag /tag/ is a tag {
-     puts "Added tag $tag"
+    puts "Added tag $tag"
+    On unmatch { puts "Removed tag $tag" }
 
     set tempPath "$::env(HOME)/folk-printed-programs/$tag.folk.temp"
 
diff --git a/virtual-programs/terminal.folk b/virtual-programs/terminal.folk
new file mode 100644
index 00000000..3fb335b5
--- /dev/null
+++ b/virtual-programs/terminal.folk
@@ -0,0 +1,86 @@
+# Terminal
+#
+# Spawn terminals with any command (default "bash"):
+#   Wish $this is a terminal
+#   Wish $this is a terminal spawning "any command"
+#
+# Send keyboard events to the terminal:
+#   Claim $thing has keyboard input
+#
+# Optionally, draw the terminal on an arbitrary region:
+#   Claim $thing has terminal region $region
+#
+#
+# Example program: Tie it all together with a simple vim editor...
+#
+#   When $this points up at /target/ & /target/ has program /anything/ {
+#     Wish $this is a terminal spawning "vim ~/folk-printed-programs/$target.folk"
+#     When $this has region /r/ {
+#       Claim $this has terminal region [region move $r right 350px]
+#     }
+#     Claim $this has keyboard input
+#   }
+#
+#
+# Note: Terminals are killed after ::termExpireMs of being unmatched.
+#
+
+source lib/terminal.tcl
+
+set ::termExpireMs [expr {10*60*1000}] ;# 10 minutes
+set ::termInstances [dict create]
+set ::termTimeouts [dict create]
+
+proc ::matchTerminal {id cmd} {
+  set termKey "$id $cmd"
+  if {$termKey ni $::termInstances} {
+    dict set ::termInstances $termKey [Terminal::create 12 43 $cmd]
+  }
+  if {$termKey in $::termTimeouts} {
+    after cancel [dict get $::termTimeouts $termKey]
+    dict unset ::termTimeouts $termKey
+  }
+  dict get $::termInstances $termKey
+}
+
+proc ::unmatchTerminal {id cmd} {
+  set termKey "$id $cmd"
+  dict set ::termTimeouts $termKey [
+    after $::termExpireMs "::destroyTerminal [list $termKey]"
+  ]
+}
+
+proc ::destroyTerminal {termKey} {
+  Terminal::destroy [dict get $::termInstances $termKey]
+  dict unset ::termInstances $termKey
+  dict unset ::termTimeouts $termKey
+}
+
+When /anyone/ wishes /thing/ is a terminal {
+  Wish $thing is a terminal spawning bash
+}
+
+When /thing/ has terminal region /r/ & /r/ has keyboard input {
+  Claim $thing has keyboard input
+}
+
+When /anyone/ wishes /thing/ is a terminal spawning /cmd/ {
+  set term [::matchTerminal $thing $cmd]
+  On unmatch { ::unmatchTerminal $thing $cmd }
+
+  When $::thisProcess has step count /c/ {
+    set body {
+      Wish region $region is labelled [Terminal::read $term]
+    }
+    When $thing has terminal region /region/ $body
+    When /nobody/ claims $thing has terminal region /x/ & $thing has region /region/ $body
+  }
+
+  When /anyone/ claims $thing has keyboard input \
+    & /anyone/ claims key /key/ is /direction/ with modifiers /modifiers/ {
+    if {$direction != "up"} {
+      set ctrlPressed [expr {"ctrl" in $modifiers}]
+      Terminal::write $term $key $ctrlPressed
+    }
+  }
+}
diff --git a/virtual-programs/time.folk b/virtual-programs/time.folk
new file mode 100644
index 00000000..1dff734d
--- /dev/null
+++ b/virtual-programs/time.folk
@@ -0,0 +1,3 @@
+When $::thisProcess has step count /t/ {
+    Claim the clock time is [/ [clock milliseconds] 1000.0]
+}
diff --git a/web.tcl b/web.tcl
index 37081ba2..fd6ec2db 100644
--- a/web.tcl
+++ b/web.tcl
@@ -14,10 +14,10 @@ proc readFile {filename contentTypeVar} {
     set response [read $fd]; close $fd; return $response
 }
 
-proc readPdf {dotCmd contentTypeVar} {
+proc getDotAsPdf {dot contentTypeVar} {
     upvar $contentTypeVar contentType
     set contentType "application/pdf"
-    set fd [open |[list dot -Tpdf <<$dotCmd] r]
+    set fd [open |[list dot -Tpdf <<$dot] r]
     fconfigure $fd -encoding binary -translation binary
     set response [read $fd]; close $fd; return $response
 }
@@ -50,6 +50,7 @@ proc handlePage {path contentTypeVar} {
                 </head>
                 <nav>
                 <a href="/new"><button>New program</button></a>
+                <a href="/programs">Running programs</a>
                 <a href="/timings">Timings</a>
                 <a href="/statementClauseToId.pdf">statementClauseToId graph</a>
                 <a href="/statements.pdf">statements graph</a>
@@ -59,6 +60,23 @@ proc handlePage {path contentTypeVar} {
                 </html>
             }
         }
+        "/programs" {
+            set programs [Statements::findMatches [list /someone/ claims /programName/ has program /program/]]
+            subst {
+                <html>
+                <head>
+                <link rel="stylesheet" href="/style.css">
+                <title>Running programs</title>
+                </head>
+                <body>
+                [join [lmap p $programs { dict with p {subst {
+                    <h2>$programName</h2>
+                    <pre><code>[htmlEscape [lindex $program 1]]</code></pre>
+                }} }] "\n"]
+                </body>
+                </html>
+            }
+        }
         "/timings" {
             set totalTimes [list]
             dict for {body totalTime} $Evaluator::totalTimesMap {
@@ -68,9 +86,11 @@ proc handlePage {path contentTypeVar} {
             }
             set totalTimes [lsort -integer -stride 2 -index 1 $totalTimes]
 
+            set totalFrameTime 0
             set l [list]
             foreach {body totalTime} $totalTimes {
                 set runs [dict get $Evaluator::runsMap $body]
+                set totalFrameTime [expr {$totalFrameTime + $totalTime/$::stepCount}]
                 lappend l [subst {
                     <li>
                     <pre>[htmlEscape $body]</pre> ($runs runs): [dict get $Evaluator::totalTimesMap $body]: $totalTime microseconds total ([expr {$totalTime/$::stepCount}] us per frame), $runs runs ([expr {$totalTime/$runs}] us per run; [expr {$runs/$::stepCount}] runs per frame)
@@ -89,7 +109,7 @@ proc handlePage {path contentTypeVar} {
                 <a href="/statementClauseToId.pdf">statementClauseToId graph</a>
                 <a href="/statements.pdf">statements graph</a>
                 </nav>
-                <h1>Timings</h1>
+                <h1>Timings (sum per-frame time $totalFrameTime us)</h1>
                 <ul>[join $l "\n"]</ul>
                 </html>
             }
@@ -103,13 +123,10 @@ proc handlePage {path contentTypeVar} {
             readFile "assets/style.css" contentType
         }
         "/statementClauseToId.pdf" {
-            readPdf [trie dot $Statements::statementClauseToId] contentType
+            getDotAsPdf [trie dot [Statements::statementClauseToIdTrie]] contentType
         }
         "/statements.pdf" {
-            readPdf [Statements::dot] contentType
-        }
-        "/statementPatternToReactions.pdf" {
-            readPdf [trie dot $Evaluator::statementPatternToReactions] contentType
+            getDotAsPdf [Statements::dot] contentType
         }
         default {
             subst {