Rework keyboard and implement global terminal

8 files changed, 1641 insertions, 146 deletions

diff --git a/.gitignore b/.gitignore
index 281d7b1e..36c1aab4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,3 +4,4 @@ statements.dot
 trie.pdf
 trie.dot
 virtual-programs/program-positions.tcl
+capture*.jpg
diff --git a/pi/KeyCodes.tcl b/pi/KeyCodes.tcl
index 4ca8d4ad..880a2e65 100644
--- a/pi/KeyCodes.tcl
+++ b/pi/KeyCodes.tcl
@@ -1,129 +1,147 @@
 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
+
+# In the future, probably could make use of KDB's libkeymap to support more than basic ANSI
+# See: http://kbd-project.org/
+
+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..3ac0d803 100644
--- a/pi/Keyboard.tcl
+++ b/pi/Keyboard.tcl
@@ -33,7 +33,8 @@ namespace eval Keyboard {
         fconfigure $kb -translation binary
     }
 
-    proc getChar {} {
+    # Returns a tuple of [keycode up/down/repeated]
+    proc getKeyEvent {} {
         # 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 +43,23 @@ 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
+            # TODO: is this CPU dependant? Originally was 16 bytes with 32-bit longs
+            # Could check [getconf LONG_BIT] for 32 or 64...
+            binary scan [read $Keyboard::kb 24] wwsss tvSec tvUsec type code value
+            if {$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]
-}
+# 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 a3b73281..80d6a5b1 100644
--- a/pi/pi.tcl
+++ b/pi/pi.tcl
@@ -5,18 +5,44 @@ thread::errorproc errorproc
 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]]
+            if {[llength $heldModifiers] == 0} {set heldModifiers " "}
 
             thread::send -async "%s" [subst {
-                Retract keyboard claims the keyboard character log is /something/
-                Assert keyboard claims the keyboard character log is "$chs"
+                # TODO: can't use open-square-bracket or backslash keys
+                Retract keyboard claims key /k/ is /t/ with modifiers /m/
+                Assert keyboard claims key "$key" is $keyState with modifiers "$heldModifiers"
             }]
         }
     } [thread::id]]]
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/terminal.folk b/virtual-programs/terminal.folk
new file mode 100644
index 00000000..df333d28
--- /dev/null
+++ b/virtual-programs/terminal.folk
@@ -0,0 +1,170 @@
+# Terminal
+#
+# Claim $this is a terminal
+#
+
+set cc [c create]
+$cc cflags -I./vendor/libtmt ./vendor/libtmt/tmt.c
+
+# TODO: find the right libutil.so for the system
+c loadlib /lib/aarch64-linux-gnu/libutil.so
+$cc cflags -lutil
+
+$cc include <sys/types.h>
+$cc include <stdio.h>
+$cc include <stdlib.h>
+$cc include <unistd.h>
+$cc include <pty.h>
+$cc include <fcntl.h>
+$cc include <string.h>
+$cc include <sys/time.h> ;# For gettimeofday()
+
+$cc code {
+  #include "tmt.h"
+
+  #define SHELL "/bin/bash"
+
+  #define ROWS 12
+  #define COLS 43
+  char screen[ROWS][COLS + 1];
+  int curs_r = 0;
+  int curs_c = 0;
+
+
+  #define PTYBUF 4096
+  char iobuf[PTYBUF];
+
+  TMT *vt;
+  int pty_fd;
+
+  void callback(tmt_msg_t m, TMT *vt, const void *a, void *p) {
+      const TMTSCREEN *s = tmt_screen(vt);
+
+      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++){
+                  screen[r][c] = s->lines[r]->chars[c].c;
+                }
+            }
+        }
+        tmt_clean(vt);
+      }
+  }
+
+  void initScreen() {
+    for (int r = 0; r < ROWS - 1; r++) {
+      screen[r][COLS] = '\n';
+    }
+    screen[ROWS - 1][COLS] = '\0';
+  }
+
+  void updateCursor() {
+    // Restore char under old cursor
+    const TMTSCREEN *s = tmt_screen(vt);
+    screen[curs_r][curs_c] = s->lines[curs_r]->chars[curs_c].c;
+
+    // Update new cursor
+    const TMTPOINT *c = tmt_cursor(vt);
+    curs_r = c->r;
+    curs_c = c->c;
+
+    // Replace char with cursor every other second
+    struct timeval tv;
+    gettimeofday(&tv, NULL);
+    if (tv.tv_sec % 2 == 0) {
+      screen[curs_r][curs_c] = 0xDB; // block char: █
+    }
+  }
+}
+
+$cc proc termInit {} bool {
+  if (vt != NULL) {
+    return false;
+  }
+
+  initScreen();
+  vt = tmt_open(ROWS, COLS, callback, NULL, NULL);
+
+  struct winsize ws = {.ws_row = ROWS, .ws_col = COLS};
+  pid_t pid = forkpty(&pty_fd, NULL, NULL, &ws);
+  if (pid < 0){
+    return false;
+  } else if (pid == 0){
+    setenv("TERM", "ansi", 1);
+    execl(SHELL, SHELL, NULL);
+    return true;
+  }
+
+  fcntl(pty_fd, F_SETFL, O_NONBLOCK);
+  return true;
+}
+
+$cc proc termRead {} char* {
+  ssize_t r = read(pty_fd, iobuf, PTYBUF);
+  if (r > 0) {
+    tmt_write(vt, iobuf, r);
+  }
+
+  updateCursor();
+  return (char*)screen;
+}
+
+$cc proc termWrite {char* key} void {
+  write(pty_fd, key, strlen(key));
+}
+
+$cc compile
+
+# Folk stuff...
+
+# From `man console_codes`
+set keymap [dict create \
+  ENTER     "\x0d" \
+  TAB       "\x09" \
+  BACKSPACE "\x08" \
+  DELETE    "\x7f" \
+  ESC       "\x1b" \
+  UP        "\x1b\[A" \
+  DOWN      "\x1b\[B" \
+  RIGHT     "\x1b\[C" \
+  LEFT      "\x1b\[D" \
+]
+
+proc remap {key modifiers} {
+  upvar keymap keymap
+  if {[string length $key] == 1} {
+    # Convert ctrl-A through ctrl-Z and others to terminal control characters
+    if {"ctrl" in $modifiers} {
+      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 $key]
+  }
+  return ""
+}
+
+When /anyone/ claims /thing/ is a terminal {
+  termInit
+
+  When /anyone/ claims key /key/ is /direction/ with modifiers /modifiers/ {
+    if {$direction != "up"} {
+      set key [remap $key $modifiers]
+      if {[string length $key] > 0} {
+        termWrite $key
+      }
+    }
+  }
+
+  When $thing has region /r/ & /node/ has step count /c/ {
+    set display [region move $r up 180px]
+    Wish region $display is labelled [termRead]
+  }
+}