IO system

5 files changed, 48 insertions, 10 deletions

diff --git a/core/base.moon b/core/base.moon
index 0a88cc1..6af4913 100644
--- a/core/base.moon
+++ b/core/base.moon
@@ -5,6 +5,7 @@ unpack or= table.unpack
 
 class Input
   new: (value) =>
+    assert value, "nil passed to Input: #{value}"
     @stream = switch value.__class
       when Result
         assert value.value, "Input from result without value!"
@@ -19,8 +20,12 @@ class Input
   dirty: => @stream\dirty!
   unwrap: => @stream\unwrap!
   type: => @stream.type
+
   __call: => @stream\unwrap!
-  __inherited: (cls) => cls.__base.__call = @__call
+  __tostring: => "#{@@__name}:#{@stream}"
+  __inherited: (cls) =>
+    cls.__base.__call = @__call
+    cls.__base.__tostring = @__tostring
 
 -- ValueInput scheduling policy
 --
@@ -35,6 +40,19 @@ class ValueInput extends Input
 -- only marked dirty if the input stream itself is dirty
 class EventInput extends Input
 
+-- IOInput scheduling policy
+--
+-- lifts streams of IO objects to events
+class IOInput extends Input
+  dirty: => @stream\unwrap!\dirty!
+
+class IO
+  -- called in the main event loop
+  tick: =>
+
+  -- whether a tree update is necessary
+  dirty: =>
+
 -- a persistent expression Operator
 --
 -- accepts Const or Stream inputs and produces a Stream output
@@ -61,7 +79,7 @@ class Op
         if cur_plain and old_plain
           -- both are tables, recurse
           do_merge old_val, cur_val
-        elseif cur_plain == old_plain
+        elseif not (cur_plain or old_plain)
           -- both are streams (or nil), merge them
           cur_val\merge old_val
 
@@ -191,8 +209,9 @@ class FnDef
     "(fn (#{table.concat [p\stringify! for p in *@params], ' '}) ...)"
 
 {
-  :ValueInput, :EventInput
+  :ValueInput, :EventInput, :IOInput
   :Dispatcher
+  :IO
   :Op
   :Action
   :FnDef
diff --git a/core/init.moon b/core/init.moon
index a309722..6b5bdd0 100644
--- a/core/init.moon
+++ b/core/init.moon
@@ -1,6 +1,8 @@
 L or= setmetatable {}, __index: => ->
 
-import Op, Action, FnDef from require 'core.base'
+import Op, IO, Action, FnDef, EventInput, ValueInput, IOInput
+  from require 'core.base'
+import match from require 'core.pattern'
 
 import Value, Result, load_ from require 'core.value'
 import Scope from require 'core.scope'
@@ -17,7 +19,9 @@ globals = Scope.from_table require 'core.builtin'
 {
   :Value, :Result
   :Cell, :RootCell
-  :Op, :Action, :FnDef
+
+  :Op, :IO, :Action, :FnDef
+  :EventInput, :ValueInput, :IOInput, :match
   :Scope
 
   :Registry, :Tag
diff --git a/core/pattern.moon b/core/pattern.moon
index 64b53b8..13497af 100644
--- a/core/pattern.moon
+++ b/core/pattern.moon
@@ -35,13 +35,20 @@ class Pattern
       matched = while @matches results[1]
         table.remove results, 1
 
-      assert @opt or #matched > 0, "expected at least one argument for spread!"
+      assert @opt or #matched > 0, "expected at least one argument for spread"
       matched
     else
       matches = @matches results[1]
-      assert @opt or matches, "couldn't match argument #{results[1]} as type #{@type}!"
+      assert @opt or matches, "couldn't match argument #{results[1]} as #{@}"
       if matches then table.remove results, 1
 
+  __tostring: =>
+    str = @type
+    str = '*' .. str if @splat
+    str = '=' .. str if @const
+    str = str .. '?' if @opt
+    str
+
 match = (pattern, results) ->
   patterns = while pattern
     pat, rest = pattern\match '^([^ ]+) (.*)$'
diff --git a/core/registry.moon b/core/registry.moon
index 2a83f7e..ac1943a 100644
--- a/core/registry.moon
+++ b/core/registry.moon
@@ -3,6 +3,7 @@ import Result, Value from require 'core.value'
 class Registry
   new: () =>
     @map = {}
+    @io = {}
 
     @tick = 0
     @kr = Result value: Value.bool true
@@ -22,6 +23,10 @@ class Registry
 
   active: -> assert Registry.active_registry, "no active Registry!"
 
+-- IO
+  add_io: (io) => @io[io] = true
+  remove_io: (io) => @io[io] = nil
+
 -- public methods
 
   wrap_eval: (fn) => (...) ->
@@ -50,6 +55,9 @@ class Registry
     @tick += 1
     @kr.value\set true
 
+    for io in pairs @io
+      io\tick!
+
     with fn ...
       @release!
 
diff --git a/core/value.moon b/core/value.moon
index 0d44320..0e72486 100644
--- a/core/value.moon
+++ b/core/value.moon
@@ -36,8 +36,8 @@ class Result
 
     if @op
       for input in @op\all_inputs!
-        continue if is_child[input]
-        @side_inputs[input] = true
+        continue if is_child[input.stream]
+        @side_inputs[input.stream] = true
 
   is_const: => not next @side_inputs
 
@@ -97,7 +97,7 @@ class Value
   --                             * scope, opdef, fndef, builtin
   -- @value     - Lua value - access through :unwrap()
   new: (@type, @value, @raw) =>
-    @updated = 0
+    @updated = nil
 
   dirty: => @updated == Registry.active!.tick