Value -> Value/Event/IO-Stream

Close 12

4 files changed, 93 insertions, 117 deletions

diff --git a/core/base/init.moon b/core/base/init.moon
index bb35140..8e376fc 100644
--- a/core/base/init.moon
+++ b/core/base/init.moon
@@ -4,28 +4,27 @@
 -- This module exports the following classes that extension modules may need:
 --
 -- @module base
--- @see IO
 -- @see Op
 -- @see Action
 -- @see FnDef
 -- @see Input
 -- @see match
--- @see Value
+-- @see ValueStream
+-- @see EventStream
+-- @see IOStream
 -- @see Result
 -- @see Error
 
-import IO from require 'core.base.io'
 import Op from require 'core.base.op'
 import Action from require 'core.base.action'
 import FnDef from require 'core.base.fndef'
 import Input from require 'core.base.input'
 import match from require 'core.base.match'
-import Value from require 'core.value'
+import ValueStream, EventStream, IOStream from require 'core.stream'
 import Result from require 'core.result'
 import Error from require 'core.error'
 
 {
-  :IO
   :Op
   :Action
   :FnDef
@@ -33,5 +32,6 @@ import Error from require 'core.error'
   :match
 
   -- redundant exports, to keep anything an extension might need in one import
-  :Value, :Result, :Error
+  :ValueStream, :EventStream, :IOStream
+  :Result, :Error
 }
diff --git a/core/base/input.moon b/core/base/input.moon
index c89337f..6922a4f 100644
--- a/core/base/input.moon
+++ b/core/base/input.moon
@@ -2,10 +2,29 @@
 -- Update scheduling policy for `Op` arguments.
 --
 -- @classmod Input
-import Value from require 'core.value'
+import ValueStream, EventStream, IOStream from require 'core.stream'
 import Result from require 'core.result'
 
-local ColdInput, ValueInput, EventInput, IOInput
+inherits = (klass, frm) ->
+  assert klass, "cant find the ancestor of nil"
+  return true if klass == frm
+  while klass.__parent
+    return true if klass.__parent == frm
+    klass = klass.__parent
+  false
+
+match_parent = (inst, map) ->
+  klass = assert inst and inst.__class, "not an instance"
+  if key = map[klass]
+    return key
+
+  while klass.__parent
+    if key = map[klass.__parent]
+      return key
+
+    klass = klass.__parent
+
+local ColdInput, ValueInput, IOInput, mapping
 
 class Input
 --- Input interface.
@@ -15,20 +34,10 @@ class Input
 
   --- create a new Input.
   --
-  -- `value` is either a `Value` or a `Result` instance and should be
-  -- unwrapped and assigned to `stream`.
-  --
   -- @classmethod
-  -- @tparam Value|Result value
-  new: (value) =>
-    assert value, "nil passed to Input: #{value}"
-    @stream = switch value.__class
-      when Result
-        assert value.value, "Input from result without value!"
-      when Value
-        value
-      else
-        error "Input from unknown value: #{value}"
+  -- @tparam Stream stream
+  new: (@stream) =>
+    assert @stream, "nil passed to Input: #{value}"
 
   --- copy state from old instance (optional).
   --
@@ -44,7 +53,7 @@ class Input
   --
   -- must return a boolean indicating whether `Op`s that refer to this instance
   -- should be notified (via `Op:tick`). If not overwritten, delegates to
-  -- `stream`:@{Value:dirty|dirty}.
+  -- `stream`:@{ValueStream:dirty|dirty}.
   --
   -- @treturn bool whether processing is necessary
   dirty: => @stream\dirty!
@@ -65,7 +74,7 @@ class Input
 
   --- the current value
   --
-  -- @tfield Value stream
+  -- @tfield ValueStream stream
 
 --- members
 -- @section members
@@ -86,33 +95,29 @@ class Input
   -- Never marked dirty. Use this for input streams that are only read when
   -- another `Input` is dirty.
   --
-  -- @tparam Value|Result value
-  @cold: (value) -> ColdInput value
+  -- @tparam Stream|Result value
+  @cold: (value) ->
+    if value.__class == Result
+      value = assert value.value, "Input from result without value!"
+    ColdInput value
 
-  --- Create a `value` `Input`.
+  --- Create a `hot` `Input`.
   --
-  -- Marked dirty for the eval-tick if old and new `Value` differ. This is the
-  -- most common `Input` strategy. Should be used whenever a
-  -- value denotes state.
+  -- Behaviour depends on what kind of `Stream` `value` is:
   --
-  -- @tparam Value|Result value
-  @value: (value) -> ValueInput value
-
-  --- Create an `event` `Input`.
+  -- - `ValueStream`: Marked dirty for the eval-tick if old and new `ValueStream` differ.
+  -- - `EventStream` and `IOStream`: Marked dirty only if the current `EventStream` is dirty.
   --
-  -- Only marked dirty if the `Value` itself is dirty. Should be used whenever
-  -- an `Input` denotes a momentary event or impulse.
+  -- This is the most common `Input` strategy.
   --
-  -- @tparam Value|Result value
-  @event: (value) -> EventInput value
+  -- @tparam Stream|Result value
+  @hot: (value) ->
+    if value.__class == Result
+      value = assert value.value, "Input from result without value!"
 
-  --- Create an `IO` `Input`.
-  --
-  -- Marked dirty only when an `IO` is dirty. Must be used only for `Value`s
-  -- which @{Value:unwrap|unwrap} to `IO` instances.
-  --
-  -- @tparam Value|Result value
-  @io: (value) -> IOInput value
+    InputType = match_parent value, mapping
+    assert InputType, "Input from unknown value: #{value}"
+    InputType value
 
 class ColdInput extends Input
   dirty: => false
@@ -124,11 +129,14 @@ class ValueInput extends Input
     return @dirty_setup if @dirty_setup != nil
     @stream\dirty!
 
-class EventInput extends Input
-
 class IOInput extends Input
-  impure: true
-  dirty: => @stream\unwrap!\dirty!
+  io: true
+
+mapping = {
+  [ValueStream]: ValueInput
+  [EventStream]: Input
+  [IOStream]: IOInput
+}
 
 {
   :Input
diff --git a/core/base/io.moon b/core/base/io.moon
deleted file mode 100644
index cbb5823..0000000
--- a/core/base/io.moon
+++ /dev/null
@@ -1,40 +0,0 @@
-----
--- Incoming side-effect adapter, creating events for the dataflow graph.
---
--- Polled by the main event loop to kick of events that cause the the dataflow
--- graph to ripple results.
---
--- @classmod IO
-
-class IO
---- IO interface.
---
--- methods that have to be implemented by `IO` implementations.
--- @section interface
-
-  --- construct a new instance.
-  --
-  -- Must prepare the instance for `dirty` to be called.
-  -- @classmethod
-  new: =>
-
-  --- poll for changes.
-  --
-  -- Called every frame by the main event loop to update internal state.
-  tick: =>
-
-  --- check whether this adapter requires processing.
-  --
-  -- Must return a boolean indicating whether `Op`s that refer to this instance
-  -- via `Input.io` should be notified (via `Op:tick`). May be called multiple
-  -- times. May be called before `tick` on the first frame after construction.
-  --
-  -- @treturn bool whether processing is required
-  dirty: =>
-
-  __tostring: => "<IO #{@@__name}>"
-  __inherited: (cls) => cls.__base.__tostring = @__tostring
-
-{
-  :IO
-}
diff --git a/core/base/op.moon b/core/base/op.moon
index a8da100..4880afd 100644
--- a/core/base/op.moon
+++ b/core/base/op.moon
@@ -2,16 +2,16 @@
 -- Persistent expression Operator.
 --
 -- @classmod Op
-import Value from require 'core.value'
 
-ident = (tbl) ->
-  mt = getmetatable tbl
-  setmetatable tbl, nil
-
-  id = tostring tbl
-
-  setmetatable tbl, mt
-  id\sub #'table: 0x'
+deepcopy = (val) ->
+  switch type val
+    when 'number', 'string', 'boolean'
+      val
+    when 'table'
+      assert (not getmetatable {}), "state should only contain simple tables!"
+      {(deepcopy k), (deepcopy v) for k,v in pairs val}
+    else
+      error "state cannot contain values of type '#{type val}'"
 
 class Op
 --- members
@@ -33,23 +33,30 @@ class Op
   -- Used to wrap insulate eval-cycles from each other. The copy does not have
   -- `inputs` set, since it is expected that this is (re)set in `setup`.
   --
-  -- @treturn Value
+  -- @treturn Op
   fork: =>
-    with setmetatable {}, getmetatable @
-      .state = {k,v for k,v in pairs @state} if @state
-      .out = @out\fork! if @out
+    out = if @out then @out\fork
+    state = if @state then deepcopy state
+    @@ out, state
+
+  --- internal state of this Op.
+  --
+  -- This may be any simple Lua value, including Lua tables, as long as it has
+  -- no metatables, multiple references/loops, userdata etc.
+  --
+  -- @tfield table state
 
-  --- `Value` instance representing this Op's computed output value.
+  --- `Stream` instance representing this Op's computed output value.
   --
-  -- Must be set to a `Value` instance once `setup` finishes. Must not change
-  -- type, be removed or replaced outside of `new` and `setup`. Should have a
-  -- value assigned via `set` or the `Value` constructor once `tick` is
-  -- called the first time. If `out`'s value is not initialized in `new`
-  -- or `setup`, the implementation must make sure `tick``(true)` is called at
-  -- least on the first eval-cycle the Op goes through, e.g. by using an
-  -- `Input.value`.
+  -- Must be set to a `Stream` instance once `setup` finishes. Must not change
+  -- type, be removed or replaced outside of `new` and `setup`. If it is a
+  -- `ValueStream`, it should have a value assigned via `set` or the
+  -- constructor once `tick` is called the first time. If `out`'s value is not
+  -- initialized in `new` or `setup`, the implementation must make sure
+  -- `tick``(true)` is called at -- least on the first eval-cycle the Op goes
+  -- through, e.g. by using an `Input.value`.
   --
-  -- @tfield Value out
+  -- @tfield Stream out
 
   --- table containing `Input`s to this Op.
   --
@@ -66,10 +73,14 @@ class Op
 
   --- construct a new instance.
   --
-  -- The super-constructor can be used to construct a `Value` instance in `out`.
+  -- The optional parameters `out` and `state` are used by `fork` to duplicate
+  -- an instance. If the constructor is overriden, these parameters must be
+  -- forwarded to the superconstructor unchanged.
   --
   -- @function new
   -- @classmethod
+  -- @tparam ?Stream out `out`
+  -- @tparam ?table state `state`
 
   --- parse arguments and patch self.
   --
@@ -109,12 +120,9 @@ class Op
   -- type is not known at this time.
   --
   -- @classmethod
-  -- @tparam[opt] string type the type-name for `out`
-  -- @tparam[optchain] any init the initial value for `out`
-  new: (type, init) =>
-    @state = {}
-    if type
-      @out = Value type, init
+  -- @tparam ?Stream out `out`
+  -- @tparam ?table state `state`
+  new: (@out, @state) =>
 
   do_setup = (old, cur) ->
     for k, cur_val in pairs cur