merge Const and Stream into Value; Dataflow logic

lib not fully ported / functonial

9 files changed, 206 insertions, 135 deletions

diff --git a/core/base.moon b/core/base.moon
index 1b1be5d..60ee460 100644
--- a/core/base.moon
+++ b/core/base.moon
@@ -1,21 +1,47 @@
 -- base definitions for extensions
+import Value from require 'core.value'
+
+unpack or= table.unpack
 
 -- a persistent expression Operator
 --
 -- accepts Const or Stream inputs and produces a Stream output
 class Op
-  update: (dt) =>
+  new: (type, init) =>
+    @impulses = {}
+
+    if type
+      @out = Value type, init
+
+  -- (re)-initialize this Op with the given inputs
+  -- after this method finishes, :tick(true) is called once, after which
+  -- @impulses and @out have to be set and may not change until :setup()
+  -- is called again.
+  setup: (@inputs) =>
 
-  -- set @out to a Value (Const or Stream)
-  setup: (...) =>
+  -- called once per frame if any inputs or impulses are dirty, and once
+  -- immediately after :setup(). 'first' will be true in the latter case.
+  -- Should update @out.
+  tick: (first) =>
 
+  -- called once when the Op is destroyed
   destroy: =>
 
+-- utilities
+  unwrap_inputs: =>
+    unpack [input! for input in *@inputs]
+
+  assert_types: (...) =>
+    num = select '#', ...
+    assert #@inputs >= num, "argument count mismatch"
+    for i = 1, num
+      expect = select i, ...
+      assert @inputs[i].type == expect, "expected argument #{i} of #{@} to be of type #{expect} but found #{@inputs[i]}"
+
 -- static
   __tostring: => "<op: #{@@__name}>"
   __inherited: (cls) => cls.__base.__tostring = @__tostring
 
-
 -- a builtin / special form / cell-evaluation strategy
 --
 -- responsible for quoting/evaluating subexpressions,
@@ -51,7 +77,7 @@ class Action
 -- static
   -- find & patch the action for the expression with Tag 'tag' if it exists,
   -- and is compatible with the new Cell contents, otherwise instantiate it.
-  -- register the action with the tag, evaluate it and return the ResultNode
+  -- register the action with the tag, evaluate it and return the Result
   @eval_cell: (scope, tag, head, tail) =>
     last = tag\last!
     compatible = last and
@@ -93,6 +119,7 @@ class FnDef
     "(fn (#{table.concat [p\stringify! for p in *@params], ' '}) ...)"
 
 {
+  :Dispatcher
   :Op
   :Action
   :FnDef
diff --git a/core/builtin.moon b/core/builtin.moon
index 71beac3..6abcbd9 100644
--- a/core/builtin.moon
+++ b/core/builtin.moon
@@ -1,6 +1,6 @@
 -- builtin special forms
 import Action, FnDef from require 'core.base'
-import ResultNode, Value, Const from require 'core.value'
+import Result, Value from require 'core.value'
 import Cell from require 'core.cell'
 import Scope from require 'core.scope'
 
@@ -13,7 +13,7 @@ prints the docstring for sym in the console"
     assert #tail == 1, "'doc' takes exactly one parameter"
 
     def = L\push tail[1]\eval, scope
-    with ResultNode children: { def }
+    with Result children: { def }
       def = def.value\const!\unwrap!
       L\print "(doc #{tail[1]\stringify!}):\n#{def.doc}\n"
 
@@ -35,9 +35,9 @@ updates all val-exprs."
         name = (name\quote scope)\unwrap 'sym'
 
         with val_expr\eval scope
-          scope\set name, .value
+          scope\set name, \make_ref!
 
-    ResultNode :children
+    Result :children
 
 class use extends Action
   @doc: "(use scope1 [scope2]...) - merge scopes into parent scope
@@ -49,10 +49,10 @@ all scopes have to be eval-time constants."
     L\trace "evaling #{@}"
     for child in *tail
       result = L\push child\eval, scope
-      value = result\value_only!\const!
+      value = result\const!
       scope\use value\unwrap 'scope', "'use' only works on scopes"
 
-    ResultNode!
+    Result!
 
 class require_ extends Action
   @doc: "(require name-str) - require a module
@@ -65,10 +65,10 @@ name-str has to be an eval-time constant."
     assert #tail == 1, "'require' takes exactly one parameter"
 
     result = L\push tail[1]\eval, scope
-    name = result\value_only!\const!
+    name = result\const!
 
     L\trace @, "loading module #{name}"
-    ResultNode value: Value.wrap require "lib.#{name\unwrap 'str'}"
+    Result value: Value.wrap require "lib.#{name\unwrap 'str'}"
 
 class import_ extends Action
   @doc: "(import sym1 [sym2]...) - require and define modules
@@ -81,9 +81,9 @@ requires modules sym1, sym2, ... and defines them as sym1, sym2, ... in the curr
 
     for child in *tail
       name = (child\quote scope)\unwrap 'sym'
-      scope\set name, Value.wrap require "lib.#{name}"
+      scope\set name, Result value: Value.wrap require "lib.#{name}"
 
-    ResultNode!
+    Result!
 
 class import_star extends Action
   @doc: "(import* sym1 [sym2]...) - require and use modules
@@ -99,7 +99,7 @@ requires modules sym1, sym2, ... and merges them into the current scope"
       name = (child\quote scope)\unwrap 'sym'
       scope\use (Value.wrap require "lib.#{name}")\unwrap 'scope'
 
-    ResultNode!
+    Result!
 
 class fn extends Action
   @doc: "(fn (p1 [p2]...) body-expr) - declare a (lambda) function
@@ -117,7 +117,7 @@ the symbols p1, p2, ... will resolve to the arguments passed to the function."
       param\quote scope
 
     body = body\quote scope
-    ResultNode value: Value.wrap FnDef param_symbols, body, scope
+    Result value: Value.wrap FnDef param_symbols, body, scope
 
 class defn extends Action
   @doc: "(defn name-sym (p1 [p2]...) body-expr) - define a function
@@ -138,8 +138,8 @@ declares a lambda (see (doc fn)) and defines it in the current scope"
     body = body\quote scope
     fn = FnDef param_symbols, body, scope
 
-    scope\set name, Value.wrap fn
-    ResultNode!
+    scope\set name, Result value: Value.wrap fn
+    Result!
 
 class do_expr extends Action
   @doc: "(do expr1 [expr2]...) - update multiple expressions
@@ -148,7 +148,7 @@ evaluates and continously updates expr1, expr2, ...
 the last expression's value is returned."
 
   eval: (scope, tail) =>
-    ResultNode children: [expr\eval scope for expr in *tail]
+    Result children: [expr\eval scope for expr in *tail]
 
 class if_ extends Action
   @doc: "(if bool then-expr [else-xpr]) - make an eval-time const choice
@@ -164,7 +164,7 @@ to then-expr, otherwise it is equivalent to else-xpr if given, or nil otherwise.
     { xif, xthen, xelse } = tail
 
     xif = L\push xif\eval, scope
-    xif = xif\value_only!\const!\unwrap!
+    xif = xif\const!\unwrap!
 
     if xif
       xthen\eval scope
@@ -189,8 +189,8 @@ class trace extends Action
   import: import_
   'import*': import_star
 
-  true: Const.bool true
-  false: Const.bool false
+  true: Value.bool true
+  false: Value.bool false
 
   :fn, :defn
   'do': do_expr
diff --git a/core/cell.moon b/core/cell.moon
index 642e1a6..0cb8e9f 100644
--- a/core/cell.moon
+++ b/core/cell.moon
@@ -1,5 +1,5 @@
 -- ALV Cell type
-import Const from require 'core.value'
+import Value from require 'core.value'
 import op_invoke, fn_invoke from require 'core.invoke'
 import Tag from require 'core.tag'
 
@@ -11,7 +11,8 @@ class Cell
   -- white:    optional sequence of whitespace segments ([0 .. #@children])
   new: (@tag=Tag.blank!, @children, @white) =>
     if not @white
-      @white = ['' for i=1,#@children+1]
+      @white = ['' for i=1,#@children]
+      @white[0] = ''
 
     assert #@white == #@children, "mismatched whitespace length"
 
@@ -22,8 +23,7 @@ class Cell
 
 -- AST interface
   eval: (scope) =>
-    head_result = @head!\eval scope
-    head = head_result.value\const!
+    head = (@head!\eval scope)\const!
     Action = switch head.type
       when 'opdef'
         -- scope\get 'op-invoke'
@@ -89,7 +89,7 @@ class Cell
 --
 -- evaluates with an implicit 'do' in the head
 class RootCell extends Cell
-  head: => Const.sym 'do'
+  head: => Value.sym 'do'
   tail: => @children
 
   stringify: =>
diff --git a/core/init.moon b/core/init.moon
index b885747..a309722 100644
--- a/core/init.moon
+++ b/core/init.moon
@@ -2,7 +2,7 @@ L or= setmetatable {}, __index: => ->
 
 import Op, Action, FnDef from require 'core.base'
 
-import Stream, Const, load_ from require 'core.value'
+import Value, Result, load_ from require 'core.value'
 import Scope from require 'core.scope'
 load_!
 
@@ -15,7 +15,7 @@ import cell, program from require 'core.parsing'
 globals = Scope.from_table require 'core.builtin'
 
 {
-  :Stream, :Const
+  :Value, :Result
   :Cell, :RootCell
   :Op, :Action, :FnDef
   :Scope
@@ -30,5 +30,5 @@ globals = Scope.from_table require 'core.builtin'
 
       ast = assert (cell\match str), "failed to parse: #{str}"
       result = ast\eval scope
-      result\value_only!
+      result\const!
 }
diff --git a/core/invoke.moon b/core/invoke.moon
index 5a6c420..a3932f8 100644
--- a/core/invoke.moon
+++ b/core/invoke.moon
@@ -1,4 +1,4 @@
-import ResultNode, Value from require 'core.value'
+import Result, Value from require 'core.value'
 import Action from require 'core.base'
 import Scope from require 'core.scope'
 
@@ -8,16 +8,17 @@ class op_invoke extends Action
 
     @op\destroy! if @op
 
-    def = head\const!\unwrap 'opdef', "cant op-invoke #{@head}"
+    def = head\unwrap 'opdef', "cant op-invoke #{@head}"
     @head, @op = head, def!
 
     true
     
   eval: (scope, tail) =>
     children = L\push -> [L\push expr\eval, scope for expr in *tail]
-    value = @op\setup unpack [child.value for child in *children]
+    @op\setup [child.value for child in *children]
+    @op\tick true
 
-    ResultNode :children, :value, op: @op
+    Result :children, value: @op.out, op: @op
 
 class fn_invoke extends Action
   -- @TODO:
@@ -32,7 +33,7 @@ class fn_invoke extends Action
     true
 
   eval: (outer_scope, tail) =>
-    { :params, :body, :scope } = @head\const!\unwrap 'fndef', "cant fn-invoke #{@head}"
+    { :params, :body, :scope } = @head\unwrap 'fndef', "cant fn-invoke #{@head}"
 
     assert #params == #tail, "argument count mismatch in #{@head}"
 
@@ -47,7 +48,7 @@ class fn_invoke extends Action
     result = body\eval fn_scope
 
     table.insert children, result
-    ResultNode :children, value: result.value
+    Result :children, value: result.value
 
 {
   :op_invoke, :fn_invoke
diff --git a/core/parsing.moon b/core/parsing.moon
index 96d8125..03ef85c 100644
--- a/core/parsing.moon
+++ b/core/parsing.moon
@@ -1,4 +1,4 @@
-import Const from require 'core.value'
+import Value from require 'core.value'
 import Cell, RootCell from require 'core.cell'
 import Tag from require 'core.tag'
 import R, S, P, V, C, Ct from require 'lpeg'
@@ -16,15 +16,15 @@ mspace = (comment + wc)^0 / 1            -- optional whitespace
 -- atoms
 digit = R '09'
 first = (R 'az', 'AZ') + S '-_+*/.!?='
-sym = first * (first + digit)^0 / Const\parse 'sym'
+sym = first * (first + digit)^0 / Value\parse 'sym'
 
-strd = '"' * (C ((P '\\"') + (P '\\\\') + (1 - P '"'))^0) * '"' / Const\parse 'str', '\"'
-strq = "'" * (C ((P "\\'") + (P '\\\\') + (1 - P "'"))^0) * "'" / Const\parse 'str', '\''
+strd = '"' * (C ((P '\\"') + (P '\\\\') + (1 - P '"'))^0) * '"' / Value\parse 'str', '\"'
+strq = "'" * (C ((P "\\'") + (P '\\\\') + (1 - P "'"))^0) * "'" / Value\parse 'str', '\''
 str = strd + strq
 
 int = digit^1
 float = (digit^1 * '.' * digit^0) + (digit^0 * '.' * digit^1)
-num = (float + int) / Const\parse 'num'
+num = (float + int) / Value\parse 'num'
 
 atom = num + sym + str
 
diff --git a/core/registry.moon b/core/registry.moon
index 4dd5bbb..e8272fa 100644
--- a/core/registry.moon
+++ b/core/registry.moon
@@ -1,7 +1,12 @@
+import Value from require 'core.value'
+
 class Registry
   new: () =>
     @map = {}
 
+    @tick = 0
+    @kr = Value.bool true
+
 -- methods for Tag
 
   last: (index) => @last_map[index]
@@ -15,37 +20,44 @@ class Registry
     L\trace "reg: init pending to #{expr}"
     table.insert @pending, { :tag, :expr }
 
-  active: ->
-    assert Registry.active_registry, "no active Registry!"
+  active: -> assert Registry.active_registry, "no active Registry!"
 
 -- public methods
 
-  wrap: (fn) =>
-    (...) ->
-      @prepare!
-      with fn ...
-        @finalize!
-
-  prepare: =>
-    assert not @prev, "already have a previous registry? #{@prev}"
-    @prev, @@active_registry = @@active_registry, @
+  wrap_eval: (fn) => (...) ->
+    @grab!
     @last_map, @map, @pending = @map, {}, {}
 
-  finalize: =>
-    for tag, val in pairs @last_map
-      if not @map[tag]
-        val\destroy!
+    with fn ...
+      for tag, val in pairs @last_map
+        if not @map[tag]
+          val\destroy!
 
-    for { :tag, :expr } in *@pending
-      -- tag was solved by another pending registration
-      -- (e.g. first [A] is solved, then [5.A] is solved)
-      continue if tag\index!
+      for { :tag, :expr } in *@pending
+        -- tag was solved by another pending registration
+        -- (e.g. first [A] is solved, then [5.A] is solved)
+        continue if tag\index!
 
-      next_tag = @next_tag!
-      L\trace "assigned new tag #{next_tag} to #{tag} #{expr}"
-      tag\set next_tag
-      @map[tag\index!] = expr
+        next_tag = @next_tag!
+        L\trace "assigned new tag #{next_tag} to #{tag} #{expr}"
+        tag\set next_tag
+        @map[tag\index!] = expr
+
+      @release!
+
+  wrap_tick: (fn) => (...) ->
+    @grab!
+    @tick += 1
+    @kr\set true
+
+    with fn ...
+      @release!
+
+  grab: =>
+    assert not @prev, "already have a previous registry? #{@prev}"
+    @prev, @@active_registry = @@active_registry, @
 
+  release: =>
     assert @ == @@active_registry, "not the active registry!"
     @@active_registry, @prev = @prev, nil
 
diff --git a/core/scope.moon b/core/scope.moon
index aaa38f2..f795f97 100644
--- a/core/scope.moon
+++ b/core/scope.moon
@@ -1,12 +1,16 @@
-import Value from require 'core.value'
+import Result, Value from require 'core.value'
 
 class Scope
   new: (@node, @parent) =>
     @values = {}
 
-  set_raw: (key, val) => @values[key] = Value.wrap val, key
+  set_raw: (key, val) =>
+    value = Value.wrap val, key
+    @values[key] = Result :value
+
   set: (key, val) =>
     L\trace "setting #{key} = #{val} in #{@}"
+    assert val.__class == Result, "expected #{key}=#{val} to be Result"
     @values[key] = val
 
   get: (key, prefix='') =>
@@ -20,9 +24,9 @@ class Scope
     if not start
       return @parent and L\push -> @parent\get key
 
-    scope = @get start
-    assert scope and scope.type == 'scope', "cant find '#{prefix}#{start}' for '#{prefix}#{key}'"
-    scope\unwrap!\get rest, "#{prefix}#{start}/"
+    child = @get start
+    assert child and child.value.type == 'scope', "#{start} is not a scope (looking for #{key})"
+    child.value\unwrap!\get rest, "#{prefix}#{start}/"
 
   use: (other) =>
     L\trace "using defs from #{other} in #{@}"
@@ -31,7 +35,8 @@ class Scope
 
   from_table: (tbl) ->
     with Scope!
-      .values = { k, Value.wrap v, k for k,v in pairs tbl }
+      for k, v in pairs tbl
+        \set_raw k, v
 
   __tostring: =>
     buf = "<Scope"
diff --git a/core/value.moon b/core/value.moon
index f3f9796..986c846 100644
--- a/core/value.moon
+++ b/core/value.moon
@@ -1,9 +1,9 @@
 -- ALV Value types
-import Op, Action, FnDef from require 'core.base'
-
-local Scope
+local Scope, Registry, Op, Action, FnDef
 load_ = ->
   import Scope from require 'core.scope'
+  import Registry from require 'core.registry'
+  import Op, Action, FnDef from require 'core.base'
 
 ancestor = (klass) ->
   assert klass, "cant find the ancestor of nil"
@@ -16,26 +16,73 @@ ancestor = (klass) ->
 -- - a Value
 -- - an Op (to update)
 -- - children (results of subexpressions that were evaluated)
+-- - cached list of all Dispatchers affecting all Ops in the subtree
 --
--- ResultNodes form a tree that controls execution order and message passing
+-- Results form a tree that controls execution order and message passing
 -- between Ops.
-class ResultNode
+class Result
   -- params: table with optional keys op, value, children
   new: (params={}) =>
-    @op = params.op
     @value = params.value
+    @op = params.op
     @children = params.children or {}
 
-  -- unwrap value and assert that neither @op nor @children were set
-  value_only: (msg) =>
-    assert not @op and #@children == 0, msg or "pure expression expected"
+    @all_impulses = {}
+    for child in *@children
+      for d in pairs child.all_impulses
+        @all_impulses[d] = true
+
+    if @op
+      assert @op.impulses, "#{@op} not set up correctly (impulses)"
+      for d in *@op.impulses
+        @all_impulses[d] = true
+
+  -- asserts value-constness and returns the value
+  const: (msg) =>
+    assert not (next @all_impulses), msg or "eval-time const expected"
     @value
 
-  update: (dt) =>
+  -- create a value-copy of this result that has the same impulses but without
+  -- affecting the original's update logic
+  make_ref: =>
+    with Result value: @value
+      .all_impulses = @all_impulses
+
+  -- in depth-first order, tick all Ops who have dirty Stream inputs or impulses
+  --
+  -- short-circuits if there are no dirty Streams in the entire subtree
+  tick: =>
+    any_dirty = false
+    for stream in pairs @all_impulses
+      if stream\dirty!
+        any_dirty = true
+        break
+
+    -- early-out if no streams are dirty in this whole subtree
+    return unless any_dirty
+
     for child in *@children
-      child\update dt
-    @op\update dt if @op
+      child\tick!
+
+    if @op
+      -- we have to check self_dirty here, because streams from child
+      -- expressions might have changed
+      self_dirty = false
+      for stream in *@op.impulses
+        if stream\dirty!
+          self_dirty = true
+          break
+      for stream in *@op.inputs
+        if stream\dirty!
+          self_dirty = true
+          break
+
+      L\trace "#{op} is #{if self_dirty then 'dirty' else 'clean'}"
+      return unless self_dirty
+
+      @op\tick!
 
+-- static
   __tostring: =>
     buf = "<result=#{@value}"
     buf ..= " #{@op}" if @op
@@ -43,19 +90,18 @@ class ResultNode
     buf ..= ">"
     buf
 
-local Const, Stream
-
 -- ALV Type wrapper
 class Value
   -- @type      - type name.
   --              builtin types: * literals: sym, num, bool
   --                             * scope, opdef, fndef, builtin
   -- @value     - Lua value - access through :unwrap()
-  new: (@type, @value) =>
+  new: (@type, @value, @raw) =>
+    @updated = 0
 
-  -- asserts value-constness
-  -- returns self (for chaining)
-  const: => error 'not a constant'
+  dirty: => @updated == Registry.active!.tick
+
+  set: (@value) => @updated = Registry.active!.tick
 
   -- unwrap to the Lua type
   -- asserts @type == type, msg if given
@@ -63,14 +109,30 @@ class Value
     assert type == @type, msg or "#{@} is not a #{type}" if type
     @value
 
+-- AST interface
+  eval: (scope) =>
+    switch @type
+      when 'num', 'str'
+        Result value: @
+      when 'sym'
+        assert (scope\get @value), "undefined reference to symbol '#{@value}'"
+      else
+        error "cannot evaluate #{@}"
+
+  quote: => @
+
+  stringify: => assert @raw, "stringifying Value that wasn't parsed"
+
+  clone: (prefix) => @
+  -- in case of doubt:
+  -- clone: (prefix) => Value @type, @value, @raw
+
 -- static
   __tostring: =>
     value = if 'table' == (type @value) and rawget @value, '__base' then @value.__name else @value
     "<#{@@__name} #{@type}: #{value}>"
+  __call: (...) => @unwrap ...
   __eq: (other) => other.type == @type and other.value == @value
-  __inherited: (cls) =>
-    cls.__base.__tostring = @__tostring
-    cls.__base.__eq = @__eq
 
   -- wrap a Lua type
   @wrap: (val, name='(unknown)') ->
@@ -96,62 +158,26 @@ class Value
               error "#{name}: cannot wrap '#{val.__class.__name}' instance"
         else
           -- plain table
-          return Const 'scope', Scope.from_table val
+          return Value 'scope', Scope.from_table val
       else
         error "#{name}: cannot wrap Lua type '#{type val}'"
 
-    Const typ, val
-
-class Stream extends Value
-  new: (@type, @value=nil) =>
-
-  set: (@value) =>
-    -- set dirty flag (?)
-
-class Const extends Value
-  new: (type, value, @raw) =>
-    super type, value
-
--- Value interface
-  const: => @
-
--- AST interface
-  eval: (scope) =>
-    value = switch @type
-      when 'num', 'str'
-        @
-      when 'sym'
-        assert (scope\get @value), "undefined reference to symbol '#{@value}'"
-      else
-        error "cannot evaluate #{@}"
-
-    ResultNode :value
-
-  quote: => @
-
-  stringify: => @raw
+    Value typ, val
 
-  clone: (prefix) => @
-  -- in case of doubt:
-  -- clone: (prefix) => Const @type, @value, @raw
-
--- static
   unescape = (str) -> str\gsub '\\([\'"\\])', '%1'
-
   @parse: (type, sep) =>
     switch type
       when 'num' then (match) -> @ 'num', (tonumber match), match
       when 'sym' then (match) -> @ 'sym', match, match
       when 'str' then (match) -> @ 'str', (unescape match), sep .. match .. sep
 
-  @num: (num) -> Const 'num', num, tostring num
-  @str: (str) -> Const 'str', str, "'#{str}'"
-  @sym: (sym) -> Const 'sym', sym, sym
-  @bool: (bool) -> Const 'bool', bool, tostring bool
+  @num: (num) -> Value 'num', num, tostring num
+  @str: (str) -> Value 'str', str, "'#{str}'"
+  @sym: (sym) -> Value 'sym', sym, sym
+  @bool: (bool) -> Value 'bool', bool, tostring bool
 
 {
-  :ResultNode
+  :Result
   :Value
-  :Stream, :Const
   :load_
 }