new Registry tagging mechanism

1 files changed, 114 insertions, 0 deletions

diff --git a/core/registry.moon b/core/registry.moon
new file mode 100644
index 0000000..7c89fa4
--- /dev/null
+++ b/core/registry.moon
@@ -0,0 +1,114 @@
+import Const from require 'core.const'
+import Scope from require 'core.scope'
+
+local ClonedTag
+
+class Tag
+  new: (@value) =>
+
+  clone: (parent) => ClonedTag @, parent
+
+  last: =>
+    if index = @index!
+      @registry\last index
+
+  keep: (expr) =>
+    index = assert @index!
+    assert expr == @registry\last index
+    @registry\replace index, expr
+
+  replace: (expr) =>
+    if index = @index!
+      @registry\replace index, expr
+    else
+      @registry\init @, expr
+
+index: => @value
+
+  set: (value) =>
+    assert not @value, "setting #{@} again"
+    @value = value
+
+  @blank: -> Tag!
+  @parse: (num) => @ tonumber num
+
+  stringify: => if @value then "[#{@value}]" else ''
+
+  __tostring: => if @value then "#{@value}" else '[blank]'
+
+class ClonedTag extends Tag
+  class DummyReg
+    destroy: =>
+
+  new: (@original, @parent) =>
+    @registry = @original.registry
+    @dummy = DummyReg!
+
+  keep: (expr) =>
+    super\keep expr
+    @original.registry or= @registry
+    @original\replace @dummy
+
+  replace: (expr) =>
+    super\replace expr
+    @original.registry or= @registry
+    @original\replace @dummy
+
+  index: =>
+    orig = @original\index!
+    parent = @parent\index!
+    if orig and parent
+      "#{parent}.#{orig}"
+
+  set: (value) => @original\set value
+
+  stringify: => error "cant stringify ClonedTag"
+
+  __tostring: =>
+    if @parent
+      "#{@parent}.#{@original}"
+    else
+      tostring @original
+
+class Registry
+  new: () =>
+    @map = {}
+
+-- methods for Tag
+
+  last: (index) => @last_map[index]
+
+  replace: (index, expr) =>
+    L\trace "reg: setting #{index} to #{expr}"
+    assert not @map[index], "duplicate tags with index #{index}!"
+    @map[index] = expr
+
+  init: (tag, expr) =>
+    L\trace "reg: init pending to #{expr}"
+    table.insert @pending, { :tag, :expr }
+
+-- public methods
+
+  prepare: =>
+    @last_map, @map, @pending = @map, {}, {}
+
+  finalize: =>
+    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!
+
+      L\trace "assigning new tag #{value} to #{tag} #{expr}"
+      tag\set @next_tag!
+      @map[tag\index!] = expr
+
+  next_tag: => #@map + 1
+
+{
+  :Tag
+  :Registry
+}