1 files changed, 55 insertions, 0 deletions
diff --git a/core/scope.moon b/core/scope.moon
new file mode 100644
index 0000000..a840ba7
--- /dev/null
+++ b/core/scope.moon
@@ -0,0 +1,55 @@
+import Const from require 'core.const'
+
+class Scope
+  new: (@node, @parent) =>
+    @values = {}
+
+  set_raw: (key, val) => @values[key] = Const.wrap val, key
+  set: (key, val) =>
+    L\trace "setting #{key} = #{val} in #{@}"
+    @values[key] = val
+
+  get: (key, prefix='') =>
+    L\debug "checking for #{key} in #{@}"
+    if val = @values[key]
+      L\trace "found #{val} in #{@}"
+      return val
+
+    start, rest = key\match '^(.-)/(.*)'
+
+    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\getc!\get rest, "#{prefix}#{start}/"
+
+  use: (other) =>
+    for k, v in pairs other.values
+      @values[k] = v
+
+  from_table: (tbl) ->
+    with Scope!
+      .values = { k, Const.wrap v, k for k,v in pairs tbl }
+
+  __tostring: =>
+    buf = "<Scope"
+    buf ..= "@#{@node}" if @node
+
+    depth = -1
+    parent = @parent
+    while parent
+      depth += 1
+      parent = parent.parent
+    buf ..= " ^#{depth}" if depth != 0
+
+    keys = [key for key in pairs @values]
+    if #keys > 5
+      keys = [key for key in *keys[,5]]
+      keys[6] = '...'
+    buf ..= " [#{table.concat keys, ', '}]"
+
+    buf ..= ">"
+    buf
+
+:Scope