---

yaml
---
r: 79501
b: refs/heads/snap-stage3
c: 985a92e
h: refs/heads/master
i:
  79499: 42d762c
v: v3

Author: jbclements

[refs]

@@ -1,7 +1,7 @@
 ---
 refs/heads/master: 124eb2119c78651cfaaa7a046a101fa2e20f83ca
 refs/heads/snap-stage1: e33de59e47c5076a89eadeb38f4934f58a3618a6
-refs/heads/snap-stage3: 1a065841172a0824046b1f041bdb1134ba820db8
+refs/heads/snap-stage3: 985a92ec123ff05a361bde6af4602282e3851d77
 refs/heads/try: ac820906c0e53eab79a98ee64f7231f57c3887b4
 refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105
 refs/heads/ndm: f3868061cd7988080c30d6d5bf352a5a5fe2460b

branches/snap-stage3/src/libsyntax/ast.rs

@@ -81,6 +81,15 @@ impl Ident {
 // storage.
 pub type SyntaxContext = uint;
 
+// the SCTable contains a table of SyntaxContext_'s. It
+// represents a flattened tree structure, to avoid having
+// managed pointers everywhere (that caused an ICE).
+// the mark_memo and rename_memo fields are side-tables
+// that ensure that adding the same mark to the same context
+// gives you back the same context as before. This shouldn't
+// change the semantics--everything here is immutable--but
+// it should cut down on memory use *a lot*; applying a mark
+// to a tree containing 50 identifiers would otherwise generate
 pub struct SCTable {
     table : ~[SyntaxContext_],
     mark_memo : HashMap<(SyntaxContext,Mrk),SyntaxContext>,