---

yaml
---
r: 40571
b: refs/heads/dist-snap
c: 9845a4b
h: refs/heads/master
i:
  40569: ecdb039
  40567: 7cb24c6
v: v3

Author: paulstansifer

[refs]

@@ -7,7 +7,7 @@ refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105
 refs/heads/ndm: f3868061cd7988080c30d6d5bf352a5a5fe2460b
 refs/heads/try2: a810c03263670238bccd64cabb12a23a46e3a278
 refs/heads/incoming: e90142e536c150df0d9b4b2f11352152177509b5
-refs/heads/dist-snap: c946c87b6f9cd536309dfba09abdc9af32729f34
+refs/heads/dist-snap: 9845a4be5a4f9919fcadfb1076d2425781eab41f
 refs/tags/release-0.2: c870d2dffb391e14efb05aa27898f1f6333a9596
 refs/tags/release-0.3: b5f0d0f648d9a6153664837026ba1be43d3e2503
 refs/heads/try3: 9387340aab40a73e8424c48fd42f0c521a4875c0

branches/dist-snap/src/libsyntax/ext/base.rs

@@ -44,6 +44,7 @@ type syntax_expander_tt_item_
 enum mac_result {
     mr_expr(@ast::expr),
     mr_item(@ast::item),
+    mr_expr_or_item(fn@()-> @ast::expr, fn@()-> Option<@ast::item>),
     mr_def(macro_def)
 }
 

branches/dist-snap/src/libsyntax/ext/expand.rs

@@ -81,6 +81,7 @@ fn expand_expr(exts: HashMap<~str, syntax_extension>, cx: ext_ctxt,
                   Some(expr_tt({expander: exp, span: exp_sp})) => {
                     let expanded = match exp(cx, mac.span, tts) {
                       mr_expr(e) => e,
+                      mr_expr_or_item(expr_maker,_) => expr_maker(),
                       _ => cx.span_fatal(
                           pth.span, fmt!("non-expr macro in expr pos: %s",
                                          *extname))
@@ -214,6 +215,8 @@ fn expand_item_mac(exts: HashMap<~str, syntax_extension>,
               mr_expr(_) => cx.span_fatal(pth.span,
                                          ~"expr macro in item position: " +
                                          *extname),
+              mr_expr_or_item(_, item_maker) =>
+                option::chain(item_maker(), |i| {fld.fold_item(i)}),
               mr_def(mdef) => {
                 exts.insert(mdef.name, mdef.ext);
                 None

branches/dist-snap/src/libsyntax/ext/tt/macro_rules.rs

@@ -1,4 +1,4 @@
-use base::{ext_ctxt, mac_result, mr_expr, mr_def, expr_tt};
+use base::{ext_ctxt, mac_result, mr_expr_or_item, mr_def, expr_tt};
 use codemap::span;
 use ast::{ident, matcher_, matcher, match_tok,
              match_nonterminal, match_seq, tt_delim};
@@ -87,10 +87,13 @@ fn add_new_extension(cx: ext_ctxt, sp: span, name: ident,
                     // rhs has holes ( `$id` and `$(...)` that need filled)
                     let trncbr = new_tt_reader(s_d, itr, Some(named_matches),
                                                ~[rhs]);
-                    let p = Parser(cx.parse_sess(), cx.cfg(),
-                                   trncbr as reader);
-                    let e = p.parse_expr();
-                    return mr_expr(e);
+                    let p = @Parser(cx.parse_sess(), cx.cfg(),
+                                    trncbr as reader);
+
+                    // Let the context choose how to interpret the result.
+                    // Weird, but useful for X-macros.
+                    return mr_expr_or_item(|| p.parse_expr(),
+                                           || p.parse_item(~[/* no attrs*/]));
                   }
                   failure(sp, msg) => if sp.lo >= best_fail_spot.lo {
                     best_fail_spot = sp;