From 7321c1717128d8904f1c7862fb782250fdba6d92 Mon Sep 17 00:00:00 2001
From: Brian Anderson <banderson@mozilla.com>
Date: Sun, 22 Apr 2012 15:15:18 -0700
Subject: [PATCH] syntax: Eliminate token::POUND_LT, POUND_LBRACE

Use lookahead in the parser
---
 src/librustsyntax/parse/lexer.rs  |  7 +------
 src/librustsyntax/parse/parser.rs | 14 ++++++++------
 src/librustsyntax/parse/token.rs  |  4 ----
 3 files changed, 9 insertions(+), 16 deletions(-)

diff --git a/src/librustsyntax/parse/lexer.rs b/src/librustsyntax/parse/lexer.rs
index dc5de0ad7bb..a7b109f2324 100644
--- a/src/librustsyntax/parse/lexer.rs
+++ b/src/librustsyntax/parse/lexer.rs
@@ -357,12 +357,7 @@ fn next_token_inner(rdr: reader) -> token::token {
       '[' { rdr.bump(); ret token::LBRACKET; }
       ']' { rdr.bump(); ret token::RBRACKET; }
       '@' { rdr.bump(); ret token::AT; }
-      '#' {
-        rdr.bump();
-        if rdr.curr == '<' { rdr.bump(); ret token::POUND_LT; }
-        if rdr.curr == '{' { rdr.bump(); ret token::POUND_LBRACE; }
-        ret token::POUND;
-      }
+      '#' { rdr.bump(); ret token::POUND; }
       '~' { rdr.bump(); ret token::TILDE; }
       ':' {
         rdr.bump();
diff --git a/src/librustsyntax/parse/parser.rs b/src/librustsyntax/parse/parser.rs
index 46ccb09b220..44d71fb3657 100644
--- a/src/librustsyntax/parse/parser.rs
+++ b/src/librustsyntax/parse/parser.rs
@@ -710,7 +710,8 @@ fn parse_bottom_expr(p: parser) -> pexpr {
                              parse_expr, p);
         hi = p.span.hi;
         ex = ast::expr_vec(es, mutbl);
-    } else if p.token == token::POUND_LT {
+    } else if p.token == token::POUND && p.look_ahead(1u) == token::LT {
+        p.bump();
         p.bump();
         let ty = parse_ty(p, false);
         expect(p, token::GT);
@@ -718,7 +719,8 @@ fn parse_bottom_expr(p: parser) -> pexpr {
         /* hack: early return to take advantage of specialized function */
         ret pexpr(mk_mac_expr(p, lo, p.span.hi,
                               ast::mac_embed_type(ty)));
-    } else if p.token == token::POUND_LBRACE {
+    } else if p.token == token::POUND && p.look_ahead(1u) == token::LBRACE {
+        p.bump();
         p.bump();
         let blk = ast::mac_embed_block(
             parse_block_tail(p, lo, ast::default_blk));
@@ -726,6 +728,10 @@ fn parse_bottom_expr(p: parser) -> pexpr {
     } else if p.token == token::ELLIPSIS {
         p.bump();
         ret pexpr(mk_mac_expr(p, lo, p.span.hi, ast::mac_ellipsis));
+    } else if p.token == token::POUND {
+        let ex_ext = parse_syntax_ext(p);
+        hi = ex_ext.span.hi;
+        ex = ex_ext.node;
     } else if eat_word(p, "bind") {
         let e = parse_expr_res(p, RESTRICT_NO_CALL_EXPRS);
         let es =
@@ -733,10 +739,6 @@ fn parse_bottom_expr(p: parser) -> pexpr {
                       parse_expr_or_hole, p);
         hi = es.span.hi;
         ex = ast::expr_bind(e, es.node);
-    } else if p.token == token::POUND {
-        let ex_ext = parse_syntax_ext(p);
-        hi = ex_ext.span.hi;
-        ex = ex_ext.node;
     } else if eat_word(p, "fail") {
         if can_begin_expr(p.token) {
             let e = parse_expr(p);
diff --git a/src/librustsyntax/parse/token.rs b/src/librustsyntax/parse/token.rs
index c594d3e1ead..0088b7c4729 100644
--- a/src/librustsyntax/parse/token.rs
+++ b/src/librustsyntax/parse/token.rs
@@ -53,8 +53,6 @@ enum token {
     LBRACE,
     RBRACE,
     POUND,
-    POUND_LBRACE,
-    POUND_LT,
 
     DOLLAR_LPAREN,
     DOLLAR_NUM(uint),
@@ -124,8 +122,6 @@ fn to_str(in: interner<str>, t: token) -> str {
       LBRACE { ret "{"; }
       RBRACE { ret "}"; }
       POUND { ret "#"; }
-      POUND_LBRACE { ret "#{"; }
-      POUND_LT { ret "#<"; }
 
       DOLLAR_LPAREN { ret "$("; }
       DOLLAR_NUM(u) {