From 792436826892d61ca16797fe3d26b1f202f6702a Mon Sep 17 00:00:00 2001
From: Brian Anderson <banderson@mozilla.com>
Date: Wed, 31 Aug 2011 22:34:41 -0700
Subject: [PATCH] Allow istrs as patterns. Issue #855

---
 src/comp/middle/trans_alt.rs    | 14 +++++++++-----
 src/comp/syntax/parse/parser.rs | 16 ++++++++++++++++
 src/test/run-pass/alt-str.rs    | 34 ++++++++++++++++++++++++---------
 3 files changed, 50 insertions(+), 14 deletions(-)

diff --git a/src/comp/middle/trans_alt.rs b/src/comp/middle/trans_alt.rs
index 76f4ef1ec0b..6dddf42caeb 100644
--- a/src/comp/middle/trans_alt.rs
+++ b/src/comp/middle/trans_alt.rs
@@ -296,9 +296,9 @@ fn compile_submatch(bcx: @block_ctxt, m: &match, vals: [ValueRef],
         let data = m[0].data;
         alt data.guard {
           some(e) {
-            let guard_cx = new_scope_block_ctxt(bcx, ~"guard");
-            let next_cx = new_sub_block_ctxt(bcx, ~"next");
-            let else_cx = new_sub_block_ctxt(bcx, ~"else");
+            let guard_cx = new_scope_block_ctxt(bcx, ~"submatch_guard");
+            let next_cx = new_sub_block_ctxt(bcx, ~"submatch_next");
+            let else_cx = new_sub_block_ctxt(bcx, ~"submatch_else");
             Br(bcx, guard_cx.llbb);
             // Temporarily set bindings. They'll be rewritten to PHI nodes for
             // the actual arm block.
@@ -431,13 +431,17 @@ fn compile_submatch(bcx: @block_ctxt, m: &match, vals: [ValueRef],
             llvm::LLVMAddCase(sw, r.val, opt_cx.llbb);
           }
           compare. {
+            let compare_cx = new_scope_block_ctxt(bcx, ~"compare_scope");
+            Br(bcx, compare_cx.llbb);
+            bcx = compare_cx;
             let r = trans_opt(bcx, opt);
             bcx = r.bcx;
             let t = ty::node_id_to_type(ccx.tcx, pat_id);
             let eq =
                 trans::trans_compare(bcx, ast::eq, test_val, t, r.val, t);
-            bcx = new_sub_block_ctxt(bcx, ~"next");
-            CondBr(eq.bcx, eq.val, opt_cx.llbb, bcx.llbb);
+            let cleanup_cx = trans::trans_block_cleanups(bcx, compare_cx);
+            bcx = new_sub_block_ctxt(bcx, ~"compare_next");
+            CondBr(cleanup_cx, eq.val, opt_cx.llbb, bcx.llbb);
           }
           _ { }
         }
diff --git a/src/comp/syntax/parse/parser.rs b/src/comp/syntax/parse/parser.rs
index 369e07080f4..9c61f569e21 100644
--- a/src/comp/syntax/parse/parser.rs
+++ b/src/comp/syntax/parse/parser.rs
@@ -1497,6 +1497,22 @@ fn parse_pat(p: &parser) -> @ast::pat {
             pat = ast::pat_tup(fields);
         }
       }
+      token::TILDE. {
+        p.bump();
+        alt p.peek() {
+          token::LIT_STR(s) {
+            let sp = p.get_span();
+            p.bump();
+            let lit =
+                @{node: ast::lit_str(p.get_str(s),
+                                     ast::sk_unique),
+                  span: sp};
+            hi = lit.span.hi;
+            pat = ast::pat_lit(lit);
+          }
+          _ { p.fatal(~"expected string literal"); }
+        }
+      }
       tok {
         if !is_ident(tok) || is_word(p, ~"true") || is_word(p, ~"false") {
             let lit = parse_lit(p);
diff --git a/src/test/run-pass/alt-str.rs b/src/test/run-pass/alt-str.rs
index fbdf7fdbfe3..57e68552e80 100644
--- a/src/test/run-pass/alt-str.rs
+++ b/src/test/run-pass/alt-str.rs
@@ -1,15 +1,31 @@
 // Issue #53
 
 fn main() {
-    alt "test" { "not-test" { fail; } "test" { } _ { fail; } }
-
-    tag t { tag1(str); tag2; }
-
-
-    alt tag1("test") {
-      tag2. { fail; }
-      tag1("not-test") { fail; }
-      tag1("test") { }
+    alt ~"test" {
+      ~"not-test" { fail; }
+      ~"test" { }
       _ { fail; }
     }
+
+    tag t { tag1(istr); tag2; }
+
+
+    alt tag1(~"test") {
+      tag2. { fail; }
+      tag1(~"not-test") { fail; }
+      tag1(~"test") { }
+      _ { fail; }
+    }
+
+    let x = alt ~"a" {
+      ~"a" { 1 }
+      ~"b" { 2 }
+    };
+    assert x == 1;
+
+    alt ~"a" {
+      ~"a" { }
+      ~"b" { }
+    }
+
 }