Use different syntax for checks that matter to typestate

This giant commit changes the syntax of Rust to use "assert" for
"check" expressions that didn't mean anything to the typestate
system, and continue using "check" for checks that are used as
part of typestate checking.

Most of the changes are just replacing "check" with "assert" in test
cases and rustc.

5 files changed, 38 insertions, 28 deletions

diff --git a/src/comp/front/ast.rs b/src/comp/front/ast.rs
index 2fd13194..13b5739e 100644
--- a/src/comp/front/ast.rs
+++ b/src/comp/front/ast.rs
@@ -283,7 +283,10 @@ tag expr_ {
     expr_put(option.t[@expr], ann);
     expr_be(@expr, ann);
     expr_log(int, @expr, ann);
-    expr_check_expr(@expr, ann);
+/* just an assert, no significance to typestate */
+    expr_assert(@expr, ann);
+/* preds that typestate is aware of */
+    expr_check(@expr, ann);
     expr_port(ann);
     expr_chan(@expr, ann);
 }
diff --git a/src/comp/front/creader.rs b/src/comp/front/creader.rs
index f48d47c9..c8b31159 100644
--- a/src/comp/front/creader.rs
+++ b/src/comp/front/creader.rs
@@ -93,7 +93,7 @@ fn parse_ty(@pstate st, str_def sd) -> ty.t {
         case ('c') { ret ty.mk_char(st.tcx); }
         case ('s') { ret ty.mk_str(st.tcx); }
         case ('t') {
-            check(next(st) as char == '[');
+            assert (next(st) as char == '[');
             auto def = parse_def(st, sd);
             let vec[ty.t] params = vec();
             while (peek(st) as char != ']') {
@@ -108,7 +108,7 @@ fn parse_ty(@pstate st, str_def sd) -> ty.t {
         case ('P') { ret ty.mk_port(st.tcx, parse_ty(st, sd)); }
         case ('C') { ret ty.mk_chan(st.tcx, parse_ty(st, sd)); }
         case ('T') {
-            check(next(st) as char == '[');
+            assert (next(st) as char == '[');
             let vec[ty.mt] params = vec();
             while (peek(st) as char != ']') {
                 params += vec(parse_mt(st, sd));
@@ -117,7 +117,7 @@ fn parse_ty(@pstate st, str_def sd) -> ty.t {
             ret ty.mk_tup(st.tcx, params);
         }
         case ('R') {
-            check(next(st) as char == '[');
+            assert (next(st) as char == '[');
             let vec[ty.field] fields = vec();
             while (peek(st) as char != ']') {
                 auto name = "";
@@ -149,7 +149,7 @@ fn parse_ty(@pstate st, str_def sd) -> ty.t {
             ret ty.mk_native_fn(st.tcx,abi,func._0,func._1);
         }
         case ('O') {
-            check(next(st) as char == '[');
+            assert (next(st) as char == '[');
             let vec[ty.method] methods = vec();
             while (peek(st) as char != ']') {
                 auto proto;
@@ -175,9 +175,9 @@ fn parse_ty(@pstate st, str_def sd) -> ty.t {
         case ('Y') { ret ty.mk_type(st.tcx); }
         case ('#') {
             auto pos = parse_hex(st);
-            check (next(st) as char == ':');
+            assert (next(st) as char == ':');
             auto len = parse_hex(st);
-            check (next(st) as char == '#');
+            assert (next(st) as char == '#');
             alt (st.tcx.rcache.find(tup(st.crate,pos,len))) {
                 case (some[ty.t](?tt)) { ret tt; }
                 case (none[ty.t]) {
@@ -245,7 +245,7 @@ fn parse_hex(@pstate st) -> uint {
 }
 
 fn parse_ty_fn(@pstate st, str_def sd) -> tup(vec[ty.arg], ty.t) {
-    check(next(st) as char == '[');
+    assert (next(st) as char == '[');
     let vec[ty.arg] inputs = vec();
     while (peek(st) as char != ']') {
         auto mode = ast.val;
diff --git a/src/comp/front/lexer.rs b/src/comp/front/lexer.rs
index 3659af1c..dabdee1c 100644
--- a/src/comp/front/lexer.rs
+++ b/src/comp/front/lexer.rs
@@ -127,6 +127,7 @@ fn keyword_table() -> std.map.hashmap[str, token.token] {
 
     keywords.insert("type", token.TYPE);
     keywords.insert("check", token.CHECK);
+    keywords.insert("assert", token.ASSERT);
     keywords.insert("claim", token.CLAIM);
     keywords.insert("prove", token.PROVE);
 
@@ -528,7 +529,7 @@ fn scan_numeric_escape(reader rdr) -> char {
 
     auto n_hex_digits = 0;
 
-    check (rdr.curr() == '\\');
+    assert (rdr.curr() == '\\');
 
     alt (rdr.next()) {
         case ('x') { n_hex_digits = 2; }
diff --git a/src/comp/front/parser.rs b/src/comp/front/parser.rs
index fdd41cf0..3e8ca85a 100644
--- a/src/comp/front/parser.rs
+++ b/src/comp/front/parser.rs
@@ -621,7 +621,7 @@ fn parse_path(parser p, greed g) -> ast.path {
                 if (p.peek() == token.DOT) {
                     if (g == GREEDY) {
                         p.bump();
-                        check (is_ident(p.peek()));
+                        assert (is_ident(p.peek()));
                     } else {
                         more = false;
                     }
@@ -816,20 +816,23 @@ fn parse_bottom_expr(parser p) -> @ast.expr {
             ex = ast.expr_log(0, e, ast.ann_none);
         }
 
-        case (token.CHECK) {
+        case (token.ASSERT) {
             p.bump();
-            alt (p.peek()) {
-                case (token.LPAREN) {
-                    auto e = parse_expr(p);
-                    auto hi = e.span.hi;
-                    ex = ast.expr_check_expr(e, ast.ann_none);
-                }
-                case (_) {
-                    p.get_session().unimpl("constraint-check stmt");
-                }
-            }
+            auto e = parse_expr(p);
+            auto hi = e.span.hi;
+            ex = ast.expr_assert(e, ast.ann_none);
         }
 
+        case (token.CHECK) {
+            p.bump();
+            /* Should be a predicate (pure boolean function) applied to 
+             arguments that are all either slot variables or literals.
+            but the typechecker enforces that. */
+            auto e = parse_expr(p);
+            auto hi = e.span.hi;
+            ex = ast.expr_check(e, ast.ann_none);
+        } 
+
         case (token.RET) {
             p.bump();
             alt (p.peek()) {
@@ -937,7 +940,7 @@ fn expand_syntax_ext(parser p, ast.span sp,
                      &ast.path path, vec[@ast.expr] args,
                      option.t[str] body) -> ast.expr_ {
 
-    check (_vec.len[ast.ident](path.node.idents) > 0u);
+    assert (_vec.len[ast.ident](path.node.idents) > 0u);
     auto extname = path.node.idents.(0);
     if (_str.eq(extname, "fmt")) {
         auto expanded = extfmt.expand_syntax_ext(args, body);
@@ -1673,7 +1676,8 @@ fn stmt_ends_with_semi(@ast.stmt stmt) -> bool {
                 case (ast.expr_put(_,_))        { ret true; }
                 case (ast.expr_be(_,_))         { ret true; }
                 case (ast.expr_log(_,_,_))        { ret true; }
-                case (ast.expr_check_expr(_,_)) { ret true; }
+                case (ast.expr_check(_,_)) { ret true; }
+                case (ast.expr_assert(_,_)) { ret true; }
             }
         }
         // We should not be calling this on a cdir.
@@ -2157,24 +2161,24 @@ fn parse_item(parser p) -> @ast.item {
 
     alt (p.peek()) {
         case (token.CONST) {
-            check (lyr == ast.layer_value);
+            assert (lyr == ast.layer_value);
             ret parse_item_const(p);
         }
 
         case (token.FN) {
-            check (lyr == ast.layer_value);
+            assert (lyr == ast.layer_value);
             ret parse_item_fn_or_iter(p);
         }
         case (token.ITER) {
-            check (lyr == ast.layer_value);
+            assert (lyr == ast.layer_value);
             ret parse_item_fn_or_iter(p);
         }
         case (token.MOD) {
-            check (lyr == ast.layer_value);
+            assert (lyr == ast.layer_value);
             ret parse_item_mod(p);
         }
         case (token.NATIVE) {
-            check (lyr == ast.layer_value);
+            assert (lyr == ast.layer_value);
             ret parse_item_native_mod(p);
         }
         case (token.TYPE) {
diff --git a/src/comp/front/token.rs b/src/comp/front/token.rs
index f367bcc6..594515f2 100644
--- a/src/comp/front/token.rs
+++ b/src/comp/front/token.rs
@@ -89,6 +89,7 @@ tag token {
 
     /* Type and type-state keywords */
     TYPE;
+    ASSERT;
     CHECK;
     CLAIM;
     PROVE;
@@ -258,6 +259,7 @@ fn to_str(token t) -> str {
 
         /* Type and type-state keywords */
         case (TYPE) { ret "type"; }
+        case (ASSERT) { ret "assert"; }
         case (CHECK) { ret "check"; }
         case (CLAIM) { ret "claim"; }
         case (PROVE) { ret "prove"; }