Parse and report obsolete fixed-length vector syntax

Author: brson

src/libsyntax/parse/obsolete.rs

@@ -23,7 +23,8 @@ pub enum ObsoleteSyntax {
     ObsoleteClassTraits,
     ObsoletePrivSection,
     ObsoleteModeInFnType,
-    ObsoleteByMutRefMode
+    ObsoleteByMutRefMode,
+    ObsoleteFixedLengthVec,
 }
 
 impl ObsoleteSyntax : cmp::Eq {
@@ -99,6 +100,11 @@ impl Parser : ObsoleteReporter {
                 "by-mutable-reference mode",
                 "Declare an argument of type &mut T instead"
             ),
+            ObsoleteFixedLengthVec => (
+                "fixed-length vector",
+                "Fixed-length types are now written `[T * N]`, and instances \
+                 are type-inferred"
+            )
         };
 
         self.report(sp, kind, kind_str, desc);
@@ -183,5 +189,66 @@ impl Parser : ObsoleteReporter {
             false
         }
     }
+
+    fn try_parse_obsolete_fixed_vstore() -> Option<Option<uint>> {
+        if self.token == token::BINOP(token::SLASH) {
+            self.bump();
+            match copy self.token {
+                token::UNDERSCORE => {
+                    self.obsolete(copy self.last_span,
+                                  ObsoleteFixedLengthVec);
+                    self.bump(); Some(None)
+                }
+                token::LIT_INT_UNSUFFIXED(i) if i >= 0i64 => {
+                    self.obsolete(copy self.last_span,
+                                  ObsoleteFixedLengthVec);
+                    self.bump(); Some(Some(i as uint))
+                }
+                _ => None
+            }
+        } else {
+            None
+        }
+    }
+
+    fn try_convert_ty_to_obsolete_fixed_length_vstore(sp: span, t: ast::ty_)
+        -> ast::ty_ {
+        match self.try_parse_obsolete_fixed_vstore() {
+            // Consider a fixed length vstore suffix (/N or /_)
+            None => t,
+            Some(v) => {
+                ast::ty_fixed_length(
+                    @{id: self.get_id(), node: t, span: sp}, v)
+            }
+        }
+    }
+
+    fn try_convert_expr_to_obsolete_fixed_length_vstore(
+        lo: uint, hi: uint, ex: ast::expr_
+    ) -> (uint, ast::expr_) {
+
+        let mut hi = hi;
+        let mut ex = ex;
+
+        // Vstore is legal following expr_lit(lit_str(...)) and expr_vec(...)
+        // only.
+        match ex {
+            ast::expr_lit(@{node: ast::lit_str(_), span: _}) |
+            ast::expr_vec(_, _)  => {
+                match self.try_parse_obsolete_fixed_vstore() {
+                    None => (),
+                    Some(v) => {
+                        hi = self.span.hi;
+                        ex = ast::expr_vstore(self.mk_expr(lo, hi, ex),
+                                              ast::expr_vstore_fixed(v));
+                    }
+                }
+            }
+            _ => ()
+        }
+
+        return (hi, ex);
+    }
+
 }
 

src/libsyntax/parse/parser.rs

@@ -553,9 +553,13 @@ impl Parser {
         } else { self.fatal(~"expected type"); };
 
         let sp = mk_sp(lo, self.last_span.hi);
-        return @{id: self.get_id(),
-              node: t,
+        return {
+            let node =
+                self.try_convert_ty_to_obsolete_fixed_length_vstore(sp, t);
+            @{id: self.get_id(),
+              node: node,
               span: sp}
+        };
     }
 
     fn parse_arg_mode() -> mode {
@@ -1061,6 +1065,9 @@ impl Parser {
             ex = expr_lit(@lit);
         }
 
+        let (hi, ex) =
+            self.try_convert_expr_to_obsolete_fixed_length_vstore(lo, hi, ex);
+
         return self.mk_pexpr(lo, hi, ex);
     }
 

src/test/compile-fail/obsolete-syntax.rs

@@ -56,4 +56,15 @@ fn obsolete_with() {
     //~^ ERROR obsolete syntax: with
 }
 
+fn obsolete_fixed_length_vec() {
+    let foo: [int]/1;
+    //~^ ERROR obsolete syntax: fixed-length vector
+    foo = [1]/_;
+    //~^ ERROR obsolete syntax: fixed-length vector
+    let foo: [int]/1;
+    //~^ ERROR obsolete syntax: fixed-length vector
+    foo = [1]/1;
+    //~^ ERROR obsolete syntax: fixed-length vector
+}
+
 fn main() { }