Add cast syntax.

[snipe.git] / type / typechecker.sml

diff --git a/type/typechecker.sml b/type/typechecker.sml
index 06c6d89dce342aafdb9abc4ce88c3196b2573b6b..3191979319b9e292b56ff14d865fc4e806d87585 100644 (file)
--- a/type/typechecker.sml
+++ b/type/typechecker.sml
@@ -24,7 +24,11 @@ struct
       of A.Var a => (case Symbol.look vars a
                      of NONE => (ErrorMsg.error mark ("variable `"^(Symbol.name a)^"' not declared here") ; raise ErrorMsg.Error)
                       | SOME t => t)
+       | A.Cast (ty, e') => if (T.issmall ty) andalso (T.issmall (typeof (tds, funcs) vars mark e'))
+                            then ty
+                            else (ErrorMsg.error mark ("cannot cast: one of `"^(T.Print.pp_type ty)^"' or `"^(T.Print.pp_type (typeof (tds, funcs) vars mark e))^"' was not small"); raise ErrorMsg.Error)
        | A.ConstExp _ => T.Int
+       | A.StringExp _ => T.String
        | A.OpExp (A.EQ, [a, b]) =>
            (case (typeof (tds, funcs) vars mark a, typeof (tds, funcs) vars mark b)
             of (T.Int, T.Int) => T.Int (* You shall pass! *)
@@ -206,7 +210,9 @@ struct
            | SOME UNASSIGNED => ( ErrorMsg.error mark ("usage of unassigned variable `" ^ Symbol.name v ^ "'") ;
                                   raise ErrorMsg.Error )
            | SOME ASSIGNED => ())
+    | varcheck_exp env (A.Cast (ty, e)) mark = varcheck_exp env e mark
     | varcheck_exp env (A.ConstExp _) mark = ()
+    | varcheck_exp env (A.StringExp _) mark = ()
     | varcheck_exp env (A.OpExp (_, l)) mark = List.app (fn znt => varcheck_exp env znt mark) l
     | varcheck_exp env (A.FuncCall (f, l)) mark = List.app (fn znt => varcheck_exp env znt mark) l
     | varcheck_exp env (A.Marked m) mark = varcheck_exp env (Mark.kane m) (Mark.ext m)
@@ -408,6 +414,7 @@ struct
         
   (* XXX does not check big vs. small types *)
   fun typecheck_type (tds, funcs) mark T.Int = ()
+    | typecheck_type (tds, funcs) mark T.String = ()
     | typecheck_type (tds, funcs) mark T.TNull = ()
     | typecheck_type (tds, funcs) mark (T.Pointer t) = typecheck_type (tds, funcs) mark t
     | typecheck_type (tds, funcs) mark (T.Array t) = typecheck_type (tds, funcs) mark t