diff --git a/src/snc/expr.h b/src/snc/expr.h
index 9ff21050c8ae4bf43eea268b8d07fd9d5e97b3b1..67431a2a811f2fbd8d2e41e61e54257d080e3803 100644
--- a/src/snc/expr.h
+++ b/src/snc/expr.h
@@ -46,5 +46,6 @@ Expr *decl_create(Token name);
Expr *decl_postfix_array(Expr *d, char *s);
Expr *decl_postfix_function(Expr *d, Expr *args);
Expr *decl_prefix_pointer(Expr *d);
+Expr *decl_prefix_const(Expr *d);
#endif /*INCLparseh*/
diff --git a/src/snc/snl.lem b/src/snc/snl.lem
index 7e017f307f293308d718d9a617190fcb2278ee9c..f61b7887efb473fcc18c0a6d2d3b3343f4fc65b8 100644
--- a/src/snc/snl.lem
+++ b/src/snc/snl.lem
@@ -194,6 +194,7 @@ declarator(p) ::= declarator(x)
LPAREN param_decls(ps) RPAREN. [POST] { p = decl_postfix_function(x, ps); }
declarator(p) ::= LPAREN declarator(x) RPAREN. [PRE] { p = x; }
declarator(p) ::= ASTERISK declarator(x). [PRE] { p = decl_prefix_pointer(x); }
+declarator(p) ::= CONST declarator(x). [PRE] { p = decl_prefix_const(x); }
param_decls(p) ::= param_decl(x). { p = x; }
param_decls(p) ::= param_decls(xs) COMMA param_decl(x). { p = link_expr(xs, x); }
@@ -257,6 +258,8 @@ type_expr(p) ::= basetype(t) abs_decl(d). { p = decl_add_base_type(d, t); }
abs_decl(p) ::= LPAREN abs_decl(x) RPAREN. { p = x; }
abs_decl(p) ::= ASTERISK. [PRE] { p = decl_prefix_pointer(abs_decl_create()); }
abs_decl(p) ::= ASTERISK abs_decl(d). [PRE] { p = decl_prefix_pointer(d); }
+abs_decl(p) ::= CONST. [PRE] { p = decl_prefix_const(abs_decl_create()); }
+abs_decl(p) ::= CONST abs_decl(d). [PRE] { p = decl_prefix_const(d); }
abs_decl(p) ::= subscript(s). [POST] { p = decl_postfix_array(abs_decl_create(), s.str); }
abs_decl(p) ::= abs_decl(d) subscript(s). [POST]{ p = decl_postfix_array(d, s.str); }
abs_decl(p) ::= LPAREN param_decls(ps) RPAREN. [POST]
diff --git a/src/snc/snl.re b/src/snc/snl.re
index 267b7d9505f84dca5c490fa756cccabc1329dae0..3d514522b19845afd23f31080ea9031124f73d32 100644
--- a/src/snc/snl.re
+++ b/src/snc/snl.re
@@ -234,6 +234,7 @@ snl:
"break" { KEYWORD(BREAK, "break"); }
"char" { TYPEWORD(CHAR, "char"); }
"connect" { KEYWORD(CONNECT, "connect"); }
+ "const" { TYPEWORD(CONST, "const"); }
"continue" { KEYWORD(CONTINUE, "continue"); }
"double" { TYPEWORD(DOUBLE, "double"); }
"else" { KEYWORD(ELSE, "else"); }
diff --git a/src/snc/var_types.c b/src/snc/var_types.c
index 3c2cb6e1754a16d9b2b86b13c679803a6f96b815..e22e6839014e0627c3f7a28fbb414d02918787f8 100644
--- a/src/snc/var_types.c
+++ b/src/snc/var_types.c
@@ -64,6 +64,33 @@ Expr *decl_add_base_type(Expr *ds, Type basetype)
}
t->parent->val.function.return_type = t;
break;
+ case T_CONST:
+ switch (t->tag) {
+ case T_NONE:
+ error_at_expr(d, "cannot declare constant foreign entity\n");
+ break;
+ case T_EVFLAG:
+ error_at_expr(d, "cannot declare constant event flag\n");
+ break;
+ case T_VOID:
+ error_at_expr(d, "cannot declare constant void\n");
+ break;
+ case T_ARRAY:
+ error_at_expr(d, "cannot declare constant array\n");
+ break;
+ case T_FUNCTION:
+ warning_at_expr(d, "declaring constant function is redundant\n");
+ break;
+ case T_CONST:
+ warning_at_expr(d, "declaring constant constant is redundant\n");
+ break;
+ case T_PRIM:
+ case T_FOREIGN:
+ case T_POINTER:
+ break;
+ }
+ t->parent->val.constant.value_type = t;
+ break;
default:
assert(impossible);
}
@@ -163,6 +190,19 @@ Expr *decl_prefix_pointer(Expr *d)
return d;
}
+Expr *decl_prefix_const(Expr *d)
+{
+ Type *t = new(Type);
+
+#ifdef DEBUG
+ report("decl_prefix_const\n");
+#endif
+ assert(d->type == D_DECL); /* pre-condition */
+ t->tag = T_CONST;
+ t->parent = d->extra.e_decl->type;
+ d->extra.e_decl->type = t;
+ return d;
+}
Type mk_prim_type(enum prim_type_tag tag)
{
@@ -248,6 +288,7 @@ static unsigned type_assignable_array(Type *t, int depth)
case T_FUNCTION:
case T_EVFLAG:
case T_VOID:
+ case T_CONST:
return FALSE;
case T_ARRAY:
return type_assignable_array(t->val.array.elem_type, depth + 1);
@@ -278,6 +319,16 @@ static void gen_array_pointer(Type *t, enum type_tag last_tag, const char *prefi
if (paren)
gen_code(")");
break;
+ case T_CONST:
+ if (paren)
+ gen_code("(");
+ else
+ gen_code(" ");
+ gen_code("const");
+ gen_array_pointer(t->parent, t->tag, prefix, name);
+ if (paren)
+ gen_code(")");
+ break;
case T_ARRAY:
gen_array_pointer(t->parent, t->tag, prefix, name);
gen_code("[%d]", t->val.array.num_elems);
diff --git a/src/snc/var_types.h b/src/snc/var_types.h
index ba48b05f7662feb6f43bfbfacc14260d68e37812..2194fbeca11ce3bcb76a01426f25630071e6e62e 100644
--- a/src/snc/var_types.h
+++ b/src/snc/var_types.h
@@ -18,6 +18,7 @@ enum type_tag {
T_POINTER,
T_ARRAY,
T_FUNCTION,
+ T_CONST,
};
enum foreign_type_tag {
@@ -36,6 +37,10 @@ struct pointer_type {
struct type *value_type;
};
+struct constant_type {
+ struct type *value_type;
+};
+
struct function_type {
struct expression *param_decls;
struct type *return_type;
@@ -56,6 +61,7 @@ struct type {
struct pointer_type pointer;
struct array_type array;
struct function_type function;
+ struct constant_type constant;
} val;
struct type *parent;
};
diff --git a/test/compiler/type_expr.st b/test/compiler/type_expr.st
index fa2415b06c80afccf1a53a15d2a80e4b6e29e708..7f95c815a05ae8eb27cce17344a82928bf1a2531 100644
--- a/test/compiler/type_expr.st
+++ b/test/compiler/type_expr.st
@@ -33,6 +33,9 @@ entry {
void (*pf4)(int**) = (void (*)(int**))n;
void (*pf5)(double**,int) = (void (*)(double**,int))n;
void (*pf6)(double**,int(**)[2]) = (void (*)(double**,int(**)[2]))n;
+ int const c = (int const)n;
+ int const *pc = (int const *)n;
+ unsigned long *const cp = (unsigned long *const)n;
double **pd = (double**)(int*)n;
double **ppd = (double**)(int(*)[3])n;
void (*lf)(
@@ -44,6 +47,9 @@ entry {
void (*pf4)(int**),
void (*pf5)(double**,int),
void (*pf6)(double**,int(**)[2]),
+ int const c,
+ int const *pc,
+ unsigned long *const cp,
double **pd,
double **ppd
) = (void (*)(
@@ -55,10 +61,13 @@ entry {
void (*pf4)(int**),
void (*pf5)(double**,int),
void (*pf6)(double**,int(**)[2]),
+ int const c,
+ int const *pc,
+ unsigned long *const cp,
double **pd,
double **ppd
))n;
- lf(p,pp,pf1,pf2,pf3,pf4,pf5,pf6,pd,ppd);
+ lf(p,pp,pf1,pf2,pf3,pf4,pf5,pf6,c,pc,cp,pd,ppd);
}
#include "../simple.st"