constant defs

1 files changed, 31 insertions, 1 deletions

diff --git a/bootstrap/parse.c b/bootstrap/parse.c
index 912a346..7b2e007 100644
--- a/bootstrap/parse.c
+++ b/bootstrap/parse.c
@@ -1055,6 +1055,8 @@ pexprimary(struct parser *P) {
             ex.ty = decl->var.ty;
          } else if (decl->t == Dstatic) {
             ex.ty = decl->var.ty;
+         } else if (decl->t == Ddef) {
+            ex = *decl->var.ini;
          } else if (decl->t == Dfn) {
             if (!decl->fn.selfty)
                ((struct decl *)decl)->fn.selfty = fntype(&decl->fn);
@@ -1934,7 +1936,7 @@ isdecltokt(int tokt) {
    switch (tokt)
    case TKkw_extern: case TKkw_fn: case TKkw_typedef:
    case TKkw_defmacro: case TKkw_static: case TKkw_enum:
-   case TKkw_struct: case TKkw_union:
+   case TKkw_struct: case TKkw_union: case TKkw_def:
       return 1;
    return 0;
 }
@@ -2617,6 +2619,28 @@ staticvaryield(struct decl *decl, void *arg) {
       a->yield(decl, a->yarg);
 }
 
+struct defyarg {
+   struct parser *P;
+   struct span espan;
+   decl_yielder_t yield;
+   void *yarg;
+};
+
+static void
+defyield(struct decl *decl, void *arg) {
+   struct defyarg *a = arg;
+   decl->t = Ddef;
+   decl->span = a->espan;
+   assert(decl->name);
+   if (!decl->var.ini)
+      fatal(a->P, decl->span, "def must have a value");
+   if (!fold(decl->var.ini))
+      fatal(a->P, decl->var.ini->span, "def initializer must be constant expression");
+   putdecl(a->P, decl->span, decl);
+   if (a->yield)
+      a->yield(decl, a->yarg);
+}
+
 static void
 parsedecl(decl_yielder_t yield, void *yarg, struct parser *P, bool toplevel) {
    struct tok tok = { .span = P->tokspan };
@@ -2646,6 +2670,12 @@ parsedecl(decl_yielder_t yield, void *yarg, struct parser *P, bool toplevel) {
             P, externp, toplevel, tok.span, yield, yarg
       }, P, 0, externp);
       return;
+   } else if (lexmatch(P, &tok, TKkw_def)) {
+      if (externp) fatal(P, tok.span, "def cannot be `extern'");
+      parsevardecl(defyield, &(struct defyarg) {
+            P, tok.span, yield, yarg
+      }, P, 0, 0);
+      return;
    } else if (lexmatch(P, &tok, TKkw_typedef)) {
       if (externp) fatal(P, tok.span, "typedef cannot be `extern'");
       decl.t = Dtype;