constant defs

5 files changed, 41 insertions, 3 deletions

diff --git a/bootstrap/all.h b/bootstrap/all.h
index 8c61d5e..5302a07 100644
--- a/bootstrap/all.h
+++ b/bootstrap/all.h
@@ -35,6 +35,7 @@ struct span {
    _(break)              \
    _(case)               \
    _(const)              \
+   _(def)                \
    _(defmacro)           \
    _(do)                 \
    _(else)               \
@@ -229,6 +230,7 @@ enum decltype {
    Dfn,
    Dlet,
    Dstatic,
+   Ddef,
    Dmacro,
    Dtepl,
 };
diff --git a/bootstrap/cgen.c b/bootstrap/cgen.c
index 587f546..3bd6710 100644
--- a/bootstrap/cgen.c
+++ b/bootstrap/cgen.c
@@ -303,7 +303,7 @@ genstmt(struct stmt *stmt) {
          if (decl.externp)
             genstatic(1, decl.name, &decl.var);
          break;
-      case Dtype: case Dmacro: case Dtepl:
+      case Ddef: case Dtype: case Dmacro: case Dtepl:
          break;
       }
       break;
@@ -550,7 +550,7 @@ gendecl(struct decl *decl, bool toplevel) {
    case Dlet:
       assert(!toplevel);
       break;
-   case Dtype: case Dtepl: case Dmacro:
+   case Ddef: case Dtype: case Dtepl: case Dmacro:
       break;
    }
 }
diff --git a/bootstrap/dump.c b/bootstrap/dump.c
index dae457a..047e77b 100644
--- a/bootstrap/dump.c
+++ b/bootstrap/dump.c
@@ -403,6 +403,8 @@ dumpdecl(const struct decl *decl, int ws) {
          epri(" = %e", decl->var.ini);
       epri("\n");
       break;
+   case Ddef:
+      epri("<def> %t = %e", decl->var.ty, decl->var.ini);
    case Dfn:
       epri("<%sfn> (", decl->externp ? "extern " : "");
       for (int i = 0; i < decl->fn.params.n; ++i)
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;
diff --git a/bootstrap/test2.cff b/bootstrap/test2.cff
index 7a61f28..3532f4a 100644
--- a/bootstrap/test2.cff
+++ b/bootstrap/test2.cff
@@ -12,11 +12,15 @@ struct Bit<T> {
    fn neg(x T) T { return ~x; }
 }
 
+def X = 7 + 2,
+   Y = 3.3;
+
 extern fn main() void {
    let n Node<int> = {#null, 0};
    let n Node<int> = {&n, 1};
 
    let x int #?;
+   x = X + 1 + Y;
 
    printf("n %d\n", n.value);
    printf("n link %d\n", n.link.value);