From 9952500a2786720dcdd4be96ff5a945c4d423ffb Mon Sep 17 00:00:00 2001
From: Leo Tenenbaum <pommicket@gmail.com>
Date: Fri, 10 Jan 2020 10:30:21 -0500
Subject: allow circular dependencies in structs

---
 cgen.c   |  4 +---
 eval.c   | 12 ++++++++++--
 main.c   |  2 ++
 parse.c  | 16 +++++++++-------
 test.toc | 10 +++++++++-
 types.c  |  6 ++++++
 6 files changed, 37 insertions(+), 13 deletions(-)

diff --git a/cgen.c b/cgen.c
index 9f16b8b..2131abd 100644
--- a/cgen.c
+++ b/cgen.c
@@ -158,9 +158,7 @@ static bool cgen_defs_decl(CGenerator *g, Declaration *d);
 #define cgen_recurse_subtypes(f, g, type, extra)	\
 	switch (type->kind) {							\
 	case TYPE_STRUCT:								\
-		arr_foreach(type->struc->fields, Field, fl)	\
-			if (!f(g, fl->type, extra))				\
-				return false;						\
+		/* don't descend into fields */				\
 		break;										\
 	case TYPE_FN:									\
 		arr_foreach(type->fn.types, Type, sub) {	\
diff --git a/eval.c b/eval.c
index 38fc316..e13c5ba 100644
--- a/eval.c
+++ b/eval.c
@@ -1320,8 +1320,16 @@ static bool eval_expr(Evaluator *ev, Expression *e, Value *v) {
 		Declaration *d = NULL;
 		if (is_decl) {
 			d = idecl->decl;
-			if (!types_decl(ev->typer, d)) return false;
-			assert(d->type.flags & TYPE_IS_RESOLVED);
+			if ((d->flags & DECL_HAS_EXPR) && d->expr.kind == EXPR_TYPE && d->expr.typeval.kind == TYPE_STRUCT) {
+				v->type = allocr_malloc(ev->allocr, sizeof *v->type);
+				v->type->flags = TYPE_IS_RESOLVED;
+				v->type->kind = TYPE_STRUCT;
+				v->type->struc = d->expr.typeval.struc;
+				break;
+			} else {
+				if (!types_decl(ev->typer, d)) return false;
+				assert(d->type.flags & TYPE_IS_RESOLVED);
+			}
 		}
 		if (idecl->flags & IDECL_HAS_VAL) {
 			*v = idecl->val;
diff --git a/main.c b/main.c
index 0259f07..c329d27 100644
--- a/main.c
+++ b/main.c
@@ -18,6 +18,8 @@
 
 /* 
 TODO:
+check for problematic circular dependencies
+test really long type names
 packages
 ---
 X ::= newtype(int); or something
diff --git a/parse.c b/parse.c
index bb3bf5e..3265f7d 100644
--- a/parse.c
+++ b/parse.c
@@ -228,13 +228,15 @@ static size_t type_to_str_(Type *t, char *buffer, size_t bufsize) {
 		return written;
 	}
 	case TYPE_STRUCT: {
-		size_t written = str_copy(buffer, bufsize, "struct { ");
-		arr_foreach(t->struc->fields, Field, f) {
-			written += type_to_str_(f->type, buffer + written, bufsize - written);
-			written += str_copy(buffer + written, bufsize - written, "; ");
-		}
-		written += str_copy(buffer + written, bufsize - written, " }");
-		return written;
+		/* size_t written = str_copy(buffer, bufsize, "struct { "); */
+		/* arr_foreach(t->struc->fields, Field, f) { */
+			/* written += type_to_str_(f->type, buffer + written, bufsize - written); */
+			/* written += str_copy(buffer + written, bufsize - written, "; "); */
+		/* } */
+		/* written += str_copy(buffer + written, bufsize - written, " }"); */
+		/* TODO: show name or something (to allow circular dependencies)? */
+		return str_copy(buffer, bufsize, "struct { ... }");
+		
 	}
 	case TYPE_ARR: {
 		size_t written = str_copy(buffer, bufsize, "[");
diff --git a/test.toc b/test.toc
index fc5dd32..2855bb1 100644
--- a/test.toc
+++ b/test.toc
@@ -6,7 +6,15 @@ putf ::= fn(x: float) {
 	 #C("printf(\"%f\\n\", (double)x);
 ");
 };
-point ::= pkg "point";
+// point ::= pkg "point";
+
+Foo ::= struct {
+	b: &Bar;
+};
+
+Bar ::= struct {
+	f: &Foo;
+};
 
 main ::= fn() {
 f::=fn(t::Type)Type {t};
diff --git a/types.c b/types.c
index e2a544c..2de05c0 100644
--- a/types.c
+++ b/types.c
@@ -441,6 +441,12 @@ static bool type_of_ident(Typer *tr, Location where, Identifier i, Type *t) {
 				/* allow using a function before declaring it */
 				if (!type_of_fn(tr, d->expr.fn, t, 0)) return false;
 				return true;
+			} else if ((d->flags & DECL_HAS_EXPR) && (d->expr.kind == EXPR_TYPE)) {
+				/* allow using a type before declaring it */
+				t->kind = TYPE_BUILTIN;
+				t->builtin = BUILTIN_TYPE;
+				t->flags = TYPE_IS_RESOLVED;
+				return true;
 			} else {
 				if (where.start <= d->where.end) {
 					char *s = ident_to_str(i);
-- 
cgit v1.2.3