Support corecursive structs

compile.c

@@ -2160,6 +2160,9 @@ module_code_t compile_file(ast_t *ast)
     env->file_prefix = heap_strf("%s$", name);
     Table$str_set(env->imports, name, env);
 
+    for (ast_list_t *stmt = Match(ast, Block)->statements; stmt; stmt = stmt->next) {
+        prebind_statement(env, stmt->ast);
+    }
     for (ast_list_t *stmt = Match(ast, Block)->statements; stmt; stmt = stmt->next) {
         // Hack: make sure global is bound as foo$var:
         if (stmt->ast->tag == Declare && Match(Match(stmt->ast, Declare)->var, Var)->name[0] != '_')

test/structs.tm

@@ -4,6 +4,9 @@ struct Mixed(x:Int, text:Text)
 struct LinkedList(x:Int, next=!@LinkedList)
 struct Password(text:Text; secret)
 
+struct CorecursiveA(other:@CorecursiveB?)
+struct CorecursiveB(other=!@CorecursiveA)
+
 func test_literals():
 	>> x := Pair(10, 20)
 	= Pair(x=10, y=20)
@@ -63,3 +66,5 @@ func main():
 	>> users_by_password[my_pass]
 	= "User1"
 
+	>> CorecursiveA(@CorecursiveB())
+

typecheck.c

@@ -126,6 +126,9 @@ static env_t *load_module(env_t *env, ast_t *use_ast)
     ast_t *ast = parse_file(f, NULL);
     if (!ast) errx(1, "Could not compile!");
 
+    for (ast_list_t *stmt = Match(ast, Block)->statements; stmt; stmt = stmt->next) {
+        prebind_statement(module_env, stmt->ast);
+    }
     for (ast_list_t *stmt = Match(ast, Block)->statements; stmt; stmt = stmt->next) {
         bind_statement(module_env, stmt->ast);
     }
@@ -133,6 +136,55 @@ static env_t *load_module(env_t *env, ast_t *use_ast)
     return module_env;
 }
 
+void prebind_statement(env_t *env, ast_t *statement)
+{
+    switch (statement->tag) {
+    case DocTest: {
+        prebind_statement(env, Match(statement, DocTest)->expr);
+        break;
+    }
+    case StructDef: {
+        auto def = Match(statement, StructDef);
+        if (get_binding(env, def->name))
+            code_err(statement, "A %T called '%s' has already been defined", get_binding(env, def->name)->type, def->name);
+
+        env_t *ns_env = namespace_env(env, def->name);
+        type_t *type = Type(StructType, .name=def->name, .opaque=true, .env=ns_env); // placeholder
+        Table$str_set(env->types, def->name, type);
+        for (ast_list_t *stmt = def->namespace ? Match(def->namespace, Block)->statements : NULL; stmt; stmt = stmt->next) {
+            prebind_statement(ns_env, stmt->ast);
+        }
+        break;
+    }
+    case EnumDef: {
+        auto def = Match(statement, EnumDef);
+        if (get_binding(env, def->name))
+            code_err(statement, "A %T called '%s' has already been defined", get_binding(env, def->name)->type, def->name);
+
+        env_t *ns_env = namespace_env(env, def->name);
+        type_t *type = Type(EnumType, .name=def->name, .opaque=true, .env=ns_env); // placeholder
+        Table$str_set(env->types, def->name, type);
+        for (ast_list_t *stmt = def->namespace ? Match(def->namespace, Block)->statements : NULL; stmt; stmt = stmt->next) {
+            prebind_statement(ns_env, stmt->ast);
+        }
+        break;
+    }
+    case LangDef: {
+        auto def = Match(statement, LangDef);
+        if (get_binding(env, def->name))
+            code_err(statement, "A %T called '%s' has already been defined", get_binding(env, def->name)->type, def->name);
+
+        env_t *ns_env = namespace_env(env, def->name);
+        type_t *type = Type(TextType, .lang=def->name, .env=ns_env);
+        Table$str_set(env->types, def->name, type);
+        for (ast_list_t *stmt = def->namespace ? Match(def->namespace, Block)->statements : NULL; stmt; stmt = stmt->next)
+            prebind_statement(ns_env, stmt->ast);
+        break;
+    }
+    default: break;
+    }
+}
+
 void bind_statement(env_t *env, ast_t *statement)
 {
     switch (statement->tag) {

typecheck.h

@@ -13,6 +13,7 @@
 
 type_t *parse_type_ast(env_t *env, type_ast_t *ast);
 type_t *get_type(env_t *env, ast_t *ast);
+void prebind_statement(env_t *env, ast_t *statement);
 void bind_statement(env_t *env, ast_t *statement);
 type_t *get_math_type(env_t *env, ast_t *ast, type_t *lhs_t, type_t *rhs_t);
 bool is_discardable(env_t *env, ast_t *ast);