From 312e737f9fcccf933633d2d9d569051eea4990cd Mon Sep 17 00:00:00 2001
From: Max Wash <mbswash@gmail.com>
Date: Mon, 8 Sep 2025 16:21:05 +0100
Subject: [PATCH] lang: codegen: implement returning the last value evaluated
 in a block

---
 lang/codegen/block.c | 74 +++++++++++++++++++++++++++++++++++++-------
 1 file changed, 63 insertions(+), 11 deletions(-)

diff --git a/lang/codegen/block.c b/lang/codegen/block.c
index a9af1e3..bad4349 100644
--- a/lang/codegen/block.c
+++ b/lang/codegen/block.c
@@ -8,6 +8,9 @@ struct block_codegen_state {
 	struct code_generator_state s_base;
 	struct code_generator_scope *s_scope;
 	struct codegen_var_map s_vars;
+
+	/* the value of the final expression in the block */
+	struct mie_value *s_result;
 };
 
 static struct code_generator_result gen_expr(
@@ -23,21 +26,21 @@ static struct code_generator_result gen_expr(
 	return CODEGEN_RESULT_OK(CODEGEN_R_REPEAT_NODE);
 }
 
-static struct code_generator_result gen_var_declaration(
+static struct code_generator_result gen_for_loop(
 	struct ivy_codegen *gen, struct code_generator_state *state,
 	struct ivy_ast_node *node, size_t depth)
 {
-	struct block_codegen_state *block = (struct block_codegen_state *)state;
-	struct mie_builder *builder = gen->c_builder;
-	struct mie_func *current = mie_builder_get_current_func(builder);
+	codegen_push_generator(
+		gen, CODE_GENERATOR_FOR_LOOP, CODEGEN_F_IGNORE_RESULT, NULL);
+	return CODEGEN_RESULT_OK(CODEGEN_R_REPEAT_NODE);
+}
 
-	enum ivy_status status = IVY_OK;
-
-	if (status != IVY_OK) {
-		return CODEGEN_RESULT_ERR(status);
-	}
-
-	codegen_push_generator(gen, CODE_GENERATOR_VAR, 0, NULL);
+static struct code_generator_result gen_while_loop(
+	struct ivy_codegen *gen, struct code_generator_state *state,
+	struct ivy_ast_node *node, size_t depth)
+{
+	codegen_push_generator(
+		gen, CODE_GENERATOR_WHILE_LOOP, CODEGEN_F_IGNORE_RESULT, NULL);
 	return CODEGEN_RESULT_OK(CODEGEN_R_REPEAT_NODE);
 }
 
@@ -59,6 +62,38 @@ static struct code_generator_result gen_return(
 	return CODEGEN_RESULT_OK(CODEGEN_R_REPEAT_NODE);
 }
 
+static struct code_generator_result gen_loop_break(
+	struct ivy_codegen *gen, struct code_generator_state *state,
+	struct ivy_ast_node *node, size_t depth)
+{
+	struct block_codegen_state *block = (struct block_codegen_state *)state;
+
+	if (!state->s_loop_break_target) {
+		return CODEGEN_RESULT_ERR(IVY_ERR_BAD_SYNTAX);
+	}
+
+	mie_builder_br(gen->c_builder, state->s_loop_break_target);
+
+	block->s_result = mie_ctx_get_null(gen->c_ctx);
+	return CODEGEN_RESULT_OK(0);
+}
+
+static struct code_generator_result gen_loop_repeat(
+	struct ivy_codegen *gen, struct code_generator_state *state,
+	struct ivy_ast_node *node, size_t depth)
+{
+	struct block_codegen_state *block = (struct block_codegen_state *)state;
+
+	if (!state->s_loop_repeat_target) {
+		return CODEGEN_RESULT_ERR(IVY_ERR_BAD_SYNTAX);
+	}
+
+	mie_builder_br(gen->c_builder, state->s_loop_repeat_target);
+
+	block->s_result = mie_ctx_get_null(gen->c_ctx);
+	return CODEGEN_RESULT_OK(0);
+}
+
 static enum ivy_status state_init(
 	struct ivy_codegen *gen, struct code_generator_state *state,
 	uintptr_t argv, void *argp)
@@ -73,9 +108,21 @@ static enum ivy_status state_fini(
 	struct ivy_codegen *gen, struct code_generator_state *state,
 	struct code_generator_value *result)
 {
+	struct block_codegen_state *block = (struct block_codegen_state *)state;
+	code_generator_value_set_mie_value(result, block->s_result);
+	codegen_var_map_fini(&block->s_vars);
 	return IVY_OK;
 }
 
+static struct code_generator_result value_received(
+	struct ivy_codegen *gen, struct code_generator_state *state,
+	struct code_generator_value *value)
+{
+	struct block_codegen_state *block = (struct block_codegen_state *)state;
+	block->s_result = code_generator_value_get_mie_value(value);
+	return CODEGEN_RESULT_OK(0);
+}
+
 static enum ivy_status define_var(
 	struct ivy_codegen *gen, struct code_generator_state *state,
 	const char *ident, const struct codegen_var *var)
@@ -106,8 +153,13 @@ struct code_generator block_generator = {
 	.g_state_size = sizeof(struct block_codegen_state),
 	.g_state_init = state_init,
 	.g_state_fini = state_fini,
+	.g_value_received = value_received,
 	.g_node_generators = {
+		NODE_CODEGEN(FOR_LOOP, gen_for_loop),
+		NODE_CODEGEN(WHILE_LOOP, gen_while_loop),
 		NODE_CODEGEN(RETURN, gen_return),
+		NODE_CODEGEN(LOOP_BREAK, gen_loop_break),
+		NODE_CODEGEN(LOOP_REPEAT, gen_loop_repeat),
 	},
 	.g_expr_generator = gen_expr,
 	.g_define_var = define_var,