lang: ast: implement caret (return) parsing

lang/ast/expr/arith.c

@@ -813,10 +813,22 @@ struct token_parse_result arith_parse_semicolon(
 	}
 
 	enum ivy_status status = begin_cascade_operation(ctx);
-	
+
 	return PARSE_RESULT(status, 0);
 }
 
+static struct ivy_ast_node *create_return_node(struct ivy_ast_node *val)
+{
+	struct ivy_ast_return_node *ret
+		= (struct ivy_ast_return_node *)ast_node_create(IVY_AST_RETURN);
+	if (!ret) {
+		return NULL;
+	}
+
+	ret->n_val = val;
+	return (struct ivy_ast_node *)ret;
+}
+
 struct token_parse_result expr_finalise(
 	struct ivy_parser *ctx, struct expr_parser_state *state,
 	enum ivy_operator_precedence min_precedence, struct ivy_ast_node **result)
@@ -840,6 +852,10 @@ struct token_parse_result expr_finalise(
 			return PARSE_RESULT(status, 0);
 		}
 
+		if (state->s_return && expr) {
+			expr = create_return_node(expr);
+		}
+
 		*result = expr;
 		return PARSE_RESULT(IVY_OK, PARSE_REPEAT_TOKEN);
 	}
@@ -849,6 +865,11 @@ struct token_parse_result expr_finalise(
 		struct ivy_ast_cascade_node *cascade
 			= expr_finalise_cascade(state);
 
+		if (state->s_return && cascade) {
+			cascade = (struct ivy_ast_cascade_node *)create_return_node(
+				(struct ivy_ast_node *)cascade);
+		}
+
 		*result = (struct ivy_ast_node *)cascade;
 		return PARSE_RESULT(IVY_OK, flags);
 	}
@@ -856,6 +877,12 @@ struct token_parse_result expr_finalise(
 	if (state->s_sub_type == EXPR_SUBTYPE_COMPLEX_MSG) {
 		/* this is the end of a complex message */
 		struct ivy_ast_msg_node *msg = expr_finalise_complex_msg(state);
+
+		if (state->s_return && msg) {
+			msg = (struct ivy_ast_msg_node *)create_return_node(
+				(struct ivy_ast_node *)msg);
+		}
+
 		*result = (struct ivy_ast_node *)msg;
 		return PARSE_RESULT(IVY_OK, 0);
 	}
@@ -863,6 +890,12 @@ struct token_parse_result expr_finalise(
 	if (state->s_sub_type == EXPR_SUBTYPE_KEYWORD_MSG) {
 		/* this is the end of a keyword-message */
 		struct ivy_ast_msg_node *msg = expr_finalise_keyword_msg(state);
+
+		if (state->s_return && msg) {
+			msg = (struct ivy_ast_msg_node *)create_return_node(
+				(struct ivy_ast_node *)msg);
+		}
+
 		*result = (struct ivy_ast_node *)msg;
 		return PARSE_RESULT(IVY_OK, flags);
 	}
@@ -874,6 +907,10 @@ struct token_parse_result expr_finalise(
 		return PARSE_RESULT(status, 0);
 	}
 
+	if (expr && state->s_return) {
+		expr = create_return_node(expr);
+	}
+
 	*result = expr;
 	return PARSE_RESULT(IVY_OK, flags);
 }

lang/ast/expr/expr.c

@@ -33,6 +33,7 @@ struct ast_node_type expr_node_ops = {
 		SYM_PARSER(RIGHT_PAREN, arith_parse_right_paren),
 		SYM_PARSER(SEMICOLON, arith_parse_semicolon),
 		SYM_PARSER(UNDERSCORE, arith_parse_operand),
+		SYM_PARSER(CARET, arith_parse_caret),
 		SYM_PARSER(COMMA, arith_parse_comma),
 		SYM_PARSER(DOT, arith_parse_dot),
 		SYM_PARSER(EQUAL_RIGHT_ANGLE, arith_parse_equal_right_angle),

lang/ast/expr/expr.h

@@ -47,6 +47,9 @@ struct expr_parser_state {
 	enum expr_type s_type;
 	enum expr_subtype s_sub_type;
 
+	/* this is a return statement (prefixed with a caret) */
+	bool s_return;
+
 	/* for arithmetic expressions, this records whether the previous
 	 * component (either a token or parenthesised group of tokens) is an
 	 * operator, operand, or message */
@@ -117,6 +120,8 @@ extern struct token_parse_result arith_parse_semicolon(
 	struct ivy_parser *ctx, struct ivy_token *tok);
 extern struct token_parse_result arith_parse_dot(
 	struct ivy_parser *ctx, struct ivy_token *tok);
+extern struct token_parse_result arith_parse_caret(
+	struct ivy_parser *ctx, struct ivy_token *tok);
 extern struct token_parse_result arith_parse_comma(
 	struct ivy_parser *ctx, struct ivy_token *tok);
 extern struct token_parse_result arith_parse_equal_right_angle(

lang/ast/node.c

@@ -24,6 +24,7 @@ extern struct ast_node_type cond_group_node_ops;
 extern struct ast_node_type cond_node_ops;
 extern struct ast_node_type match_node_ops;
 extern struct ast_node_type while_loop_node_ops;
+extern struct ast_node_type return_node_ops;
 extern struct ast_node_type discard_node_ops;
 
 static const struct ast_node_type *node_ops[] = {
@@ -46,6 +47,7 @@ static const struct ast_node_type *node_ops[] = {
 	[IVY_AST_COND] = &cond_node_ops,
 	[IVY_AST_MATCH] = &match_node_ops,
 	[IVY_AST_WHILE_LOOP] = &while_loop_node_ops,
+	[IVY_AST_RETURN] = &return_node_ops,
 	[IVY_AST_DISCARD] = &discard_node_ops,
 };
 static const size_t nr_node_ops = sizeof node_ops / sizeof node_ops[0];
@@ -243,6 +245,7 @@ const char *ivy_ast_node_type_to_string(enum ivy_ast_node_type v)
 		ENUM_STR(IVY_AST_COND);
 		ENUM_STR(IVY_AST_TUPLE);
 		ENUM_STR(IVY_AST_BLOCK);
+		ENUM_STR(IVY_AST_RETURN);
 		ENUM_STR(IVY_AST_TYPE_COUNT);
 	default:
 		return "";

lang/ast/return.c

@@ -0,0 +1,19 @@
+#include "ctx.h"
+#include "iterate.h"
+#include "node.h"
+
+static void collect_children(
+	struct ivy_ast_node *node, struct ivy_ast_node_iterator *iterator)
+{
+	struct ivy_ast_return_node *ret = (struct ivy_ast_return_node *)node;
+
+	if (ret->n_val) {
+		ast_node_iterator_enqueue_node(iterator, node, ret->n_val);
+	}
+}
+
+struct ast_node_type return_node_ops = {
+	.n_collect_children = collect_children,
+	.n_state_size = sizeof(struct parser_state),
+	.n_node_size = sizeof(struct ivy_ast_return_node),
+};

lang/include/ivy/lang/ast.h

@@ -14,6 +14,7 @@ enum ivy_ast_node_type {
 	IVY_AST_NONE = 0x00,
 	IVY_AST_UNIT,
 	IVY_AST_OP,
+	IVY_AST_RETURN,
 	IVY_AST_MSG,
 	IVY_AST_CLASS,
 	IVY_AST_MSGH,
@@ -71,6 +72,11 @@ struct ivy_ast_op_node {
 	struct ivy_ast_node *n_right;
 };
 
+struct ivy_ast_return_node {
+	struct ivy_ast_node n_base;
+	struct ivy_ast_node *n_val;
+};
+
 struct ivy_ast_selector_node {
 	struct ivy_ast_node n_base;
 	enum ivy_selector_recipient n_recipient;