lang: replace stack-based parser with a recursive parser

lang/parse/for.c

@@ -0,0 +1,67 @@
+#include "ctx.h"
+
+#include <ivy/lang/ast.h>
+
+bool parse_for(struct ivy_parser *parser, struct ivy_ast_node **out)
+{
+	if (!parse_keyword(parser, IVY_KW_FOR)) {
+		parse_trace(parser, "expected `for` keyword");
+		return false;
+	}
+
+	struct ivy_ast_for_loop_node *for_node = create_node(IVY_AST_FOR_LOOP);
+
+	if (!parse_expr(parser, EXPR_PARSE_STOP_KW_IN, &for_node->n_iterator)) {
+		parse_trace(parser, "invalid for-loop iterator");
+		return false;
+	}
+
+	if (!parse_keyword(parser, IVY_KW_IN)) {
+		parse_trace(parser, "expected `in` after for-loop iterator");
+		return false;
+	}
+
+	if (!parse_expr(parser, EXPR_PARSE_STOP_LEFT_BRACKET, &for_node->n_iterable)) {
+		parse_trace(parser, "invalid for-loop iterable");
+		return false;
+	}
+
+	if (!parse_block(parser, &for_node->n_body)) {
+		parse_trace(parser, "invalid for-loop body");
+		return false;
+	}
+
+	*out = generic_node(for_node);
+	return true;
+}
+
+bool parse_for_inline(
+	struct ivy_parser *parser, struct ivy_ast_node *body,
+	struct ivy_ast_node **out)
+{
+	if (!parse_keyword(parser, IVY_KW_FOR)) {
+		parse_trace(parser, "expected `for` keyword");
+		return false;
+	}
+
+	struct ivy_ast_for_loop_node *for_node = create_node(IVY_AST_FOR_LOOP);
+	for_node->n_body = body;
+
+	if (!parse_expr(parser, EXPR_PARSE_STOP_KW_IN, &for_node->n_iterator)) {
+		parse_trace(parser, "invalid for-loop iterator");
+		return false;
+	}
+
+	if (!parse_keyword(parser, IVY_KW_IN)) {
+		parse_trace(parser, "expected `in` after for-loop iterator");
+		return false;
+	}
+
+	if (!parse_expr(parser, EXPR_PARSE_NORMAL, &for_node->n_iterable)) {
+		parse_trace(parser, "invalid for-loop iterable");
+		return false;
+	}
+
+	*out = generic_node(for_node);
+	return true;
+}