lang: replace stack-based parser with a recursive parser

lang/parse/while.c

@@ -0,0 +1,49 @@
+#include "ctx.h"
+
+#include <ivy/lang/ast.h>
+
+bool parse_while(struct ivy_parser *parser, struct ivy_ast_node **out)
+{
+	if (!parse_keyword(parser, IVY_KW_WHILE)) {
+		parse_trace(parser, "expected `while` keyword");
+		return false;
+	}
+
+	struct ivy_ast_while_loop_node *while_node
+		= create_node(IVY_AST_WHILE_LOOP);
+
+	if (!parse_expr(parser, EXPR_PARSE_STOP_LEFT_BRACKET, &while_node->n_cond)) {
+		parse_trace(parser, "invalid while condition");
+		return false;
+	}
+
+	if (!parse_block(parser, &while_node->n_body)) {
+		parse_trace(parser, "invalid while body");
+		return false;
+	}
+
+	*out = generic_node(while_node);
+	return true;
+}
+
+bool parse_while_inline(
+	struct ivy_parser *parser, struct ivy_ast_node *body,
+	struct ivy_ast_node **out)
+{
+	if (!parse_keyword(parser, IVY_KW_WHILE)) {
+		parse_trace(parser, "expected `while` keyword");
+		return false;
+	}
+
+	struct ivy_ast_while_loop_node *while_node
+		= create_node(IVY_AST_WHILE_LOOP);
+	while_node->n_body = body;
+
+	if (!parse_expr(parser, EXPR_PARSE_NORMAL, &while_node->n_cond)) {
+		parse_trace(parser, "invalid while condition");
+		return false;
+	}
+
+	*out = generic_node(while_node);
+	return true;
+}