cleanup. [skip CI]

Source/3rdParty/yuescript/parser.cpp

@@ -15,15 +15,9 @@ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 #include <stdexcept>
 #include <unordered_map>
 #include <unordered_set>
-#include <memory>
 
 #include "yuescript/parser.hpp"
 
-#define _DEFER(code, line) std::shared_ptr<void> _defer_##line(nullptr, [&](auto) { \
-	code; \
-})
-#define DEFER(code) _DEFER(code, __LINE__)
-
 namespace parserlib {
 
 // internal private class that manages access to the public classes' internals.
@@ -914,7 +908,7 @@ bool _context::parse_non_term(rule& r) {
 	// save the state of the rule
 	rule::_state old_state = r.m_state;
 	// restore the rule's state
-	DEFER(r.m_state = old_state);
+	rule::_state_guard quard(old_state, &r.m_state);
 
 	// success/failure result
 	bool ok = false;
@@ -1008,7 +1002,7 @@ bool _context::parse_term(rule& r) {
 	// save the state of the rule
 	rule::_state old_state = r.m_state;
 	// restore the rule's state
-	DEFER(r.m_state = old_state);
+	rule::_state_guard quard(old_state, &r.m_state);
 
 	// success/failure result
 	bool ok = false;

Source/3rdParty/yuescript/parser.hpp

@@ -294,6 +294,17 @@ class rule {
 			, m_mode(mode) { }
 	};
 
+	struct _state_guard {
+		_state m_old_state;
+		_state* m_current_state;
+		_state_guard(const _state& old, _state* new_)
+			: m_old_state(old)
+			, m_current_state(new_) { }
+		~_state_guard() {
+			*m_current_state = m_old_state;
+		}
+	};
+
 	// internal expression
 	_expr* m_expr;