Add ??? operator

Author: passcod

Zend/zend_ast.c

@@ -573,6 +573,7 @@ ZEND_API void zend_ast_apply(zend_ast *ast, zend_ast_apply_func fn) {
  *   90     right           = += -= *= /= .= %= &= |= ^= <<= >>= **=
  *  100     left            ? :
  *  110     right           ??
+ *  115     right           ???
  *  120     left            ||
  *  130     left            &&
  *  140     left            |
@@ -1426,6 +1427,7 @@ static void zend_ast_export_ex(smart_str *str, zend_ast *ast, int priority, int
 		case ZEND_AST_YIELD_FROM:
 			PREFIX_OP("yield from ", 85, 86);
 		case ZEND_AST_COALESCE: BINARY_OP(" ?? ", 110, 111, 110);
+		case ZEND_AST_EXCEPTION_COALESCE: BINARY_OP(" ??? ", 110, 111, 110);
 		case ZEND_AST_STATIC:
 			smart_str_appends(str, "static $");
 			zend_ast_export_name(str, ast->child[0], 0, indent);

Zend/zend_ast.h

@@ -115,6 +115,7 @@ enum _zend_ast_kind {
 	ZEND_AST_INSTANCEOF,
 	ZEND_AST_YIELD,
 	ZEND_AST_COALESCE,
+	ZEND_AST_EXCEPTION_COALESCE,
 
 	ZEND_AST_STATIC,
 	ZEND_AST_WHILE,

Zend/zend_compile.c

@@ -7313,6 +7313,21 @@ void zend_compile_coalesce(znode *result, zend_ast *ast) /* {{{ */
 }
 /* }}} */
 
+void zend_compile_exception_coalesce(znode *result, zend_ast *ast) /* {{{ */
+{
+	zend_ast *expr_ast = ast->child[0];
+	zend_ast *default_ast = ast->child[1];
+
+	zend_ast *hack = zend_ast_create_ex(ZEND_AST_INCLUDE_OR_EVAL, ZEND_EVAL,
+		zend_ast_create_zval_from_str(
+			zend_ast_export("try { return ", expr_ast, "; } catch(\\Throwable $e) {}")));
+
+	ast->child[0] = hack;
+
+	zend_compile_coalesce(result, ast);
+}
+/* }}} */
+
 void zend_compile_print(znode *result, zend_ast *ast) /* {{{ */
 {
 	zend_op *opline;
@@ -8266,6 +8281,9 @@ void zend_compile_expr(znode *result, zend_ast *ast) /* {{{ */
 		case ZEND_AST_COALESCE:
 			zend_compile_coalesce(result, ast);
 			return;
+		case ZEND_AST_EXCEPTION_COALESCE:
+			zend_compile_exception_coalesce(result, ast);
+			return;
 		case ZEND_AST_PRINT:
 			zend_compile_print(result, ast);
 			return;

Zend/zend_language_parser.y

@@ -64,6 +64,7 @@ static YYSIZE_T zend_yytnamerr(char*, const char*);
 %left '=' T_PLUS_EQUAL T_MINUS_EQUAL T_MUL_EQUAL T_DIV_EQUAL T_CONCAT_EQUAL T_MOD_EQUAL T_AND_EQUAL T_OR_EQUAL T_XOR_EQUAL T_SL_EQUAL T_SR_EQUAL T_POW_EQUAL
 %left '?' ':'
 %right T_COALESCE
+%right T_EXCEPTION_COALESCE
 %left T_BOOLEAN_OR
 %left T_BOOLEAN_AND
 %left '|'
@@ -219,6 +220,7 @@ static YYSIZE_T zend_yytnamerr(char*, const char*);
 %token T_NS_SEPARATOR    "\\ (T_NS_SEPARATOR)"
 %token T_ELLIPSIS        "... (T_ELLIPSIS)"
 %token T_COALESCE        "?? (T_COALESCE)"
+%token T_EXCEPTION_COALESCE        "??? (T_EXCEPTION_COALESCE)"
 %token T_POW             "** (T_POW)"
 %token T_POW_EQUAL       "**= (T_POW_EQUAL)"
 
@@ -961,6 +963,8 @@ expr_without_variable:
 			{ $$ = zend_ast_create(ZEND_AST_CONDITIONAL, $1, NULL, $4); }
 	|	expr T_COALESCE expr
 			{ $$ = zend_ast_create(ZEND_AST_COALESCE, $1, $3); }
+	|	expr T_EXCEPTION_COALESCE expr
+			{ $$ = zend_ast_create(ZEND_AST_EXCEPTION_COALESCE, $1, $3); }
 	|	internal_functions_in_yacc { $$ = $1; }
 	|	T_INT_CAST expr		{ $$ = zend_ast_create_cast(IS_LONG, $2); }
 	|	T_DOUBLE_CAST expr	{ $$ = zend_ast_create_cast(IS_DOUBLE, $2); }