Add support for yielding keys

Keys are yielded using the

    yield $key => $value

syntax. Currently this is implemented as a statement only and not as an
expression, because conflicts arise considering nesting and use in arrays:

    yield yield $a => $b;
    // could be either
    yield (yield $a) => $b;
    // or
    yield (yield $a => $b);

Once I find some way to resolve these conflicts this should be available
as an expression too.

Also the key yielding code is rather copy-and-past-y for the value yielding
code, so that should be factored out.

1 files changed, 9 insertions, 3 deletions

diff --git a/Zend/zend_compile.c b/Zend/zend_compile.c
index 89549bb6ed..da61b76662 100644
--- a/Zend/zend_compile.c
+++ b/Zend/zend_compile.c
@@ -2662,7 +2662,7 @@ void zend_do_return(znode *expr, int do_end_vparse TSRMLS_DC) /* {{{ */
 }
 /* }}} */
 
-void zend_do_yield(znode *result, const znode *expr TSRMLS_DC) /* {{{ */
+void zend_do_yield(znode *result, const znode *value, const znode *key TSRMLS_DC) /* {{{ */
 {
 	zend_op *opline;
 
@@ -2674,8 +2674,14 @@ void zend_do_yield(znode *result, const znode *expr TSRMLS_DC) /* {{{ */
 
 	opline->opcode = ZEND_YIELD;
 
-	if (expr) {
-		SET_NODE(opline->op1, expr);
+	if (value) {
+		SET_NODE(opline->op1, value);
+	} else {
+		SET_UNUSED(opline->op1);
+	}
+
+	if (key) {
+		SET_NODE(opline->op2, key);
 	} else {
 		SET_UNUSED(opline->op2);
 	}