Make $generator->send() return the current value

This makes the API easier to use (and is consistent with Python and JS).

Zend/tests/generators/send_returns_current.phpt

@@ -0,0 +1,20 @@
+--TEST--
+$generator->send() returns the yielded value
+--FILE--
+<?php
+
+function *reverseEchoGenerator() {
+    $data = yield;
+    while (true) {
+        $data = yield strrev($data);
+    }
+}
+
+$gen = reverseEchoGenerator();
+var_dump($gen->send('foo'));
+var_dump($gen->send('bar'));
+
+?>
+--EXPECT--
+string(3) "oof"
+string(3) "rab"

Zend/zend_generators.c

@@ -336,7 +336,7 @@ ZEND_METHOD(Generator, next)
 }
 /* }}} */
 
-/* {{{ proto void Generator::send()
+/* {{{ proto mixed Generator::send()
  * Sends a value to the generator */
 ZEND_METHOD(Generator, send)
 {
@@ -366,6 +366,10 @@ ZEND_METHOD(Generator, send)
 	generator->send_target->var.ptr_ptr = &value;
 
 	zend_generator_resume(object, generator TSRMLS_CC);
+
+	if (generator->value) {
+		RETURN_ZVAL(generator->value, 1, 0);
+	}
 }
 
 /* {{{ proto void Generator::close()