Merge branch 'generators'

* generators: (70 commits)
  Fix typos
  Fix segfault when traversing a by-ref generator twice
  Make sure that exception is thrown on rewind() after closing too
  Remove implementation stubs for yield delegation
  Fix several issues and allow rewind only at/before first yield
  Run finally if generator is closed before finishing
  Finally with return now works in generators too
  Add dedicated opcode for returns from a generator
  Disallow serialization and unserialization
  Fix zts build (typo)
  Drop Generator::close() method
  Forgot to add test
  Support trivial finally in generators (no yield, no return)
  Fix implementation of Iterator interface
  Add T_YIELD in tokenizer_data.c
  Throw error also for return occuring before yield
  Fix throwing of exceptions within a generator
  Remove reference restrictions from foreach
  Require parenthesis around yield expressions
  Add some more tests
  ...

Zend/Makefile.am

@@ -17,7 +17,8 @@ libZend_la_SOURCES=\
 	zend_objects_API.c zend_ts_hash.c zend_stream.c \
 	zend_default_classes.c \
 	zend_iterators.c zend_interfaces.c zend_exceptions.c \
-	zend_strtod.c zend_closures.c zend_float.c zend_string.c zend_signal.c
+	zend_strtod.c zend_closures.c zend_float.c zend_string.c zend_signal.c \
+	zend_generators.c
 
 libZend_la_LDFLAGS =
 libZend_la_LIBADD = @ZEND_EXTRA_LIBS@

Zend/tests/foreach_temp_array_expr_with_refs.phpt

@@ -0,0 +1,18 @@
+--TEST--
+Temporary array expressions can be iterated by reference
+--FILE--
+<?php
+
+$a = 'a';
+$b = 'b';
+
+foreach ([&$a, &$b] as &$value) {
+    $value .= '-foo';
+}
+
+var_dump($a, $b);
+
+?>
+--EXPECT--
+string(5) "a-foo"
+string(5) "b-foo"

Zend/tests/generators/auto_incrementing_keys.phpt

@@ -0,0 +1,22 @@
+--TEST--
+Generator keys are auto-incrementing by default
+--FILE--
+<?php
+
+function gen() {
+    yield 'foo';
+    yield 'bar';
+    yield 5 => 'rab';
+    yield 'oof';
+}
+
+foreach (gen() as $k => $v) {
+    echo $k, ' => ', $v, "\n";
+}
+
+?>
+--EXPECT--
+0 => foo
+1 => bar
+5 => rab
+6 => oof

Zend/tests/generators/backtrace.phpt

@@ -0,0 +1,27 @@
+--TEST--
+Printing the stack trace in a generator
+--FILE--
+<?php
+
+function f1() {
+    debug_print_backtrace();
+}
+
+function f2($arg1, $arg2) {
+    f1();
+    yield; // force generator
+}
+
+function f3($gen) {
+    $gen->rewind(); // trigger run
+}
+
+$gen = f2('foo', 'bar');
+f3($gen);
+
+?>
+--EXPECTF--
+#0  f1() called at [%s:%d]
+#1  f2(foo, bar)
+#2  Generator->rewind() called at [%s:%d]
+#3  f3(Generator Object ()) called at [%s:%d]

Zend/tests/generators/clone.phpt

@@ -0,0 +1,32 @@
+--TEST--
+Generators can be cloned
+--FILE--
+<?php
+
+function firstN($end) {
+    for ($i = 0; $i < $end; ++$i) {
+        yield $i;
+    }
+}
+
+$g1 = firstN(5);
+var_dump($g1->current());
+$g1->next();
+
+$g2 = clone $g1;
+var_dump($g2->current());
+$g2->next();
+
+var_dump($g2->current());
+var_dump($g1->current());
+
+$g1->next();
+var_dump($g1->current());
+
+?>
+--EXPECT--
+int(0)
+int(1)
+int(2)
+int(1)
+int(2)

Zend/tests/generators/clone_with_foreach.phpt

@@ -0,0 +1,33 @@
+--TEST--
+Cloning a generator with a foreach loop properly adds a ref for the loop var
+--FILE--
+<?php
+
+function gen() {
+    foreach ([1, 2, 3] as $i) {
+        yield $i;
+    }
+}
+
+$g1 = gen();
+var_dump($g1->current());
+
+$g2 = clone $g1;
+var_dump($g2->current());
+
+$g1->next();
+$g2->next();
+var_dump($g1->current());
+var_dump($g2->current());
+
+unset($g1);
+$g2->next();
+var_dump($g2->current());
+
+?>
+--EXPECT--
+int(1)
+int(1)
+int(2)
+int(2)
+int(3)

Zend/tests/generators/clone_with_stack.phpt

@@ -0,0 +1,18 @@
+--TEST--
+A generator with an active stack can be cloned
+--FILE--
+<?php
+
+function gen() {
+    var_dump(str_repeat("x", yield));
+}
+
+$g1 = gen();
+$g1->rewind();
+$g2 = clone $g1;
+unset($g1);
+$g2->send(10);
+
+?>
+--EXPECT--
+string(10) "xxxxxxxxxx"

Zend/tests/generators/clone_with_symbol_table.phpt

@@ -0,0 +1,27 @@
+--TEST--
+A generator using a symbol table can be cloned
+--FILE--
+<?php
+
+function gen() {
+    // force compiled variable for $foo
+    $foo = 'foo';
+
+    // force symbol table
+    extract(['foo' => 'bar']);
+
+    // interrupt
+    yield;
+
+    var_dump($foo);
+}
+
+$g1 = gen();
+$g1->rewind();
+$g2 = clone $g1;
+unset($g1);
+$g2->next();
+
+?>
+--EXPECT--
+string(3) "bar"

Zend/tests/generators/clone_with_this.phpt

@@ -0,0 +1,24 @@
+--TEST--
+Cloning a generator method (with $this)
+--FILE--
+<?php
+
+class Test {
+    protected $foo;
+
+    public function gen() {
+        $this->foo = 'bar';
+        yield; // interrupt
+        var_dump($this->foo);
+    }
+}
+
+$g1 = (new Test)->gen();
+$g1->rewind(); // goto yield
+$g2 = clone $g1;
+unset($g1);
+$g2->next();
+
+?>
+--EXPECT--
+string(3) "bar"

Zend/tests/generators/dynamic_call.phpt

@@ -0,0 +1,19 @@
+--TEST--
+It's possible to invoke a generator dynamically
+--FILE--
+<?php
+
+function gen($foo, $bar) {
+    yield $foo;
+    yield $bar;
+}
+
+$gen = call_user_func('gen', 'bar', 'foo');
+foreach ($gen as $value) {
+    var_dump($value);
+}
+
+?>
+--EXPECT--
+string(3) "bar"
+string(3) "foo"

Zend/tests/generators/errors/generator_cannot_return_before_yield_error.phpt

@@ -0,0 +1,13 @@
+--TEST--
+Generators cannot return values (even before yield)
+--FILE--
+<?php
+
+function gen() {
+    return $foo;
+    yield;
+}
+
+?>
+--EXPECTF--
+Fatal error: Generators cannot return values using "return" in %s on line 4

Zend/tests/generators/errors/generator_cannot_return_error.phpt

@@ -0,0 +1,13 @@
+--TEST--
+Generators cannot return values
+--FILE--
+<?php
+
+function gen() {
+    yield;
+	return $abc;
+}
+
+?>
+--EXPECTF--
+Fatal error: Generators cannot return values using "return" in %s on line 5

Zend/tests/generators/errors/generator_extend_error.phpt

@@ -0,0 +1,10 @@
+--TEST--
+The Generator class cannot be extended
+--FILE--
+<?php
+
+class ExtendedGenerator extends Generator { }
+
+?>
+--EXPECTF--
+Fatal error: Class ExtendedGenerator may not inherit from final class (Generator) in %s on line %d

Zend/tests/generators/errors/generator_instantiate_error.phpt

@@ -0,0 +1,10 @@
+--TEST--
+It's not possible to directly instantiate the Generator class
+--FILE--
+<?php
+
+new Generator;
+
+?>
+--EXPECTF--
+Catchable fatal error: The "Generator" class is reserved for internal use and cannot be manually instantiated in %s on line %d

Zend/tests/generators/errors/non_ref_generator_iterated_by_ref_error.phpt

@@ -0,0 +1,18 @@
+--TEST--
+Non-ref generators cannot be iterated by-ref
+--FILE--
+<?php
+
+function gen() { yield; }
+
+$gen = gen();
+foreach ($gen as &$value) { }
+
+?>
+--EXPECTF--
+Fatal error: Uncaught exception 'Exception' with message 'You can only iterate a generator by-reference if it declared that it yields by-reference' in %s:%d
+Stack trace:
+#0 %s(%d): unknown()
+#1 {main}
+  thrown in %s on line %d
+

Zend/tests/generators/errors/resume_running_generator_error.phpt

@@ -0,0 +1,17 @@
+--TEST--
+It is not possible to resume an already running generator
+--FILE--
+<?php
+
+function gen() {
+    $gen = yield;
+    $gen->next();
+}
+
+$gen = gen();
+$gen->send($gen);
+$gen->next();
+
+?>
+--EXPECTF--
+Fatal error: Cannot resume an already running generator in %s on line %d