PHP教程：浅谈php7的重大新特性

ZEND引擎升级到Zend Engine 3,也就是所谓的PHP NG
增加抽象语法树,使编译更加科学
64位的INT支持
统一的变量语法
原声的TLS - 对扩展开发有意义
一致性foreach循环的改进
新增 <=>、**、?? 、\u{xxxx}操作符
增加了返回类型的声明
增加了标量类型的声明
核心错误可以通过异常捕获了
增加了上下文敏感的词法分析

//PHP5
"0x10" == "16"
//PHP7
"0x10" != "16"

function test ($num) {
  $num++;
  var_dump(func_get_args()[0]);
};
test(1)
//PHP5
int(1)
//PHP7
int(2)

call_user_function(_array) => ZEND_INIT_USER_CALL
is_int/string/array/* => ZEND_TYPE_CHECK
strlen => ZEND_STRLEN
defined => ZEND+DEFINED

//PHP5 - 快速排序(非稳定排序)
array(1 => 0, 0 => 0)
//PHP7 - 快速排序+选择排序(稳定排序)
array(0 => 0, 1 => 0)

$$foo['bar']['baz']
//PHP5
($$foo)[‘bar']['baz']
//PHP7: 遵循从左到右的原则
${$foo[‘bar']['baz']}

//PHP5
$a = array(1, 2, 3);foreach ($a as $v){var_dump(current($a));}
int(2)
int(2)
int(2)
$a = array(1, 2, 3);$b=&$a;foreach ($a as $v){var_dump(current($a));}
int(2)
int(3)
bool(false)
$a = array(1, 2, 3);$b=$a;foreach ($a as $v){var_dump(current($a));}
int(1)
int(1)
int(1)
//PHP7：不再操作数据的内部指针了
$a = array(1, 2, 3);foreach ($a as $v){var_dump(current($a))}
int(1)
int(1)
int(1)
$a = array(1, 2, 3);$b=&$a;foreach ($a as $v){var_dump(current($a))
int(1)
int(1)
int(1)
$a = array(1, 2, 3);$b=$a;foreach ($a as $v){var_dump(current($a))}
int(1)
int(1)
int(1)

//<=> - 比较两个数的大小【-1：前者小于后者,0：前者等于后者,1：前者大于后者】
echo 1 <=> 2;//-1
echo 1 <=> 1;//0
echo 1 <=> 0;//1
// ** - 【a的b次方】
echo 2 ** 3;//8
//?? - 三元运算符的改进
//php5
$_GET['name'] ? $_GET['name'] : '';//Notice: Undefined index: …
//php7
$_GET['name'] ?? '' -> '';
//\u{xxxx} - Unicode字符的解析
echo "\u{4f60}";//你
echo "\u{65b0}";//新

function getInt() : int {
  return “test”;
};
getInt();
//PHP5
#PHP Parse error: parse error, expecting '{'...
//PHP7
#Fatal error:Uncaught TypeError: Return value of getInt() must be of the type integer, string returned 

function getInt(int $num) : int {
  return $num;
};
getInt(“test”);
//PHP5
#PHP Catchable fatal error: Argument 1 passed to getInt() must be an instance of int, string given…
//PHP7
#Fatal error: Uncaught TypeError: Argument 1 passed to getInt() must be of the type integer, string given…

try {
  non_exists_func();
} catch(EngineException $e) {
  echo “Exception: {$e->getMessage();}\n”;
}
//这里用php7试了一下还是没法捕获,但是看鸟哥介绍说是可行的...
#Exception: Call to undefined function non_exists_func()

//PHP5
class Collection {public function foreach($arr) {}}
#Parse error: parse error, expecting `"identifier (T_STRING)”'...
//PHP7
class Collection {
  public function foreach($arr) {}
  public function in($arr){}
  public function where($condition){}
  public function order($condition){}
}
$collection = new Collection();
$collection->where()->in()->foreach()->order();