本文实例讲述了php闭包中使用use声明变量的作用域。分享给大家供大家参考,具体如下:
<?phpfunction getClosure($i){ $i = $i."-".date("H:i:s"); return function ($param) use ($i) { echo "--- param: $param ---"; echo "--- i: $i ---"; };}$c = getClosure(123);$i = 456;$c("test");sleep(3);$c2 = getClosure(123);$c2("test");$c("test");/*output:--- param: test ------ i: 123-21:36:52 ------ param: test ------ i: 123-21:36:55 ------ param: test ------ i: 123-21:36:52 ---*/
如上,闭包中使用use
声明的变量来自于生成闭包实例时所在作用域内的同名变量,而不是来自于运行闭包时所在作用域内的同名变量。
而闭包的函数参数则是和正常的函数参数一样来自于运行时所在作用域内的同名变量。
以下为opcode:
Finding entry pointsBranch analysis from position: 0Jump found. Position 1 = -2filename: /tmp/testclosure.phpfunction name: (null)number of ops: 20compiled vars: !0 = $c, !1 = $i, !2 = $c2line #* E I O op fetch ext return operands------------------------------------------------------------------------------------- 2 0 E > NOP 11 1 SEND_VAL 123 2 DO_FCALL 1 $0 "getclosure" 3 ASSIGN !0, $0 12 4 ASSIGN !1, 456 13 5 INIT_FCALL_BY_NAME !0 6 SEND_VAL "test" 7 DO_FCALL_BY_NAME 1 14 8 SEND_VAL 3 9 DO_FCALL 1 "sleep" 15 10 SEND_VAL 123 11 DO_FCALL 1 $5 "getclosure" 12 ASSIGN !2, $5 16 13 INIT_FCALL_BY_NAME !2 14 SEND_VAL "test" 15 DO_FCALL_BY_NAME 1 17 16 INIT_FCALL_BY_NAME !0 17 SEND_VAL "test" 18 DO_FCALL_BY_NAME 1 29 19 > RETURN 1Function %00%7Bclosure%7D%2Ftmp%2Ftestclosure.php0x7fb0115f505:Finding entry pointsBranch analysis from position: 0Jump found. Position 1 = -2filename: /tmp/testclosure.phpfunction name: {closure}number of ops: 12compiled vars: !0 = $param, !1 = $iline #* E I O op fetch ext return operands------------------------------------------------------------------------------------- 5 0 E > RECV !0 1 FETCH_R static $0 "i" 2 ASSIGN !1, $0 6 3 ADD_STRING ~2 "---+param%3A+" 4 ADD_VAR ~2 ~2, !0 5 ADD_STRING ~2 ~2, "+---%0A" 6 ECHO ~2 7 7 ADD_STRING ~3 "---+i%3A+" 8 ADD_VAR ~3 ~3, !1 9 ADD_STRING ~3 ~3, "+---%0A" 10 ECHO ~3 8 11 > RETURN nullEnd of function %00%7Bclosure%7D%2Ftmp%2Ftestclosure.php0x7fb0115f505Function getclosure:Finding entry pointsBranch analysis from position: 0Jump found. Position 1 = -2filename: /tmp/testclosure.phpfunction name: getClosurenumber of ops: 9compiled vars: !0 = $iline #* E I O op fetch ext return operands------------------------------------------------------------------------------------- 2 0 E > RECV !0 4 1 CONCAT ~0 !0, "-" 2 SEND_VAL "H%3Ai%3As" 3 DO_FCALL 1 $1 "date" 4 CONCAT ~2 ~0, $1 5 ASSIGN !0, ~2 5 6 DECLARE_LAMBDA_FUNCTION "%00%7Bclosure%7D%2Ftmp%2Ftestclosure.php0x7fb0115f5051" 8 7 > RETURN ~4 9 8* > RETURN nullEnd of function getclosure
如上,闭包函数的op_array
(相当于类定义)在编译期完成,但在运行期生成闭包实例(相当于类实例)时会为不同实例绑定不同的use
静态变量(在DECLARE_LAMBDA_FUNCTION中完成)。
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