(PHP 4, PHP 5, PHP 7)
eval — 锟斤拷锟街凤拷锟斤拷锟斤拷为PHP锟斤拷锟斤拷执锟斤拷
锟斤拷锟街凤拷锟斤拷 code 锟斤拷为PHP锟斤拷锟斤拷执锟叫★拷
锟斤拷锟斤拷eval()锟斤拷锟皆结构锟斤拷 锟角筹拷危锟斤拷锟侥ｏ拷 锟斤拷为锟斤拷锟斤拷锟斤拷执锟斤拷锟斤拷锟斤拷 PHP 锟斤拷锟诫。 锟斤拷锟斤拷锟斤拷锟斤拷锟角猴拷危锟秸的★拷 锟斤拷锟斤拷锟斤拷锟较革拷锟饺凤拷瞎锟斤拷锟斤拷锟斤拷锟绞癸拷么私峁癸拷锟斤拷锟� 锟斤拷锟睫凤拷锟斤拷, 锟斤拷锟斤拷注锟解，锟斤拷要锟斤拷锟斤拷锟斤拷锟轿猴拷锟斤拷锟矫伙拷 锟结供锟侥★拷未锟斤拷锟斤拷锟斤拷锟斤拷证锟斤拷锟斤拷锟斤拷锟斤拷 锟斤拷
code锟斤拷要锟斤拷执锟叫碉拷锟街凤拷锟斤拷
锟斤拷锟诫不锟杰帮拷锟斤拷锟斤拷/锟截憋拷 PHP tags锟斤拷锟斤拷锟界， 'echo "Hi!";' 锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷锟诫： '<?php echo "Hi!"; ?>'锟斤拷锟斤拷锟斤拷然锟斤拷锟斤拷锟矫猴拷锟绞碉拷 PHP tag 锟斤拷锟诫开锟斤拷锟斤拷锟铰斤拷锟斤拷 PHP 模式锟斤拷锟斤拷锟斤拷 'echo "In PHP mode!"; ?>In HTML mode!<?php echo "Back in PHP mode!";'锟斤拷
锟斤拷锟斤拷之锟解，锟斤拷锟斤拷谋锟斤拷锟斤拷锟斤拷锟叫э拷锟� PHP 锟斤拷锟诫。锟斤拷锟叫碉拷锟斤拷锟斤拷锟斤拷锟皆分号斤拷尾锟斤拷锟斤拷锟斤拷 'echo "Hi!"' 锟结导锟斤拷一锟斤拷 parse error锟斤拷锟斤拷 'echo "Hi!";' 锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷小锟�
return 锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷止锟斤拷前锟街凤拷锟斤拷锟斤拷执锟叫★拷
锟斤拷锟斤拷执锟叫碉拷锟斤拷锟斤拷锟斤拷锟角碉拷锟斤拷 eval() 锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷耍锟�eval() 锟斤拷锟轿何的憋拷锟斤拷锟斤拷锟藉、锟睫改ｏ拷锟斤拷锟斤拷锟节猴拷锟斤拷锟斤拷锟斤拷锟襟被憋拷锟斤拷锟斤拷
eval() 锟斤拷锟斤拷 NULL锟斤拷锟斤拷锟斤拷锟斤拷执锟叫的达拷锟斤拷锟斤拷 return 锟斤拷一锟斤拷值锟斤拷锟斤拷锟斤拷锟斤拷锟截达拷锟捷革拷 return 锟斤拷值锟斤拷 PHP 7 锟斤拷始锟斤拷执锟叫的达拷锟斤拷锟斤拷锟斤拷锟斤拷锟揭伙拷锟� parse error锟斤拷eval() 锟斤拷锟阶筹拷 ParseError 锟届常锟斤拷锟斤拷 PHP 7 之前锟斤拷
锟斤拷锟斤拷锟街达拷械拇锟斤拷锟斤拷锟斤拷锟� parse error锟斤拷eval() 锟斤拷锟斤拷
FALSE锟斤拷之锟斤拷拇锟斤拷虢拷锟斤拷锟街达拷小锟斤拷薹锟绞癸拷锟� set_error_handler() 锟斤拷锟斤拷 eval() 锟叫的斤拷锟斤拷锟斤拷锟斤拷
Example #1 eval() 锟斤拷锟斤拷 - 锟津单碉拷锟侥憋拷锟较诧拷
<?php
$string = 'cup';
$name = 'coffee';
$str = 'This is a $string with my $name in it.';
echo $str. "\n";
eval("\$str = \"$str\";");
echo $str. "\n";
?>
锟斤拷锟斤拷锟斤拷锟教伙拷锟斤拷锟斤拷锟�
This is a $string with my $name in it. This is a cup with my coffee in it.
Note: 锟斤拷为锟斤拷一锟斤拷锟斤拷锟皆癸拷锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷一锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷锟杰憋拷 锟缴变函锟斤拷 锟斤拷锟矫★拷
锟斤拷直锟接斤拷锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷锟揭伙拷锟斤拷锟斤拷锟绞癸拷锟�锟斤拷锟斤拷锟斤拷坪锟斤拷锟�锟斤拷锟斤拷锟斤拷前锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷锟饺伙拷锟�(锟斤拷锟斤拷)锟斤拷锟芥到一锟斤拷 string 锟叫★拷
Note:
锟斤拷锟斤拷锟街达拷械拇锟斤拷锟斤拷胁锟斤拷锟斤拷锟揭伙拷锟斤拷锟斤拷锟斤拷拇锟斤拷锟絝atal error锟斤拷锟斤拷锟斤拷锟斤拷锟脚憋拷锟斤拷锟剿筹拷锟斤拷