正则表达式请教如何匹配

<code>"<?php if(<?php echo $this -> vars[a] ;?> == 'a') ?>"
"<?php if(<?php echo $this -> vars[a] ;?> != 'a') ?>"
"<?php if(<?php echo $this -> vars[a] ;?> > 'a') ?>"</code>

<code>> if(<?phps*echos*($thiss*->s*vars[.+?])s*;s*?>s*(.*?))</code>

<code>"<?php if(<?php echo $this -> vars[a] ;?> == 'a') ?>"
"<?php if(<?php echo $this -> vars[a] ;?> != 'a') ?>"
"<?php if(<?php echo $this -> vars[a] ;?> > 'a') ?>"</code>

<code>> if(<?phps*echos*($thiss*->s*vars[.+?])s*;s*?>s*(.*?))</code>

<code><?php

$str = "<?php if(<?php echo $this -> vars[a] ;?> == 'a') ?>";
preg_match('/<?phps*echos*($thiss*->s*vars[(['"]?)([A-Za-z0-9_]+)\2])s*;s*?>s*(==s*(['"]?)\3\5)/',$str,$match);
echo $match[1],$match[4];

?>
</code>

<code>/($thiss->svars[a]|(==s'a'))/g
</code>

<code>preg_match_all($pattern, $stringReg, $matches);

</code>

<code>var a = "<?php if(<?php echo $this -> vars[a] ;?> == 'a') ?>";
var re = /^.*s($thiss->svars[a]).*$/;
re.exec(a);
//["<?php if(<?php echo $this -> vars[a] ;?> == 'a') ?>", "$this -> vars[a]"]

var re2 = /^.*s(==s'a').*$/;
re2.exec(a)
//["<?php if(<?php echo $this -> vars[a] ;?> == 'a') ?>", "== 'a'"]
</code>