PHP正则替换函数preg_replace和preg_replace_callback使用总结

<?php
/**
 * 模板解析类
 */
class Template {

 public function compile($template) {

  // if逻辑
  $template = preg_replace("/\<\!\-\-\{if\s+(.+?)\}\-\-\>/e", "\$this->ifTag('\\1')", $template);

  return $template;
 }

 /**
  * if 标签
  */
 protected function ifTag($str) {

  //$str = stripslashes($str); // 去反转义

  return '<?php if (' . $str . ') { ?>';
 }
}

$template = 'xxx<!--{if $user[\'userName\']}-->yyy<!--{if $user["password"]}-->zzz';

$tplComplier = new Template();

$template = $tplComplier->compile($template);

echo $template;

?>

xxx<?php if ($user['userName']) { ?>yyy<?php if ($user[\"password\"]) { ?>zzz

mixed preg_replace_callback ( mixed pattern, callback callback, mixed subject [, int limit] )
本函数的行为几乎和 preg_replace() 一样，除了不是提供一个 replacement 参数，而是指定一个 callback 函数。该函数将以目标字符串中的匹配数组作为输入参数，并返回用于替换的字符串。

string handler ( array $matches )

<?php
/* 一个unix样式的命令行过滤器，用于将段落开始部分的大写字母转换为小写。 */
$fp = fopen("php://stdin", "r") or die("can't read stdin");
while (!feof($fp)) {
    $line = fgets($fp);
    $line = preg_replace_callback(
        '|<p>\s*\w|',
        function ($matches) {
            return strtolower($matches[0]);
        },
        $line
    );
    echo $line;
}
fclose($fp);
?>

<?php
$string = "Some numbers: one: 1; two: 2; three: 3 end";
$ten = 10;
$newstring = preg_replace_callback(
    '/(\\d+)/',
    function($match) use ($ten) { return (($match[0] + $ten)); },
    $string
    );
echo $newstring;
#prints "Some numbers: one: 11; two: 12; three: 13 end";
?>

<?php
// 将文本中的年份增加一年.
$text = "April fools day is 04/01/2002\n";
$text.= "Last christmas was 12/24/2001\n";
// 回调函数
function next_year($matches) {
  // 通常: $matches[0]是完成的匹配
  // $matches[1]是第一个捕获子组的匹配
  // 以此类推
  return $matches[1].($matches[2]+1);
}
echo preg_replace_callback(
            "|(\d{2}/\d{2}/)(\d{4})|",
            "next_year",
            $text);

?>

<?php
class test_preg_callback{

  private function process($text){
    $reg = "/\{([0-9a-zA-Z\- ]+)\:([0-9a-zA-Z\- ]+):?\}/";
    return preg_replace_callback($reg, array($this, 'replace'), $text);
  }
 
  private function replace($matches){
    if (method_exists($this, $matches[1])){
      return @$this->$matches[1]($matches[2]);    
    }
  } 
}
?>

<?php
class test_preg_callback{

  private function process($text){
    $reg = "/\{([0-9a-zA-Z\- ]+)\:([0-9a-zA-Z\- ]+):?\}/";
    return preg_replace_callback($reg, "self::replace", $text);
  }
 
  private function replace($matches){
    if (method_exists($this, $matches[1])){
      return @$this->$matches[1]($matches[2]);    
    }
  } 
}
?>

<?php
/**
 * 模板解析类
 */
class Template {

 public function compile($template) {

  // if逻辑
  $template = preg_replace_callback("/\<\!\-\-\{if\s+(.+?)\}\-\-\>/", array($this, 'ifTag'), $template);

  return $template;
 }

 /**
  * if 标签
  */
 protected function ifTag($matches) {
  return '<?php if (' . $matches[1] . ') { ?>';
 }
}

$template = 'xxx<!--{if $user[\'userName\']}-->yyy<!--{if $user["password"]}-->zzz';

$tplComplier = new Template();

$template = $tplComplier->compile($template);

echo $template;

?>

xxx<?php if ($user['userName']) { ?>yyy<?php if ($user["password"]) { ?>zzz