php关键词自动添加span标签与关键词高亮代码

// Example use: $spanned = codeWords($string_containing_keywords);
// My site: andrew.dx.am
// Using colour==blue, but different arrays of words and different
// colours can be added.
function onlyWholeWords(&$value, $key) {
// Ignores words after // comment delimiters.
//$value = "/b(" . $value . ")b/";  // doesn't handle comments
//$value = "/^(?:(?!//).)*Kb(" . $value . ")b/";
// K lookbehind alternative is not supported in PHP < 5.2.4, so use:
  $value = "/^((?:(?!//).)*)b" . $value . "b/";
}
function addSpan(&$value, $key, $color='blue') {
  $value = "$1<span style='color:$color'>" . $value . "</span>";
}
function codeWords($code) {
  $keywords = array('as', 'break', 'case', 'class',
  'continue', 'default', 'do', 'elif', 'else',
  'elseif', 'for', 'foreach', 'function', 'if',
  'new', 'null', 'return', 'self', 'switch',
  'this', 'to', 'typeof', 'until',
  'var', 'void', 'while', 'with');
  $keywords2 = $keywords;
  array_walk($keywords, 'onlyWholeWords');
  array_walk($keywords2, 'addSpan', 'blue');
  $code = preg_replace($keywords, $keywords2, $code);
  return $code;
}

<?php
$link = array(
'百度,http://www.baidu.com/',
'php教程,http://www.jb200.com/wb/php/',
'脚本学堂,http://www.jb200.com/',
);
$str = '在百度中搜索php教程就可以到脚本学堂提供的php编程文章<br />
此处放置需要替换的内容。';
$out=keylink($str,$link,1); //$str 原始字符 $link，替换链接数组, 3替换次数
echo $out;
function _sortDesc($a, $b) {
return (strlen($a[0]) < strlen($b[0])) ? 1 : -1;
}
function keylink($str,$link,$count=1)
{
$linkDefs = $link;
$linkMap = array();
foreach($linkDefs as $row) {
$linkMap[] = explode(',', $row);
}

foreach($linkMap as $row) {
$str = preg_replace('/(<a.*?>s*)('.$row[0].')(s*</a>)/sui', '${2}', $str);
}

usort($linkMap, '_sortDesc');

$tmpKwds = array();

foreach($linkMap as $i=>$row) {
list($kwd, $url) = $row;
for($j=$i+1; $j<count($linkMap); $j++) {
$subKwd = $linkMap[$j][0];
//如果包含其他关键字，暂时替换成其他字符串
if(strpos($kwd, $subKwd) !== false) {
$tmpKwd = '{'.md5($subKwd).'}';
$kwd = str_replace($subKwd, $tmpKwd, $kwd);
$tmpKwds[$tmpKwd] = $subKwd;
}
}
//把文字替换成链接
$str = preg_replace('/('.$row[0].')/sui', '<a href="'.$row[1].'" target="_blank">'.$kwd.'</a>', $str, $count);
}

//把代替子关键字的字符串替换回来
foreach($tmpKwds as $tmp=>$kwd) {
$str = str_replace($tmp, $kwd, $str);
}
return $str;
}
?>