Replacing comments in php with preg_replace

Question

I need to replace all block comments with preg_replace() in php. For example:

/**asdfasdf
fasdfasdf*/
echo "hello World\n";

For this:

echo "hello World\n";

I tried some solutions from this site, but no one works for me. My code:

$file  = file_get_contents($fileinput);
$file = preg_replace('/\/\*([^\\n]*[\\n]?)*\*\//', '', $file);
echo $file;

My output for example is same as input.Link to my regex test

possible duplicate of [How to remove JS comments using PHP?](http://stackoverflow.com/questions/19509863/how-to-remove-js-comments-using-php) — Amal Murali, Mar 06 '14 at 15:47
I know but it's not correct for me .. For example if i have echo"/*asdfasdf*/" it will delete it and output will be like echo"" — Jakub Baski Gabčo, Mar 06 '14 at 15:50
http://www.php.net/manual/en/function.php-strip-whitespace.php — Thomas Ruiz, Mar 06 '14 at 15:53
@JakubBaskiGabčo: Then please edit your question and explain all the requirements clearly. — Amal Murali, Mar 06 '14 at 15:55
This probably isn't a good job for preg_replace - as PHP isn't a regular language, you're going to have trouble with comments that are in and out of strings. You can get close, but what you really want is probably some kind of tokenizer for PHP which will issue you COMMENT_START and COMMENT_END tokens. — FrankieTheKneeMan, Mar 06 '14 at 15:56
Regular expressions are not a magic wand you wave at every problem that happens to involve text data. — Andy Lester, Mar 06 '14 at 16:23

Robin Webdev · Answer 1 · 2014-03-06T16:17:21.703

Use the http://www.php.net/manual/en/function.token-get-all.php:

$file  = file_get_contents($fileinput);
$tokens = token_get_all($file); // prepend an open tag if your file doesnt have one

$plain = '';
foreach ($tokens as $token) {
    if (is_array($token)) {
        list($number, $string) = $token;
        if (!in_array($number, [T_OPEN_TAG, T_COMMENT])) { // add all tokens you dont want
             $plain .= $string;
        }
    } else {
        $plain .= $token;
    }
}
print_r($plain);

Output:

 echo "hello World\n";

Here is a list of all PHP tokens:

http://www.php.net/manual/en/tokens.php

score 0 · Answer 2 · answered Mar 06 '14 at 15:59

0

Try this

$file = preg_replace('/^\s*?\/\*.*?\*\//m', '', $file);

answered Mar 06 '14 at 15:59

Andrew

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Casimir et Hippolyte · Answer 3 · 2014-03-06T17:44:42.140

0

The best way to parse PHP code is to use the tokenizer.

However it is not so difficult to do it with a regex. You must only skip all strings:

$pattern = <<<'EOD'
~
(?(DEFINE)
    (?<sq> ' (?>[^'\\]++|\\{2}|\\.)* ' )   # single quotes
    (?<dq> " (?>[^"\\]++|\\{2}|\\.)* " )   # double quotes
    (?<hd> <<< \s* (["']?)(\w+)\g{-2} \R .*? (?<=\n) \g{-1} ;? (\R|$) ) # heredoc like
    (?<string> \g<sq> | \g<dq> | \g<hd>)
)
\g<string> (*SKIP)(*FAIL) | /\* .*? \*/
~xs
EOD;

$result = preg_replace($pattern, '', $data);

edited Mar 06 '14 at 17:44

answered Mar 06 '14 at 16:13

Casimir et Hippolyte

88,009
5
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Can you please convert it in one line regex, because i don't know how to do that? And can you also fix it? Doesn't work for single line comment (// ...). Thx. – Valentin Tanasescu Sep 02 '18 at 12:37
1

@ValentinTanasescu: Comments are not the place to ask questions. Also, there is nothing to fix since the question is how to remove block comments, not single line comments. – Casimir et Hippolyte Sep 02 '18 at 15:29

Replacing comments in php with preg_replace

3 Answers3