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PORegExp infinite loop only in perl, why?
 

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  1. PORegExp infinite loop only in perl, why?
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    <p>I have a regular expression to test whether a CSV cell contains a correct file path:</p> <p><strong>EDIT</strong> The CSV lists filepaths that does not yet exists when script runs (I cannot use -e), and filepath can include * or %variable% or {$variable}.</p> <pre><code>my $FILENAME_REGEXP = '^(|"|""")(?:[a-zA-Z]:[\\\/])?[\\\/]{0,2}(?:(?:[\w\s\.\*-]+|\{\$\w+}|%\w+%)[\\\/]{0,2})*\1$'; </code></pre> <p>Since CSV cells sometimes contains wrappers of double quotes, and sometimes the filename itself needs to be wrapped by double quotes, I made this grouping (|"|""") ... \1</p> <p>Then using this function:</p> <pre><code>sub ValidateUNCPath{ my $input = shift; if ($input !~ /$FILENAME_REGEXP/){ return; } else{ return "This is a Valid File Path."; } } </code></pre> <p>I'm trying to test if this phrase is matching my regexp (It should not match):</p> <pre><code>"""c:\my\dir\lord" </code></pre> <p>but my dear Perl gets into infinite loop when:</p> <pre><code>ValidateUNCPath('"""c:\my\dir\lord"'); </code></pre> <p><strong>EDIT</strong> actually it loops on this:</p> <pre><code>ValidateUNCPath('"""\aaaaaaaaa\bbbbbbb\ccccccc\Netwxn00.map"'); </code></pre> <p>I made sure in <a href="http://regexpal.com" rel="nofollow">http://regexpal.com</a> that my regexp correctly catches those non-symmetric """ ... " wrapping double quotes, but Perl got his own mind :(</p> <p>I even tried the /g and /o flags in </p> <pre><code>/$FILENAME_REGEXP/go </code></pre> <p>but it still hangs. What am I missing ? </p>
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    1. USNoam Manos
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    1. COThere is no code you have posted that can cause an infinite loop.
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    2. COinstead of return; try return "";
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      1. USHitham S. AlQadheeb
    3. COThe syntax `if (...) return; else return;` would cause a syntax error in perl... why don't you paste your *real* code, including the loop you are using, then we might be able to help you.
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