Is your question really about how to prevent $query="perl"; from matching anything in "This drink is fraperliscious!"? 

$str =~ s/\b\Q$query\E\b/<em>$query<\/em>/ig;

[download]

or 

$str =~ s/(?<!\w)\Q$query\E(?!\w)/<em>$query<\/em>/ig;

[download]

In reply to Re: How to use \W in Regular Expression? by ikegami
in thread How to use \W in Regular Expression? by Sachin

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