vit has asked for the wisdom of the Perl Monks concerning the following question:

Dear Monks,
Does anybody know a package or a piece of code which can highlight text (not language syntax).
Basically what I need is having a text string which contains regular text attributes (letters, spaces, commas, ....) to highlight those words which match a given query by inserting HTML bolds.
Say I for query "car repair" a phrase will be highlighted as "best car wash and repair!!".
  • Comment on Text highlighting (not language syntax)

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Re: Text highlighting (not language syntax)
by ikegami (Patriarch) on Jan 22, 2010 at 22:57 UTC
    Hum, not easy. You need a parser. This one should do the trick if you're starting from text. 
    use HTML::Entities qw( encode_entities );

sub text_to_html {
    my $terms = $_[1];

    my ($terms_pat) =
        map "(?:$_)",
        join '|',
        map quotemeta,
        @$terms;

    ( my $html = $_[0] ) =~
        s{
            ( (?: (?!$terms_pat). )* )
            ( $terms_pat+ )
        |
            ( .+ )
        }{
            defined($1)
                ? encode_entities("$1") .
                  "<b>" . encode_entities("$2") . "</b>"
                : encode_entities("$3")
        }xseg;

    return $html;
}

print text_to_html("best car wash & repair!!", [qw( car repair )]);

    [download]

    Starting from HTML is much trickier.

    Update: Simplified code.
    Update: Fixed s// </b> / problem mentioned in a reply.

[reply]
[d/l]
[select]
      Thanks, I am starting from text. I tested and got 
      Undefined subroutine &main::escaped_entities called at test_highlight.
+pl line 24.

      [download]
[reply]
[d/l]
        Should have been encode_entities, and it's available from HTML::Entities. See my updated code.
[reply]
[d/l]
Re: Text highlighting (not language syntax)
by zentara (Cardinal) on Jan 23, 2010 at 11:44 UTC
[reply]

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