Re: Text highlighting (not language syntax)

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.

Comment on Re: Text highlighting (not language syntax) Select or Download Code

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Re^2: Text highlighting (not language syntax) by vit (Friar) on Jan 22, 2010 at 23:09 UTC
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]
Re^3: Text highlighting (not language syntax) by ikegami (Patriarch) on Jan 22, 2010 at 23:09 UTC
Should have been `encode_entities`, and it's available from HTML::Entities. See my updated code.	[reply] [d/l]
Re^4: Text highlighting (not language syntax) by vit (Friar) on Jan 22, 2010 at 23:25 UTC
Still a problem Bareword found where operator expected at test_highlight.pl line 21, n +ear ""<b>" . encode_entities("$2") . "</b" (Might be a runaway multi-line // string starting on line 13) (Missing operator before b?) Scalar found where operator expected at test_highlight.pl line 22, nea +r ": encode_entities("$3" (Might be a runaway multi-line "" string starting on line 21) (Missing operator before $3?) String found where operator expected at test_highlight.pl line 28, nea +r "print text_to_html("" (Might be a runaway multi-line "" string starting on line 22) (Missing semicolon on previous line?) Bareword found where operator expected at test_highlight.pl line 28, n +ear "print text_to_html("best" (Do you need to predeclare print?) syntax error at test_highlight.pl line 21, near ""<b>" . encode_entiti +es("$2") . "</b" Can't find string terminator '"' anywhere before EOF at test_highlight +.pl line 28. [download] Got it, should be `"<\/b>"` [download]	[reply] [d/l] [select]