> #! /usr/bin/perl -w
> use warnings;
> use strict;
>
> sub element($$;%)
> {
>    my ($name, $content, %attributes) = @_;
>
>    sub quotedattvalue($$)
>    {
>        my ($name, $value) = @_;
>
>        # print STDERR "q $name, $value\n";
>        $value =~ s/"/\"/g; # so we can safely use quotes
>        return '"' . $value . '"';
>    }
>
>    # make a list of att="value" pairs, each with a leading space:
>    # (could use join and map to do this too more succinctly,
>    # see perldoc -f map)
>    my $atts = "";
>    if (%attributes) {
>        foreach (keys %attributes) {
>            $atts .= " " .
>                $_ . '=' .  quotedattvalue($_, $attributes{$_})
>            ;
>        }
>    }
>
>    return "<${name}${atts}>${content}</${name}>";
> }
>
> my $text;
> {
>    local $/;
>    $text = <>;
> };
>
> $text =~ s{c d\K e f (?=g h)}{
>        element(
>            "found-you",
>            $&,
>            "rule" => "31",
>            "before" => "c d"
>        )
>    }gme;
>    print $text;
>
> # end

Liam, you are a genius. The effort and passion you put into your
response is commendable! Thanks a stack. I'm working it through. Since
the nlptk (natural language processing toolkit) is written in Python,
I assumed for some reason that Python was better suited for text
processing in a modern world - but Perl seems quite readable, logical
and practical.

Thanks again for the effort! And friendly "hello world" in Perl.

Kind regards,
Jacobus