On 01/17/2016 06:07 PM, Tom Browder wrote:
> I'm trying to write all new Perl code in Perl 6. One thing I need is
> the equivalent of the Perl 5 qr// and, following Perl 6 docs, I've
> come to use something like this (I'm trying to ignore certain
> directories):
>
> # regex of dirs to ignore
> my regex dirs {
> \/home\/user\/\.cpan |
> \/home\/tbrowde\/\.emacs
> }
Better written as
my regex dirs {
| '/home/user/.cpan'
| '/home/tbowde/.emacs'
}
Yes, quoting does now work in regexes too. Cool, right? :-)
(The leading | is ignored, it just allows you to format the alternation
more consistently)
> for "dirlist.txt".IO.lines -> $line {
> # ignore certain dirs
> if $line ~~ m{<dirs>} {
> next;
> }
> }
>
> My question: Is there a way to have Perl 6 do the required escaping
> for the regex programmatically, i.e., turn this:
>
> my $str = '/home/usr/.cpan';
>
> into this:
>
> my regex dirs {
> \/home\/usr\/\.cpan
> }
>
> automatically?
Even better: No need to escape anymore. If you use $str in a regex, and
it actually contains a Str, it is always taken to match literally, so
my $dir1 = '/home/user/.cpan';
my $dir2 = '/home/tbowde/.emacs';
my regex ignore_dirs { $dir1 | $dir2 }
does what you want.
If you want the interpolated string to be treated as a regex, you have
to use it as my regex dirs { <$dir1> }.
Cheers,
Moritz
