Also, you can make this conditional: show me all the comment lines of a source
file:
$ perl6 -e '.say if .starts-with('#') for lines' source-file
> On 29 Jul 2019, at 10:06, Richard Hainsworth <[email protected]> wrote:
>
> Also no need for all the brackets
>
> .say for lines;
>
> This is quite idiomatic Perl 6 and not golfing
>
> On Mon, 29 Jul 2019, 07:13 Joseph Brenner, <[email protected]> wrote:
> > Hmmm. I would expect that to be in the Perl 5 to Perl 6 Migration Guides,
> > but I do not see it there.
>
> Exactly, I was just looking there, and I ended up playing around with
> the method form of lines, and didn't think to try the function
> form of it.
>
> To summarize, if the goal is to write a "simple_echo" script that
> can work with a file name or with lines on standard input:
>
> simple_echo lines.txt
> cat lines.txt | simple_echo
>
> The perl5 version would probably be:
>
> #!/usr/bin/env perl
> while(<>){
> print;
> }
>
> The perl6 version would be something like:
>
> #!/usr/bin/env perl6
> use v6;
> for lines() {
> say $_;
> }
>
>
> The kind of thing I was playing with was:
>
> #!/usr/bin/env perl6
> use v6;
> my @lines = $*ARGFILES.IO.lines;
> say @lines;
>
> That works for lines from a file, but not from standard input, and the
> error message isn't tremendously helpful:
>
> No such method 'lines' for invocant of type 'IO::Special'
>
>
>
>
> On 7/28/19, Bruce Gray <[email protected]> wrote:
> >
> >
> >> On Jul 28, 2019, at 6:20 PM, Joseph Brenner <[email protected]> wrote:
> >>
> >> I was just wondering if there's some direct analog in perl6 to the
> >> perl5 construct:
> >>
> >> while(<>){ ... }
> >>
> >> If I'm planning on passing a filename on the command-line, I can just
> >> get it out of $*ARGFILES easily enough, but what if I also wanted it
> >> to work on lines passed in via standard input?
> >
> >
> > `lines` , as a sub instead of a method, and no arguments.
> >
> > See: https://docs.perl6.org/routine/lines#(Cool)_routine_lines
> > Without any arguments, sub lines operates on $*ARGFILES, which
> > defaults to
> > $*IN in the absence of any filenames.
> >
> > For example:
> > perl6 -e 'say .join("\t") for lines().rotor(4);' path/to/file.txt
> >
> > Hmmm. I would expect that to be in the Perl 5 to Perl 6 Migration Guides,
> > but I do not see it there.
> >
> > —
> > Hope this helps,
> > Bruce Gray (Util of PerlMonks)
> >
> >
