Your concept of passing the condition only works when testing a global var like $_ and typechecking is vulnerable in edge cases.¹

I think my concept is more robust and any boolean test can be used.

Sometimes less is more.

use strict;
use warnings;

use Data::Dump;


{
    my %state;

    sub till {
        my @phases=@_;
        #dd \@_;
        my ($file,$line)= (caller)[1..2];
        my $state = \$state{$file,$line};
        $$state //= 0;
        $phases[1+$$state]->();
        if ($phases[$$state]) {
            $$state += 2;
            $$state %= @phases;
        }
    }
}


while (my $var = <DATA>){
    till (
        - ($var =~ /for/)   => sub { print "*: $var" },
        - ($var =~ /their/) => sub { print "1: $var" },
        - ($var =~ /fruit/) => sub { print "2: $var" },
        - ($var =~ /lazy/)  => sub { print "3: $var" },
       );
}

__DATA__
now is the time
for all good men to
come to the aid of
their party.
Time flies like an arrow
fruit flies like a  banana.
The quick red fox
jumps over the lazy
brown dog.
Etaoinshrdlu.

[download]

out

*: now is the time
*: for all good men to
1: come to the aid of
1: their party.
2: Time flies like an arrow
2: fruit flies like a  banana.
3: The quick red fox
3: jumps over the lazy
*: brown dog.
*: Etaoinshrdlu.

[download]

Cheers Rolf

(addicted to the Perl Programming Language and ☆☆☆☆ :)

¹) What if a test returns a reference for true? Enforcing negation with a unitary minus solves this issue.

In reply to Re^4: Multi-stage flip-flop? ( till() - proof of concept) by LanX
in thread Multi-stage flip-flop? by RonW

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.