in reply to Re: When the only tool you have is a screwdriver...
in thread When the only tool you have is a screwdriver...

Cleaning up (and making more clear) the parsing.

#!/usr/bin/perl

# http://perlmonks.org/?node_id=1144184

use strict;
use warnings;

sub e
  {
  /\Gua/gc ? return e() : /\Gu/gc || return 0;
  1 while (/\Gd/gc && e() && /\Gf/gc or /\Gb/gc) && e() or /\Gc/gc;
  return 1;
  }

for (qw( u udufu uau uu uc ubu ucbuc uaau ua uauau uccc uauuau ))
  {
  print e() && /\G\z/ ? "matches" : "   fail", "  $_\n";
  }

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Again, do you have a good set of test cases ?

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Re^3: When the only tool you have is a screwdriver...
by Anonymous Monk on Oct 09, 2015 at 02:29 UTC

    Adding random test cases found a weird frankenbug. Fixing backup seems to have fixed it. Do you have any good test cases ? 

    #!/usr/bin/perl -l

# http://perlmonks.org/?node_id=1144184

use strict;
use warnings;

sub e
  {
  my $p; 
  /\Gua/gc ? return e() : /\Gu/gc || return 0;
  1 while /\Gc/gc or
    ($p = pos(), /\Gb/gc && e() || (pos() = $p, 0)) or
    ($p = pos(), /\Gd/gc && e() && /\Gf/gc && e() || (pos() = $p, 0));
  return 1;
  }

for (qw( u udufu uau uu uc ubu ucbuc uaau ua uauau uccc uauuau
  udufuaua uaua uauau uccbucdc ))
  {
  print e() && /\G\z/gc ? "matches" : "   fail", "  $_";
  }

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[reply]
[d/l]

      s/frankenbug/heisenbug/

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