Re: Poor Man's Perl6 Exegesis (you get what you pay for)

[mikfire]

I will take a pass at this for loop:

for(@options) {
   my($sign, $name, $value)=/[+-]([[\w]&&[^\d]]\w+)(?:=(.*))?/s;
   # this looks like a typo - there should be parens around
   # the [+-]?
   my $targ := ${$Exporter::From::{$name}};

   given($sign) {
      when('+'): {
          if(defined $value) {
              $targ=$value;
          }
          else {
              $targ is true;
          }
      }

      when('-') {
          if($targ.props{true}) {
              $targ is false;
          }
          else {
              undef $targ;
          }
      }
   }
}

If I have understood what I have read ( which is a mighty large conditional ), the first two lines are pretty much identical to any perl5 code. The third line creates an alias between the $targ and the variable in Exporter::From symbol table ( which looks to be a really, really neat feature ).

We then switch on the sign. If the sign is a '+' and a value is given, we simply assign the provided value to $targ. If no value is given, we assume it is a boolean flag and set $targ to be true. This is being done by an actual property associated with $targ, not by assigning some non-zero value. This is done, I assume, so we can easily distinguish those annoying "0 but true" cases.

Similarly, if the sign is '-' we check the 'true' property. If that is set, we assume this is a boolean flag and set it false. Otherwise, we simply undef the value.

Pretty straight forward, I think. But I really like the way perl6 is shaping up.

Thanks for the write up Ovid.

Mik
mikfire