[Pdx-pm] New DA question - sub return'd values

[Roderick A. Anderson]

On Thu, 8 Jan 2004, Ovid wrote:

Got all the above.  And basically understood it already.

> > I ask because I'm having some issues using the values in a (faked)
> > switch 
> > construct.
> > 
> > $_ = typeofcust($username, $password);
> > 
> > CASE: {
> > 
> >    /1/ and do { ... ;
> > 	last CASE; };
> >    /2/ and do { ... ;
> > 	last CASE; };
> >    /3/ and do { ... ;
> > 	last CASE; }
> >    blow_chunks;
> > 
> > }
> > 
> > If typeofcust() returns a value from 1, 2 or 3 is $_ treated as a
> > string
> > or number by the match operation?


> In this case, because you're using a regular expression, the $_ is
                                       ^^^^^^^^^^^^^^^^^^
Damn I should have known/remembered this.

> automatically treated as a string (regexes do not operate on numbers). 
> I might, however, add a "local" statement to the assignment:
> 
>   local $_ = typeofcust($username, $password);

This is OK inside of the main context?

> If you don't do that and any other place in your code is using $_, you
> just altered their value.  That can be a nasty bug to track down.
> 
> Also, check out Switch.pm
> (http://search.cpan.org/~dconway/Switch-2.09/Switch.pm).  It's more
> robust:

Geez.  I never think of CPAN when I've seen good code ie. from an animal
book author.  But I guess I can accept code from Damian.
   Well this should clean up my act a bit.  Thanks

>   use Switch;
> 
>   switch ($val) {
>     case 1          { print "number 1" }
>     case "a"        { print "string a" }
>     case [1..10,42] { print "number in list" }
>     case (@array)   { print "number in list" }
>     case /\w+/      { print "pattern" }
>     case qr/\w+/    { print "pattern" }
>     case (%hash)    { print "entry in hash" }
>     case (\%hash)   { print "entry in hash" }
>     case (\&sub)    { print "arg to subroutine" }
>     else            { print "previous case not true" }
>   }


Rod
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