ichimunki has asked for the wisdom of the Perl Monks concerning the following question:

The following is a generalization, but hopefully it's clear enough.

I have a two packages, Foo::Bar and Foo::Batz. I have a sub called Plop which will create an object in one of these packages, based on it's argument in the statement. But the following code fails me, with a "Bad Name after Package::" error. 
use strict;
require 'foo_bar.pl';  #currently using require for these
require 'foo_batz.pl'; #intention is to fold them into the 
                       #script after development 
my @Stack = ();
my $type = "Bar" || "Batz";
do_phu($type);

sub do_phu {
    my $class = shift;
    my $temp_obj = Foo::$type->new();
    push( @Stack, $temp_obj ); # point of failure
}

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The answer to this is probably right in front of my face, but I'm stuck. I know there must be an alternative that doesn't involve a lot of if-thens.

Thanks in advance for any help!

Replies are listed 'Best First'.
Re: Scalar in Method Call
by Fastolfe (Vicar) on Dec 22, 2000 at 09:29 UTC
    I suspect it's complaining about your use of a variable within the module identifier (Foo::$type). The code there is ambiguous/bad. You probably want something like this (works in 5.6, not sure about earlier): 
    my $temp_obj = "Foo::$type"->new();

# or, a more verbose version:

no strict 'refs';    # because this isn't very strict
my $temp_obj = &{"Foo::${type}::new"}("Foo::$type");

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[select]
      Says fastolfe: 
      no strict 'refs';    # because this isn't very strict
my $temp_obj = "Foo::$type"->new();

      [download]
      The no strict 'refs' is unnecessary here, since you aren't dealing with references of any sort. The code will run just fine under strict refs.

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[d/l]
        You're right; it was the latter method that would have generated the error. I switched the order of the code around and neglected to move the 'no strict' with it.
[reply]
      Quoting the construct alleviated the error, on to the other bugs. Thanks!
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Re: Scalar in Method Call
by Anonymous Monk on Dec 23, 2000 at 01:56 UTC
    Here is the way I was shown, just put the module names into a hash reference: 
    
  use strict;
  require 'foo_bar.pl';  #currently using require for these
  require 'foo_batz.pl'; #intention is to fold them into the 
                         #script after development 

  my $mods = {
      'Bar'  => 'Foo::Bar',
      'Batz' => 'Foo::Batz',
  };
  my @Stack = ();
  my $type = "Bar" || "Batz";
  do_phu($type);

  sub do_phu {
      my $class = shift;
      my $temp_obj = $mods->{$type}->new();
      push( @Stack, $temp_obj ); # point of failure
  }

    [download]
[reply]
[d/l]

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