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Is it possible to pass a subroutine to another subroutine?

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Join Date: Feb 2008

Posts: 28

Reputation: klactose is an unknown quantity at this point

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klactose

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Is it possible to pass a subroutine to another subroutine?

Sep 15th, 2008

Hello,

I am writing some testing scripts. At the end of each test I may have to return my environment back to it's default state using various subroutines in various modules. I realize that using the END block I can run these subroutines, however I have hundreds of these test to write and there is various formatting, etc, that is repetitious... so I want to include a single function in my END block that will accept other functions as parameters and then be able to run them from within itself.

A simple example would be:

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 perl Syntax (Toggle Plain Text) 
sub function_runner {
my @exit_functions = @_;
my $counter = 1;
foreach &function (@exit_functions) {
print "Performing exit function $counter:\n"; $counter++;
&function;
}
print "\nAll exit functions completed.\n";
}
sub function_runner {
my @exit_functions = @_;
my $counter = 1;
foreach &function (@exit_functions) {
print "Performing exit function $counter:\n"; $counter++;
&function;
}
print "\nAll exit functions completed.\n";
}

I realize this will not work as is, but the gist of what I am trying do is to be able to have function_runner(function1, function2, function3, etc) in my end block. Any help point me in the right direction would be greatly appreciated.

Thanks!

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Join Date: Mar 2006

Posts: 898

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KevinADC

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Re: Is it possible to pass a subroutine to another subroutine?

Sep 16th, 2008

You could try using a reference to a function.

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 Perl Syntax (Toggle Plain Text) 
sub some_function {
   print "foo";
}
 
my $some_function = \&some_function;
sub some_function {
   print "foo";
}

my $some_function = \&some_function;

You can pass $some_function like any other scalar, but you need to use the arrow operator to run the function.

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 Perl Syntax (Toggle Plain Text) 
$some_function->()
$some_function->()

Assuming you pass references to functions to your sub rotuine:

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 Perl Syntax (Toggle Plain Text) 
sub function_runner {
   my @exit_functions = @_;
   my $counter = 1;
   foreach my $function (@exit_functions) {
      print "Performing exit function $counter:\n";
      $counter++;
      $function->();
   }
   print "\nAll exit functions completed.\n";
}
sub function_runner {
   my @exit_functions = @_;
   my $counter = 1;
   foreach my $function (@exit_functions) {
      print "Performing exit function $counter:\n";
      $counter++;
      $function->();
   }
   print "\nAll exit functions completed.\n";
}