Call a perl module's method from a string

Question

Given a perl module Foo.pm with methods aSub() and bSub()

my $obj = Foo->new();
my $x = $obj->aSub($argA);
my $y = $obj->bSub($argB);

I have a TAP program where I build an array of hashes:

my $test_case = [
   'aSub' => "foobar",
   'bSub' => "whobar"
];

I would like to be able to parse the array and use the key/value elements to call methods on the Foo object $obj;
Like a static method:

if ($key eq 'aSub') {
  $obj->aSub($value)
} elsif ($key eq 'bSub') {
  $obj->bSub($value);
}
...

I would prefer to do this polymorphically so I don't have to hard code the methods:

$obj->{$key}($value) #or something of the sort

I have tried several methods using references and/or glob, but I keep on getting an error:

Error: Threw an exception: aSub is not defined

Test::Harness capturing the error and printing less useful message?

$test_case as you defined it is not an array of hashes, it's just an array of strings (it's the same as $test_case = [qw(aSub foobar bSub whobar)]). — cjm
– cjm, Commented Jun 8, 2011 at 23:45
very good. My actual array looks like [<scalar>, <hash>, <scalar>..]. My everything was looking like a scalar to my test, so it was never reaching the proper point. The exception/error must be getting thrown by the module Foo that is trying to interpret 'aSub' as a valid argument to $obj->bSub($target); — MEH
– MEH, Commented Jun 9, 2011 at 0:22

cjm · Accepted Answer · 2011-06-08 23:42:34Z

15

Calling a method whose name is in a variable is easy:

my $key = 'aSub';
my $value = 'foobar';
my $obj = Foo->new();

$obj->$key($value);

answered Jun 8, 2011 at 23:42

cjm

62.2k9 gold badges133 silver badges179 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

This is correct, though the source of the error was really in my data structure. Since you pointed that out as well, I think you deserve the win.