Question

I’m using a config file (in YAML) to define types that are used later on to validate other config values required for my app:

---
action: >
        use List::MoreUtils;
        my $value = $_;
        any { $value eq $_ } qw(fatal keep merge non-fatal replace);
dir   : return defined $_ ? -d $_ : -1;
file  : return defined $_ ? -f $_ : -1;
string: 1;


---
config-element:
    value: foo
    type : file
etc ...

The idea is to eval each type definition, throw them into a hash and then call to validate configuration data (the following is schematic for easy comprehensibility):

#throw sub refs into hash
my %type_sub;
foreach my $key (keys %$type_def_ref) {
    my $sub_str = "sub {$type_def_ref->{$key}}";
    $type_sub{$key} = eval $sub_str;

}

#validate (myfile is a real file in the cwd)
print $type_sub{file}->('myfile'),"\n";
print $type_sub{action}->('fatal'), "\n";

The problem is that the subroutines in %type_sub don’t seem to accept parameters. In the above case, the first print statement outputs -1 while the second outputs:

Use of uninitialized value $value in string eq at (eval 15) line 1.
Use of uninitialized value $_ in string eq at (eval 15) line 1.
Can't call method "any" without a package or object reference at 
(eval 15) line 1.

which is not at all what I expect, yet the subroutines are being called.

What am I doing wrong?

EDIT:
I was being sloppy and everything works fine now. Thanks to Friedo.

Answer 1

Your subroutine parameters will be in the @_ array, not $_. To get the first parameter, look in $_[0] or do my $foo = shift;. (shift operates on @_ by default.)

As for any, I believe the problem is due to any not being able to load its prototype at runtime (subroutine prototypes can only be called at compile-time.) You may need to use explicit parens and an explicit subroutine reference:

any( sub { $value eq $_ }, qw(fatal keep merge non-fatal replace) );