How can I pass parameters to Perl subroutines defined using eval?

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'),"
"; print $type_sub{action}->('fatal'), "
"; ``` 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…

Accepted Answer

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) );
```

How can I pass parameters to Perl subroutines defined using eval?

Solution

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