CODEWITHSUNDEEP
perlmoose
Bram Vanroy
Bram Vanroy

Reputation: 28465

Dynamically generate writer/reader from attribute names in Moose

In Moose we can put restrictions on instance attributes or add getters/setters like so:

has 'color' => (
  is  => 'rw',
  isa => 'Str',
  writer => '_set_color',
);

My question is, is there a way to do this dynamically for an array of elements? It's possible to do something like this:

has ['color', 'temperature', 'size'] => (
  is  => 'rw',
  isa => 'Str',
);

But is there a way to create for each of these items its own writer (or reader), e.g. _set_color, _set_temperature, _set_size? I tried to see if the following yielded any insight, but it returned an error

bad accessor/reader/writer/predicate/clearer format, must be a HASH ref

has ['color', 'temperature', 'size'] => (
  is  => 'rw',
  isa => 'Str',
  writer => sub {
    print Dumper(\@_);
    return;
);

What I am hoping to get is something like (which doesn't work):

has ['color', 'temperature', 'size'] => (
  is  => 'rw',
  isa => 'Str',
  writer => "_set_$_";
);

I need custom writers, so just going for the ones provided by Moose does not work for me.

Upvotes: 2

Views: 63

Answers (1)

Dave Cross
Dave Cross

Reputation: 69274

has isn't magic. It's just a subroutine call. So something like this should work (untested):

for (qw[colour temperature size]) {
  has $_ => (
    is     => 'rw',
    isa    => 'Str',
    writer => "_set_$_",
  );
}

Upvotes: 4

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