How do you code a subtype definition that forces a coercion to be used?
I have:
package My::Types;
use MooseX::Types -declare => [ qw( A chA nochA ) ];
sub _valid_A {
my $val = shift;
$val =~ /^(?:chr)A/
}
subtype A,
as Str,
where { _valid_A($_) };
subtype chrA;
coerce chrA, from A, via { s/^(?!chr)/chr/; $_ };
subtype nochA;
coerce nochrA, from A, via { s/^chr//; $_ };
Written that way, I get it dying:
MooseX::Types::TypeDecorator::AUTOLOAD(): Method 'create_child_type' is not
supported for ...
If I change the target subtypes to have an "as Str" clause, it no longer dies
but it accepts any string without appliying the coercion. The same happens if
I use "as A".
So, how do I specify a type that starts with a base type, but then applies a
coercion? All the examples I see of coercions have a "natural" base encoding,
with the coercion providing a way to take some other type of value and turn it
into the base - but when base is a validated string, it is hard to get it to
actually use the coercion.
John Macdonald
Software Engineer
Ontario Institute for Cancer Research
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