The value is valid if the value is an array reference. The contents of
the array can be validated by passing an other $constraint as
The stack or path part of IsArrayRef is IsArrayRef[$index] where
$index is the index of the failing element.
IsHashRef(-keys => CW$constraint, -values => CW$constraint)
True if the value is a hash reference. It can also take two named
parameters: -keys can pass a constraint to check the hashes keys,
-values does the same for its values.
The stack or path part of IsHashRef looks like
IsHashRef[$type $key] where $type is either val or key
depending on what was validated, and $key being the key that didnt
Code references have to be valid to pass this constraint.
True if the value is a regular expression built with qr. <B>NoteB>
however, that a simple string that could be used like /$rx/ will
not pass this constraint. You can combine multiple constraints with