Declare::Constraints::UserlDeclare::Constraints::Simple::Library::Operators(3)NAMEDeclare::Constraints::Simple::Library::Operators - Operators
SYNOPSIS
# all hast to be valid
my $and_constraint = And( IsInt,
Matches(qr/0$/) );
# at least one has to be valid
my $or_constraint = Or( IsInt, HasLength );
# only one can be valid
my $xor_constraint = XOr( IsClass, IsObject );
# reverse validity
my $not_an_integer = Not( IsInt );
# case valid, validate 'bar' key depending on 'foo' keys value
my $struct_prof =
And( IsHashRef,
CaseValid( OnHashKeys(foo => IsEq("FooArray")),
OnHashKeys(bar => IsArrayRef),
OnHashKeys(foo => IsEq("FooHash")),
OnHashKeys(bar => IsHashRef) ));
DESCRIPTION
This module contains the frameworks operators. These constraint like
elements act on the validity of passed constraints.
OPERATORS
And(@constraints)
Is true if all passed @constraints are true on the value. Returns the
result of the first failing constraint.
Or(@constraints)
Is true if at least one of the passed @contraints is true. Returns the
last failing constraint's result if false.
XOr(@constraints)
Valid only if a single one of the passed @constraints is valid. Returns
the last failing constraint's result if false.
Not($constraint)
This is valid if the passed $constraint is false. The main purpose of
this operator is to allow the easy reversion of a constraint's
trueness.
CaseValid($test, $conseq, $test2, $conseq2, ...)
This runs every given $test argument on the value, until it finds one
that returns true. If none is found, false is returned. On a true
result, howver, the corresponding $conseq constraint is applied to the
value and it's result returned. This allows validation depending on
other properties of the value:
my $flexible = CaseValid( IsArrayRef,
And( HasArraySize(1,5),
OnArrayElements(0 => IsInt) ),
IsHashRef,
And( HasHashElements(qw( head tail )),
OnHashKeys(head => IsInt) ));
Of course, you could model most of it probably with the other
operators, but this is a bit more readable. For default cases use
"ReturnTrue" from Declare::Constraints::Simple::Library::General as
test.
SEE ALSO
Declare::Constraints::Simple, Declare::Constraints::Simple::Library
AUTHOR
Robert 'phaylon' Sedlacek "<phaylon@dunkelheit.at>"
LICENSE AND COPYRIGHT
This module is free software, you can redistribute it and/or modify it
under the same terms as perl itself.
perl v5.14.1Declare::Constraints::Simple::Library::Operators(3)
