Type::Tiny::Manual::NonOO − Type::Tiny in non−object−oriented code
Although Type::Tiny was designed with object-oriented programming in mind, especially Moose-style classes and roles, it can be used in procedural and imperative programming.
If you have read Type::Tiny::Manual::UsingWithMoo, you should understand how Type::Params can be used to validate method parameters. This same technique can be applied to regular subs too. More information about checking parameters can be found in Type::Tiny::Manual::Params.
The "is_*" and "assert_*" functions exported by type libraries may be useful in non-OO code too. See Type::Tiny::Manual::UsingWithMoo3.
Perl 5.10 introduced the smart match operator "˜˜", which has since been deprecated because though the general idea is fairly sound, the details were a bit messy.
Nevertheless, Type::Tiny has support for smart match and I’m documenting it here because there’s nowhere better to put it.
The following can be used as to check if a value passes a type constraint:
$value ˜˜ SomeType
Where it gets weird is if $value is an object and overloads "˜˜". Which overload of "˜˜" wins? I don’t know.
Better to use:
SomeType−>check(
$value ) # more reliable, probably faster
is_SomeType($value) # more reliable, definitely faster
It’s also possible to do:
$value ˜˜ SomeType−>coercion
This checks to see if $value matches any type that can be coerced to SomeType.
But better to use:
SomeType−>coercion−>has_coercion_for_value( $value )
Related to the smart match operator is the "given"/"when" syntax.
This will not do what you want it to do:
use
Types::Standard qw( Str Int );
given ($value) {
when (Int) { ... }
when (Str) { ... }
}
This will do what you wanted:
use
Types::Standard qw( is_Str is_Int );
given ($value) {
when (\&is_Int) { ... }
when (\&is_Str) { ... }
}
Sorry, that’s just how Perl be.
Better though:
use
Types::Standard qw( Str Int );
use Type::Utils qw( match_on_type );
match_on_type $value => (
Str, sub { ... },
Int, sub { ... },
);
If this is part of a loop or other frequently called bit of code, you can compile the checks once and use them many times:
use
Types::Standard qw( Str Int );
use Type::Utils qw( compile_match_on_type );
my $dispatch_table = compile_match_on_type(
Str, sub { ... },
Int, sub { ... },
);
$dispatch_table−>($_) for @lots_of_values;
As with most things in Type::Tiny, those coderefs can be replaced by strings of Perl code.
Here’s your next step:
• |
Type::Tiny::Manual::Optimization |
Squeeze the most out of your CPU.
Toby Inkster <[email protected]>.
This software is copyright (c) 2013−2014, 2017−2023 by Toby Inkster.
This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.
THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.