# man > Type::Tiny::Manual::Optimization

## NAME
    [Type::Tiny::Manual::Optimization](https://www.chedong.com/phpMan.php/perldoc/Type%3A%3ATiny%3A%3AManual%3A%3AOptimization/markdown) - squeeze the most out of your CPU

## MANUAL
    [Type::Tiny](https://www.chedong.com/phpMan.php/perldoc/Type%3A%3ATiny/markdown) is written with efficiency in mind, but there are techniques you can use to get the
    best performance out of it.

  XS
    The simplest thing you can do to increase performance of many of the built-in type constraints
    is to install [Type::Tiny::XS](https://www.chedong.com/phpMan.php/perldoc/Type%3A%3ATiny%3A%3AXS/markdown), a set of ultra-fast type constraint checks implemented in C.

    [Type::Tiny](https://www.chedong.com/phpMan.php/perldoc/Type%3A%3ATiny/markdown) will attempt to load [Type::Tiny::XS](https://www.chedong.com/phpMan.php/perldoc/Type%3A%3ATiny%3A%3AXS/markdown) and use its type checks. If [Type::Tiny::XS](https://www.chedong.com/phpMan.php/perldoc/Type%3A%3ATiny%3A%3AXS/markdown) is not
    available, it will then try to use Mouse *if it is already loaded*, but [Type::Tiny](https://www.chedong.com/phpMan.php/perldoc/Type%3A%3ATiny/markdown) won't attempt
    to load Mouse for you.

    Certain type constraints can also be accelerated if you have [Ref::Util::XS](https://www.chedong.com/phpMan.php/perldoc/Ref%3A%3AUtil%3A%3AXS/markdown) installed.

   Types that can be accelerated by [Type::Tiny::XS](https://www.chedong.com/phpMan.php/perldoc/Type%3A%3ATiny%3A%3AXS/markdown)
    The following simple type constraints from [Types::Standard](https://www.chedong.com/phpMan.php/perldoc/Types%3A%3AStandard/markdown) will be accelerated by
    [Type::Tiny::XS](https://www.chedong.com/phpMan.php/perldoc/Type%3A%3ATiny%3A%3AXS/markdown): Any, ArrayRef, Bool, ClassName, CodeRef, Defined, FileHandle, GlobRef, HashRef,
    Int, Item, Object, Map, Ref, ScalarRef, Str, Tuple, Undef, and Value. (Note that Num and
    RegexpRef are *not* on that list.)

    The parameterized form of Ref cannot be accelerated.

    The parameterized forms of ArrayRef, HashRef, and Map can be accelerated only if their
    parameters are.

    The parameterized form of Tuple can be accelerated if its parameters are, it has no Optional
    components, and it does not use "slurpy".

    Certain type constraints may benefit partially from [Type::Tiny::XS](https://www.chedong.com/phpMan.php/perldoc/Type%3A%3ATiny%3A%3AXS/markdown). For example, RoleName
    inherits from ClassName, so part of the type check will be conducted by [Type::Tiny::XS](https://www.chedong.com/phpMan.php/perldoc/Type%3A%3ATiny%3A%3AXS/markdown).

    The parameterized InstanceOf, HasMethods, and Enum type constraints will be accelerated. So will
    [Type::Tiny::Class](https://www.chedong.com/phpMan.php/perldoc/Type%3A%3ATiny%3A%3AClass/markdown), [Type::Tiny::Duck](https://www.chedong.com/phpMan.php/perldoc/Type%3A%3ATiny%3A%3ADuck/markdown), and [Type::Tiny::Enum](https://www.chedong.com/phpMan.php/perldoc/Type%3A%3ATiny%3A%3AEnum/markdown) objects.

    The PositiveInt and PositiveOrZeroInt type constraints from [Types::Common::Numeric](https://www.chedong.com/phpMan.php/perldoc/Types%3A%3ACommon%3A%3ANumeric/markdown) will be
    accelerated, as will the NonEmptyStr type constraint from [Types::Common::String](https://www.chedong.com/phpMan.php/perldoc/Types%3A%3ACommon%3A%3AString/markdown).

    The StringLike, CodeLike, HashLike, and ArrayLike types from [Types::TypeTiny](https://www.chedong.com/phpMan.php/perldoc/Types%3A%3ATypeTiny/markdown) will be
    accelerated, but parameterized HashLike and ArrayLike will not.

    [Type::Tiny::Union](https://www.chedong.com/phpMan.php/perldoc/Type%3A%3ATiny%3A%3AUnion/markdown) and [Type::Tiny::Intersection](https://www.chedong.com/phpMan.php/perldoc/Type%3A%3ATiny%3A%3AIntersection/markdown) will also be accelerated if their constituent
    type constraints are.

   Types that can be accelerated by Mouse
    The following simple type constraints from [Types::Standard](https://www.chedong.com/phpMan.php/perldoc/Types%3A%3AStandard/markdown) will be accelerated by
    [Type::Tiny::XS](https://www.chedong.com/phpMan.php/perldoc/Type%3A%3ATiny%3A%3AXS/markdown): Any, ArrayRef, Bool, ClassName, CodeRef, Defined, FileHandle, GlobRef, HashRef,
    Ref, ScalarRef, Str, Undef, and Value. (Note that Item, Num, Int, Object, and RegexpRef are
    *not* on that list.)

    The parameterized form of Ref cannot be accelerated.

    The parameterized forms of ArrayRef and HashRef can be accelerated only if their parameters are.

    Certain type constraints may benefit partially from Mouse. For example, RoleName inherits from
    ClassName, so part of the type check will be conducted by Mouse.

    The parameterized InstanceOf and HasMethods type constraints will be accelerated. So will
    [Type::Tiny::Class](https://www.chedong.com/phpMan.php/perldoc/Type%3A%3ATiny%3A%3AClass/markdown) and [Type::Tiny::Duck](https://www.chedong.com/phpMan.php/perldoc/Type%3A%3ATiny%3A%3ADuck/markdown) objects.

### Inlining Type Constraints
    In the case of a type constraint like this:

     my $type = Int->where(sub { $_ >= 0 });

    [Type::Tiny](https://www.chedong.com/phpMan.php/perldoc/Type%3A%3ATiny/markdown) will need to call one sub to verify a value meets the Int type constraint, and your
    coderef to check that the value is above zero.

    Sub calls in Perl are relatively expensive in terms of memory and CPU usage, so it would be good
    if it could be done all in one sub call.

    The Int type constraint knows how to create a string of Perl code that checks an integer. It's
    something like the following. (It's actually more complicated, but this is close enough as an
    example.)

     $_ =~ /^-?[0-9]+$/

    If you provide your check as a string instead of a coderef, like this:

     my $type = Int->where(q{ $_ >= 0 });

    Then [Type::Tiny](https://www.chedong.com/phpMan.php/perldoc/Type%3A%3ATiny/markdown) will be able to combine them into one string:

     ( $_ =~ /^-?[0-9]+$/ ) && ( $_ >= 0 )

    So [Type::Tiny](https://www.chedong.com/phpMan.php/perldoc/Type%3A%3ATiny/markdown) will be able to check values in one sub call. Providing constraints as strings is
    a really simple and easy way of optimizing type checks.

    But it can be made even more efficient. [Type::Tiny](https://www.chedong.com/phpMan.php/perldoc/Type%3A%3ATiny/markdown) needs to localize $_ and copy the value into
    it for the above check. If you're checking ArrayRef[$type] this will be done for each element of
    the array. Things could be made more efficient if [Type::Tiny](https://www.chedong.com/phpMan.php/perldoc/Type%3A%3ATiny/markdown) were able to directly check:

     ( $arrayref->[$i] =~ /^-?[0-9]+$/ ) && ( $arrayref->[$i] >= 0 )

    This can be done by providing an inlining sub. The sub is given a variable name and can use that
    in the string of code it generates.

     my $type = [Type::Tiny](https://www.chedong.com/phpMan.php/perldoc/Type%3A%3ATiny/markdown)->new(
       parent  => Int,
       inlined => sub {
         my ($self, $varname) = @_;
         return sprintf(
           '(%s) && ( %s >= 0 )',
           $self->parent->inline_check($varname),
           $varname,
         );
       }
     );

    Because it's pretty common to want to call your parent's inline check and "&&" your own string
    with it, [Type::Tiny](https://www.chedong.com/phpMan.php/perldoc/Type%3A%3ATiny/markdown) provides a shortcut for this. Just return a list of strings to smush
    together with "&&", and if the first one is "undef", [Type::Tiny](https://www.chedong.com/phpMan.php/perldoc/Type%3A%3ATiny/markdown) will fill in the blank with the
    parent type check.

     my $type = [Type::Tiny](https://www.chedong.com/phpMan.php/perldoc/Type%3A%3ATiny/markdown)->new(
       parent  => Int,
       inlined => sub {
         my ($self, $varname) = @_;
         return (
           undef,
           sprintf('%s >= 0', $varname),
         );
       }
     );

    There is one further optimization which can be applied to this particular case. You'll note that
    we're checking the string matches "/^-?[0-9+]$/" and then checking it's greater than or equal to
    zero. But a non-negative integer won't ever start with a minus sign, so we could inline the
    check to something like:

     $_ =~ /^[0-9]+$/

    While an inlined check *can* call its parent type check, it is not required to.

     my $type = [Type::Tiny](https://www.chedong.com/phpMan.php/perldoc/Type%3A%3ATiny/markdown)->new(
       parent  => Int,
       inlined => sub {
         my ($self, $varname) = @_;
         return sprintf('%s =~ /^[0-9]+$/', $varname);
       }
     );

    If you opt not to call the parent type check, then you need to ensure your own check is at least
    as rigorous.

### Inlining Coercions
    Moo is the only object-oriented programming toolkit that fully supports coercions being inlined,
    but even for Moose and Mouse, providing coercions as strings can help [Type::Tiny](https://www.chedong.com/phpMan.php/perldoc/Type%3A%3ATiny/markdown) optimize its
    coercion features.

    For Moo, if you want your coercion to be inlinable, all the types you're coercing from and to
    need to be inlinable, plus the coercion needs to be given as a string of Perl code.

### Common Sense
    The HashRef[ArrayRef] type constraint can probably be checked faster than
    HashRef[ArrayRef[Num]]. If you find yourself using very complex and slow type constraints, you
    should consider switching to simpler and faster ones. (Though this means you have to place a
    little more trust in your caller to not supply you with bad data.)

    (A counter-intuitive exception to this: even though Int is more restrictive than Num, in most
    circumstances Int checks will run faster.)

### [Devel::StrictMode](https://www.chedong.com/phpMan.php/perldoc/Devel%3A%3AStrictMode/markdown)
    One possibility is to use strict type checks when you're running your release tests, and faster,
    more permissive type checks at other times. [Devel::StrictMode](https://www.chedong.com/phpMan.php/perldoc/Devel%3A%3AStrictMode/markdown) can make this easier.

    This provides a "STRICT" constant that indicates whether your code is operating in "strict mode"
    based on certain environment variables.

   Attributes
     use [Types::Standard](https://www.chedong.com/phpMan.php/perldoc/Types%3A%3AStandard/markdown) qw( ArrayRef Num );
     use [Devel::StrictMode](https://www.chedong.com/phpMan.php/perldoc/Devel%3A%3AStrictMode/markdown) qw( STRICT );

     has numbers => (
       is      => 'ro',
       isa     => STRICT ? ArrayRef[Num] : ArrayRef,
       default => sub { [] },
     );

    It is inadvisible to do this on attributes that have coercions because it can lead to
    inconsistent and unpredictable behaviour.

   [Type::Params](https://www.chedong.com/phpMan.php/perldoc/Type%3A%3AParams/markdown)
     use [Types::Standard](https://www.chedong.com/phpMan.php/perldoc/Types%3A%3AStandard/markdown) qw( Num Object );
     use [Type::Params](https://www.chedong.com/phpMan.php/perldoc/Type%3A%3AParams/markdown) qw( compile );
     use [Devel::StrictMode](https://www.chedong.com/phpMan.php/perldoc/Devel%3A%3AStrictMode/markdown) qw( STRICT );

     sub add_number {
       state $check;
       $check = compile(Object, Num) if STRICT;

       my ($self, $num) = STRICT ? $check->(@_) : @_;
       push @{ $self->numbers }, $num;
       return $self;
     }

    Again, you need to be careful to ensure consistent behaviour if you're using coercions,
    defaults, slurpies, etc.

   Ad-Hoc Type Checks
     ...;
     my $x = get_some_number();
     assert_Int($x) if STRICT;
     return $x + 1;
     ...;

## NEXT STEPS
    Here's your next step:

    *   [Type::Tiny::Manual::Coercions](https://www.chedong.com/phpMan.php/perldoc/Type%3A%3ATiny%3A%3AManual%3A%3ACoercions/markdown)

        Advanced information on coercions.

## AUTHOR
    Toby Inkster <<tobyink@cpan.org>>.

## COPYRIGHT AND LICENCE
    This software is copyright (c) 2013-2014, 2017-2021 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.

## DISCLAIMER OF WARRANTIES
    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.