NAME
    Sub::Boolean - make XS true/false subs

SYNOPSIS
      use Test::More;
      use Sub::Boolean qw( make_true );
  
      make_true( __PACKAGE__ . "::foobar" );
  
      ok( foobar(),    'returns true' );
      ok( foobar(123), 'returns true' );

DESCRIPTION
    A good way to create fast true/false constants is:

      use constant { true => !!1, false => !!0 };

    Or on newer Perls:

      use builtin qw( true false );

    However these constants will throw a compile-time error if you call them
    as a sub:

      if ( true(123) ) {
        ...;
      }

    Sub::Boolean allows you to create subs which return true or false fast as
    they're implemented in XS.

    As a bonus, it can also generate subs which return undef or the empty
    list.

    Each function created by this module will have a different refaddr, which
    means that using things like `set_prototype` or `set_subname` on one will
    not affect others.

    Boolean functions are really unlikely to be a bottleneck in most
    applications, so the use cases for this module are very limited.

FUNCTIONS
    Nothing is exported unless requested.

  `make_true( $qualified_name )`
    Given a fully qualified sub name, installs a sub something like:

      sub $qualified_name {
        return !!1;
      }

    If called as `make_true()` with no name, returns an anonymous coderef.

  `make_false( $qualified_name )`
    Given a fully qualified sub name, installs a sub something like:

      sub $qualified_name {
        return !!0;
      }

    If called as `make_false()` with no name, returns an anonymous coderef.

  `make_undef( $qualified_name )`
    Given a fully qualified sub name, installs a sub something like:

      sub $qualified_name {
        return undef;
      }

    If called as `make_undef()` with no name, returns an anonymous coderef.

  `make_empty( $qualified_name )`
    Given a fully qualified sub name, installs a sub something like:

      sub $qualified_name {
        return ();
      }

    If called as `make_empty()` with no name, returns an anonymous coderef.

BUGS
    Please report any bugs to
    <https://github.com/tobyink/p5-sub-boolean/issues>.

SEE ALSO
    builtin, constant.

AUTHOR
    Toby Inkster <tobyink@cpan.org>.

COPYRIGHT AND LICENCE
    This software is copyright (c) 2022 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.

