NAME
Sub::Operable - apply Perl built-in operators to coderefs
SYNOPSIS
use Sub::Operable 'subop';
# f(x) = x²
#
my $f = subop { $_ ** 2 };
# f(4) = 4²
# = 16
#
say $f->(4); # ==> 16
# g(x) = 2x
#
my $g = subop { 2 ** $_ };
# h = f + g + 3
#
my $h = $f + $g + 3;
# h(10) = f(10) + g(10) + 3
# = 10² + 2(10) + 3
# = 100 + 20 + 3
# = 123
#
say $h->(10); # ==> 123
DESCRIPTION
Sub::Operator allows you to define functions and apply operations to the
functions like you can in algebra class.
All the standard built-in binary, string, numeric, and comparison
operators should work fine. Operators like `+=` which mutate their
operands are not supported.
Additionally if you call a Sub::Operator-enabled function passing another
Sub::Operator-enabled function as an argument, you get a composed
Sub::Operator-enabled function as the result.
# Assume $f and $g defined as above.
# m(x) = g( f(x) )
#
my $m = $g->( $f );
# m(10) = g( f(10) )
# = g( 10² )
# = g( 100 )
# = 2 * 100
# = 200
#
say $m->(10); # ==> 200
Object-Oriented Constructor
use Sub::Operable;
my $coderef = 'Sub::Operable'->new(sub { ... });
When the coderefs are called, $_ will be an alias of $_[0].
Shortcut Constructor
use Sub::Operable qw( subop );
my $coderef = subop { ... };
When the coderefs are called, $_ will be an alias of $_[0].
Utility Function
use Sub::Operable qw( isa_Sub_Operable );
my $bool = isa_Sub_Operable( $coderef );
Constants
You can get lists of supported operators:
use Sub::Operable;
my @prefix = Sub::Operable::PREFIX_OPS;
my @infix = Sub::Operable::INFIX_OPS;
Symbol Table Frickery
You don't have to just deal with coderefs. You can put these functions
into the symbol table.
use Sub::Operable 'subop';
# f(x) = x²
#
*f = subop { $_ ** 2 };
# f(4) = 4²
# = 16
#
say f(4); # ==> 16
# g(x) = 2x
#
*g = subop { 2 ** $_ };
# h = f + g + 3
#
*h = \&f + \&g + 3;
# h(10) = f(10) + g(10) + 3
# = 10² + 2(10) + 3
# = 100 + 20 + 3
# = 123
#
say h(10); # ==> 123
BUGS
Please report any bugs to
<
http://rt.cpan.org/Dist/Display.html?Queue=Sub-Operable>.
SEE ALSO
curry, I guess?
AUTHOR
Toby Inkster <
[email protected]>.
COPYRIGHT AND LICENCE
This software is copyright (c) 2020 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.
