NAME
Sub::Fp - A Clojure / Python Toolz / Lodash inspired Functional Utility Library
VERSION
Version 0.02
SYNOPSIS
This library provides numerous functional programming utility methods, as well as functional varients of native in-built methods, to allow for consistent, concise code.
SUBROUTINES/METHODS
incr
Increments the supplied number by 1
incr(1)
# => 2decr
Decrements the supplied number by 1
decr(2)
# => 1maps
Creates an array of values by running each element in collection thru iteratee. The iteratee is invoked with three arguments: (value, index|key, collection).
maps(sub {
my $num = shift;
return $num + 1;
}, [1,1,1]);
# [2,2,2]reduces
Reduces collection to a value which is the accumulated result of running each element in collection thru iteratee, where each successive invocation is supplied the return value of the previous. If accumulator is not given, the first element of collection is used as the initial value. The iteratee is invoked with four arguments: (accumulator, value, index|key, collection).
# Implicit Accumulator
reduces(sub {
my ($sum, $num) = @_;
return $sum + $num;
}, [1,1,1]);
# 3
# Explict Accumulator
reduces(sub {
my ($accum, $num) = @_;
return {
%{ $accum },
key => $num,
}
}, {}, [1,2,3]);
# {
# key => 1,
# key => 2,
# key => 3,
# }flatten
Flattens array a single level deep.
flatten([1,1,1, [2,2,2]]);
# [1,1,1,2,2,2];drop
Creates a slice of array with n elements dropped from the beginning.
drop([1,2,3])
# [2,3];
drop(2, [1,2,3])
# [3]
drop(5, [1,2,3])
# []
drop(0, [1,2,3])
# [1,2,3]drop_right
Creates a slice of array with n elements dropped from the end.
drop_right([1,2,3]);
# [1,2]
drop_right(2, [1,2,3])
# [1]
drop_right(5, [1,2,3])
# []
drop_right(0, [1,2,3])
#[1,2,3]take
Creates a slice of array with n elements taken from the beginning.
take([1, 2, 3);
# [1]
take(2, [1, 2, 3]);
# [1, 2]
take(5, [1, 2, 3]);
# [1, 2, 3]
take(0, [1, 2, 3]);
# []take_right
Creates a slice of array with n elements taken from the end.
take_right([1, 2, 3]);
# [3]
take_right(2, [1, 2, 3]);
# [2, 3]
take_right(5, [1, 2, 3]);
# [1, 2, 3]
take_right(0, [1, 2, 3]);
# []first
Returns the first item in an array
first(["I", "am", "a", "string"])
# "I"
first([5,4,3,2,1])
# 5end
Returns the end, or last item in an array
end(["I", "am", "a", "string"])
# "string"
end([5,4,3,2,1])
# 1len
Returns the length of the collection. If an array, returns the number of items. If a hash, the number of key-val pairs. If a string, the number of chars (following built-in split)
len([1,2,3,4])
# 4
len("Hello")
# 5
len({ key => 'val', key2 => 'val'})
#2
len([])
# 0noop
A function that does nothing (like our government), and returns undef
noop()
# undefidentity
A function that returns its first argument
identity()
# undef
identity(1)
# 1
# identity([1,2,3])
# [1,2,3]is_array
Returns 0 or 1 if the argument is an array
is_array()
# 0
is_array([1,2,3])
# 1is_hash
Returns 0 or 1 if the argument is a hash
is_hash()
# 0
is_hash({ key => 'val' })
# 1spread
Destructures an array / hash into non-ref context. Destructures a string into an array of chars (following in-built split)
spread([1,2,3,4])
# 1,2,3,4
spread({ key => 'val' })
# key,'val'
spread("Hello")
# 'H','e','l','l','o'bool
Returns 0 or 1 based on truthiness of argument, following internal perl rules based on ternary coercion
bool([])
# 1
bool("hello!")
# 1
bool()
# 0
bool(undef)
# 0to_keys
Creates an array of the key names in a hash, indicies of an array, or chars in a string
to_keys([1,2,3])
# [0,1,2]
to_keys({ key => 'val', key2 => 'val2' })
# ['key', 'key2']
to_keys("Hey")
# [0, 1, 2];to_vals
Creates an array of the values in a hash, of an array, or string.
to_vals([1,2,3])
# [0,1,2]
to_vals({ key => 'val', key2 => 'val2' })
# ['val', 'val2']
to_vals("Hey");
# ['H','e','y'];uniq
Creates a duplicate-free version of an array, in which only the first occurrence of each element is kept. The order of result values is determined by the order they occur in the array.
uniq([2,1,2])
# [2,1]
uniq(["Hi", "Howdy", "Hi"])
# ["Hi", "Howdy"]assoc
Returns new hash, or array, with the updated value at index / key. Shallow updates only
assoc([1,2,3,4,5,6,7], 0, "item")
# ["item",2,3,4,5,6,7]
assoc({ name => 'sally', age => 26}, 'name', 'jimmy')
# { name => 'jimmy', age => 26}subarray
Returns a subset of the original array, based on start index (inclusive) and end idx (not-inclusive)
subarray(["first", "second", "third", "fourth"], 0,2)
# ["first", "second"]find
Iterates over elements of collection, returning the first element predicate returns truthy for.
my $people = [
{
name => 'john',
age => 25,
},
{
name => 'Sally',
age => 25,
}
]
find(sub {
my $person = shift;
return equal($person->{'name'}, 'sally')
}, $people);
# { name => 'sally', age => 25 }filter
Iterates over elements of collection, returning only elements the predicate returns truthy for.
my $people = [
{
name => 'john',
age => 25,
},
{
name => 'Sally',
age => 25,
},
{
name => 'Old Greg',
age => 100,
}
]
filter(sub {
my $person = shift;
return $person->{'age'} < 30;
}, $people);
# [
# {
# name => 'john',
# age => 25,
# },
# {
# name => 'Sally',
# age => 25,
# }
# ]none
If one element is found to return truthy for the given predicate, none returns 0
my $people = [
{
name => 'john',
age => 25,
},
{
name => 'Sally',
age => 25,
},
{
name => 'Old Greg',
age => 100,
}
]
none(sub {
my $person = shift;
return $person->{'age'} > 99;
}, $people);
# 0
none(sub {
my $person = shift;
return $person->{'age'} > 101;
}, $people);
# 1every
Itterates through each element in the collection, and checks if element makes predicate return truthy. If all elements cause predicate to return truthy, every returns 1;
every(sub {
my $num = shift;
$num > 0;
}, [1,2,3,4]);
# 1
every(sub {
my $num = shift;
$num > 2;
}, [1,2,3,4]);
# 0some
Checks if predicate returns truthy for any element of collection. Iteration is stopped once predicate returns truthy.
some(sub {
my $num = shift;
$num > 0;
}, [1,2,3,4]);
# 1
some(sub {
my $num = shift;
$num > 2;
}, [1,2,3,4]);
# 1partial
Creates a function that invokes func with partials prepended to the arguments it receives. (funcRef, args)
my $add_three_nums = sub {
my ($a, $b, $c) = @_;
return $a + $b + $c;
};
my $add_two_nums = partial($add_three_nums, 1);
$add_two_nums->(1,1)
# 3
# Can also use __ to act as a placeholder
my $add_four_strings = sub {
my ($a, $b, $c, $d) = @_;
return $a . $b . $c . $d;
};
my $add_two_strings = partial($add_four_strings, "first ", __, "third ", __);
$add_two_strings->("second ", "third ")
# "first second third fourth"chain
Composes functions, left to right, and invokes them, returning the result. Accepts an expression as the first argument, to be passed as the first argument to the proceding function
chain(
[1,2,3, [4,5,6]],
sub {
my $array = shift;
return [spread($array), 7]
},
\&flatten,
);
# [1,2,3,4,5,6,7]
# Invokes first function, and uses that as start value for next func
chain(
sub { [1,2,3, [4,5,6]] },
sub {
my $array = shift;
return [spread($array), 7]
},
\&flatten,
)
# [1,2,3,4,5,6,7]EXPORT
A list of functions that can be exported. You can delete this section if you don't export anything, such as for a purely object-oriented module.
incr reduces flatten
drop_right drop take_right take
assoc maps decr chain
first end subarray partial
__ find filter some
none uniq bool spread
len to_keys to_vals is_array
is_hash every noop identityAUTHOR
Kristopher C. Paulsen, <kristopherpaulsen+cpan at gmail.com>
BUGS
Please report any bugs or feature requests to bug-sub-fp at rt.cpan.org, or through the web interface at https://rt.cpan.org/NoAuth/ReportBug.html?Queue=Sub-Fp. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.
SUPPORT
You can find documentation for this module with the perldoc command.
perldoc Sub::FpYou can also look for information at:
RT: CPAN's request tracker (report bugs here)
AnnoCPAN: Annotated CPAN documentation
CPAN Ratings
Search CPAN
ACKNOWLEDGEMENTS
LICENSE AND COPYRIGHT
Copyright 2018 Kristopher C. Paulsen.
This program is free software; you can redistribute it and/or modify it under the terms of the the Artistic License (2.0). You may obtain a copy of the full license at:
http://www.perlfoundation.org/artistic_license_2_0
Any use, modification, and distribution of the Standard or Modified Versions is governed by this Artistic License. By using, modifying or distributing the Package, you accept this license. Do not use, modify, or distribute the Package, if you do not accept this license.
If your Modified Version has been derived from a Modified Version made by someone other than you, you are nevertheless required to ensure that your Modified Version complies with the requirements of this license.
This license does not grant you the right to use any trademark, service mark, tradename, or logo of the Copyright Holder.
This license includes the non-exclusive, worldwide, free-of-charge patent license to make, have made, use, offer to sell, sell, import and otherwise transfer the Package with respect to any patent claims licensable by the Copyright Holder that are necessarily infringed by the Package. If you institute patent litigation (including a cross-claim or counterclaim) against any party alleging that the Package constitutes direct or contributory patent infringement, then this Artistic License to you shall terminate on the date that such litigation is filed.
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