Functional programming library for Tarsana
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Streams New in version 1.1.0
Please use composer to install this library:
composer require tarsana/functional
The script I am using to generate the Reference Documentation files for this library is a good example of usage: Check the code here
A Stream is a container of data that allow applying serie of operations on the data in a lazy way. You start by creating the stream by giving the initial data:
$s = Stream::of('Hello World'); // Stream('Hello World')
$s = Stream::of('Hello World', 'Foo', 58); // Stream(['Hello World', 'Foo', 58])Once you have a Stream, you can start applying operations on it. Each call returns a new Stream (Streams are immutable) and all operation calls are pure (No side effect !). Because operations are not applying immediately but are just saved to be applied when get() is called !
use Tarsana\Functional\Stream;
use Tarsana\Functional as F;
$s = Stream::of('temp.txt') // initializing the Stream with the filename
->then('file_get_contents') // Reading the content of the file
->then(F\regReplace('/[^a-zA-Z0-9 ]/', ' ')) // removing non-alphanumeric chars
->then(F\split(' ')) // Splitting each line into words and concatenating results
->filter(F\notEq('')) // removing empty words
->reduce(function($words, $w){
if (!isset($words[$w]))
$words[$w] = 0;
$words[$w] ++;
return $words;
}, []); // transform the content to an array associating each word to occurencesTill now no operation was really applied, this means that the file is not yet read !
Now when we really need the result on the operations which can have side effects (Reading the file in this case). We call the get() method; It will run all the operations and gets the final result.
Assuming that the file temp.txt contains the following:
Once you have a Stream, you can start applying operations on it.
Each call returns a new Stream **(Streams are immutable)** and all operation calls are **pure**
(No side effect !). Because operations are not applying immediately
but are just saved to be applied when `get()` is called !
Doing
print_r($s->get());Will output
Array
(
[Once] => 1
[you] => 2
[have] => 1
[a] => 2
[Stream] => 2
[can] => 1
[start] => 1
[applying] => 2
[operations] => 2
[on] => 1
[it] => 1
[Each] => 1
[call] => 1
[returns] => 1
[new] => 1
[Streams] => 1
[are] => 4
[immutable] => 1
[and] => 1
[all] => 1
[operation] => 1
[calls] => 1
[pure] => 1
[No] => 1
[side] => 1
[effect] => 1
[Because] => 1
[not] => 1
[immediately] => 1
[but] => 1
[just] => 1
[saved] => 1
[to] => 1
[be] => 1
[applied] => 1
[when] => 1
[get] => 1
[is] => 1
[called] => 1
)
Check documentation for full list of methods available
Any feedback or contribution is welcome. Enjoy !