Run a variable through several functions - php

Question

I am attempting to run a variable through several functions to obtain a desired outcome.
For example, the function to slugify a text works like this:
// replace non letter or digits by -
$text = preg_replace('~[^\\pL\d]+~u', '-', $text);
// trim
$text = trim($text, '-');
// transliterate
$text = iconv('utf-8', 'us-ascii//TRANSLIT', $text);
// lowercase
$text = strtolower($text);
// remove unwanted characters
$text = preg_replace('~[^-\w]+~', '', $text);
However, we can see that there is a pattern in this example. The $text variable is passed through 5 function calls like this: preg_replace(..., $text) -> trim($text, ...) -> iconv(..., $text) -> strtolower($text) -> preg_replace(..., $text).
Is there a better way we can write the code to allow a variable sieve through several functions?
One way is to write the above code like this:
$text = preg_replace('~[^-\w]+~', '', strtolower(iconv('utf-8', 'us-ascii//TRANSLIT', trim(preg_replace('~[^\\pL\d]+~u', '-', $text), '-'))));
... but this way of writing is a joke and mockery. It hinders code readability.

Answer 1

Since your "function pipeline" is fixed then this is the best (and not coincidentally simplest) way.
If the pipeline were to be dynamically constructed then you could do something like:
// construct the pipeline
$valuePlaceholder = new stdClass;
$pipeline = array(
// each stage of the pipeline is described by an array
// where the first element is a callable and the second an array
// of arguments to pass to that callable
array('preg_replace', array('~[^\\pL\d]+~u', '-', $valuePlaceholder)),
array('trim', array($valuePlaceholder, '-')),
array('iconv', array('utf-8', 'us-ascii//TRANSLIT', $valuePlaceholder)),
// etc etc
);
// process it
$value = $text;
foreach ($pipeline as $stage) {
list($callable, $parameters) = $stage;
foreach ($parameters as &$parameter) {
if ($parameter === $valuePlaceholder) {
$parameter = $value;
}
}
$value = call_user_func_array($callable, $parameters);
}
// final result
echo $value;
See it in action.

Answer 2

use this as a combination of all five
$text = preg_replace('~[^-\w]+~', '', strtolower(iconv('utf-8', 'us-ascii//TRANSLIT', trim(preg_replace('~[^\\pL\d]+~u', '-', $text), '-'))));
but use as you are trying.because it is good practice rather than writing in one line.