Magento2 plugin

plugins.php

<?php
function displayAndConvert($input) {
    display($input);
    return strtoupper($input);
}
// displayAndConvert('foo') -> display('foo') -> return 'FOO'

function beforeDisplayAndConvert($input) {
    return $input . ' - With before';
}
// displayAndConvert('foo') -> display('foo - With before') -> return 'FOO - WITH BEFORE'

function afterDisplayAndConvert($input) {
    return $input . ' - With after';
}
// si que le after: displayAndConvert('foo') -> display('foo') -> return 'FOO - With after'
// si que le before+after: displayAndConvert('foo') -> display('foo - With before') -> return 'FOO - WITH BEFORE - With after'

function aroundDisplayAndConvert($subject, $proceed, $input) {
    display('coucou');
    $result = $proceed($input . ' - With around');
    display('RES: ' . $result);
    return $input . ' - Yolo';
}
// si que around:
//  displayAndConvert('foo')
//      -> display('coucou')
//      -> display('foo - With around')
//      -> display('RES: FOO - WITH AROUND')
//      -> return 'foo - Yolo'
//
// si around, before et after (avec sort order par défaut, cf http://devdocs.magento.com/guides/v2.0/extension-dev-guide/plugins.html):
//  displayAndConvert('foo')
//      -> display('coucou')
//      -> display('foo - With before - With around')
//      -> display('RES: FOO - WITH BEFORE - WITH AROUND - WITH AFTER')
//      -> return 'foo - With before - Yolo'