I build a (so far) pretty nice templating mechanism for a cms. Now I also added a set of developer tools to the UI for a better UX during development. The only problem I'm left with is that I have to use create_function to add my templates, and therefore have lambda_xyz instead of meaningful template or function names.
Question: Is there a way/work around to give meaningful names to lambda functions in php?
This reference might be able to point you in the right direction:
http://php.net/manual/en/functions.anonymous.php
Anonymous functions require PHP 5 >= 5.3.0
$function_name = 'meaningful_name';
// PHP 5 >= 5.3.0
$$function_name = function(){echo "I am connected to a meaningful name";};
// PHP 4 >= 4.0.1, PHP 5
$$function_name = create_function('', 'echo "I am connected to a meaningful name";');
// Then you can call your function like this
$meaningful_name();
If this isn't what you are looking for, can you update your question with what you are trying to accomplish in more detail?
Related
Update - this question applies to PHP < 8.2 - for 8.2+, You have access to Randomizer
PHP supports `mt_rand()` and `mt_srand()`, but these are global and static.
I notice in the PHP C source that mt_rand uses a engine_mt19937 instance; is there a way in PHP to instantiate our own instance of this RNG so we can control its seed?
On PHP 8.2+, yes. See #AlexHowansky's answer for that. On earlier PHP versions, no.
Your link to the source code points to the master branch, which already has the PHP 8.2 logic in it since it was officially released last month. That is why the master branch includes the reference to an MT19937 engine.
On older versions (e.g. the latest 8.1 branch) you can see that mt_rand() did not use a configurable engine but just checked if it was already seeded. PHP 8.1 and earlier used a single global generator for mt_rand() so it is not possible to have multiple RNGs with different seeds if you want to use the native functions.
Having said that, you could probably roll your own implementation of an MT19937 RNG for PHP 8.1. Others have.
is there a way in PHP to instantiate our own instance of this RNG so we can control its seed?
With PHP 8.2+, yes. See the \Random classes. You can do something like:
$rand1 = new \Random\Engine\Mt19937($seed1);
$value1 = $rand1->generate();
$rand2 = new \Random\Engine\Mt19937($seed2);
$value2 = $rand2->generate();
After complaining about the tumultuous task of writing the keyword function over and over, I asked someone about an easier way. The person said that PHP is going to have arrow function syntax similar to es6.
const foo = (x, y) => {
return x + y;
};
As I continued to look into this, I have not been able to find many examples online.
Can someone of the right caliber please expound upon this?
At this point, I am also really interested in how this would fit into the OOP aspect of PHP.
Original answer from February 2018:
This appears to be the syntax described in https://wiki.php.net/rfc/arrow_functions. It does have an experimental implementation.
In the arrow functions proposal, it is mentioned that it's an alternative to the "short closures" proposal, https://wiki.php.net/rfc/short_closures
As of February 2018, the current versions of PHP are 7.1.4 / 7.2.2.
I can't find any confirmation that either proposal has been approved. The former is in the "Under Discussion" state, the latter is "Declined / Withdrawn in favor of http://wiki.php.net/rfc/arrow_functions". I think it's too soon to know whether it will be adopted in any future version of PHP.
Update December 2019:
The feature has been released in PHP 7.4, according to https://www.php.net/manual/en/migration74.new-features.php
Arrow functions provide a shorthand syntax for defining functions with
implicit by-value scope binding.
<?php
$factor = 10;
$nums = array_map(fn($n) => $n * $factor, [1, 2, 3, 4]);
But the usage has not been updated yet in the PHP manual page about Anonymous Functions
Here's a blog going into detail: https://stitcher.io/blog/short-closures-in-php
Yes. The new RFC has been accepted for PHP 7.4 https://wiki.php.net/rfc/arrow_functions_v2
Based on RFC for PHP 7.4 code could look like
$users->map(
fn($user) => $user->first_name.' '.$user->last_name
);
instead of
$users->map(function($user) {
return $user->first_name.' '.$user->last_name;
});
I have a php script. I want to check the php version compatibility that each function of this script has.
For example the script has the hash() function. If we look at php.net site it says that this function was added (PHP 5 >= 5.1.2, PECL hash >= 1.1).
So assuming that this script has only this function we say that it is compatible with php 5.1.2 and onwards. Is there any software tool that can scan the script and tell you the changelog of every function and possibly gives you the lowest possible score e.g. (php version 4.3 and on)? It is a bit tedious to check manually every function in the script.
Thank you in advance
As PHP supports dynamic function/method names, just searching through the source code would not give reliable results.
Example:
$function = 'strpos';
$result = $function(...);
You might use xdebug function traces together with a 100% test coverage. This could give you all function names which had been called during a test suite run with 100% coverage - meaning all code has run. But even this isn't reliable as you would have to make sure, that your test suite covered all possible dynamic function names what is impossible. (assuming the max length of a function name is unlimited)
My final answer is: this isn't reliably possible.
First off, this is an exact duplicate of these four questions:
Highlight the difference between two strings in PHP
JavaScript based diff utility
How to do text DIFF using PHP?
Calculate text diffs in PHP
It seems as though times have changed since these questions were first asked and I am wondering what is a good tool now-a-days for this sort of comparison? I have looked at (additionally to those questions):
https://github.com/nuxodin/diff_match_patch-php
http://pear.php.net/package/Text_Diff
https://github.com/paulgb/simplediff/blob/5bfe1d2a8f967c7901ace50f04ac2d9308ed3169/simplediff.php
http://www.raymondhill.net/finediff/viewdiff-ex.php
But all of the ones I get are either unmantained now or seem a little dodgy in that they are not used that much (and some even hint that they are not very performant) and the PEAR one worries me. I hate to install PEAR for one little module not only that but it seems like throwing a brick through my own window to install it for such a small module in comparison to PEAR in general not only that but the module has been superseded and placed on a different channel (dunno why?). I would use the PEAR version if it is my only choice but I want to use the upto date package.
Does anyone know of a well used and currently maintained or built in function (even if it is a PHP extension) text diff for PHP and/or JavaScript (JQuery as well)?
Ok so it has been a while.
I actually decided to look around at what other people use and stumbled upon what Yii ( http://www.yiiframework.com ) uses.
They actually use the PEAR module for their text_diff and they use it in its new form on the horde channel. It seems that text_diff is now a horde project but you can just as easily integrate a version of it into your application and that is what Yii does by default (it comes pre-bundled with a version of it).
So I searched around a bit to find out how they used it and how to get into it and I came across:
public function actionDiff()
{
Yii::import('gii.components.TextDiff');
$model=$this->prepare();
if(isset($_GET['id']) && isset($model->files[$_GET['id']]))
{
$file=$model->files[$_GET['id']];
if(!in_array($file->type,array('php', 'txt','js','css')))
$diff=false;
elseif($file->operation===CCodeFile::OP_OVERWRITE)
$diff=TextDiff::compare(file_get_contents($file->path), $file->content);
else
$diff='';
$this->renderPartial('/common/diff',array(
'file'=>$file,
'diff'=>$diff,
));
}
else
throw new CHttpException(404,'Unable to find the code you requested.');
}
In CCodeGenerator for their Gii module ( http://www.yiiframework.com/doc/api/1.1/CCodeGenerator/ ). The important part is where they actually hook into the PEAR module:
$diff=TextDiff::compare(file_get_contents($file->path), $file->content);
By reading in the contents of two files which produces a diffed output.
Originally I did not want to use PEAR because of the bloat but this module is quite slim for a fully featured text_diff so I have decided to go with this. Not only that but, at the moment, it is the only text_diff module that has truly worked for me so I am keeping with the best, even if the best is quite memory hungry.
Have you tried one of Philippe's two solutions on this thread?
Quoted here:
In PHP. array_diff compares the first against the second array and
returns the difference.
$a1 = str_split('abcdefghijklmnop');
$a2 = str_split('abcdefghi');
echo join('', array_diff($a1, $a2)); // jklmnop
This will work as well:
$s1 = 'abcdefghijklmnop';
$s2 = 'abcdefghi';
echo str_replace(str_split($s2), '', $s1); // jklmnop
This could handle $s2 = 'ghiabcdef'; as well because str_replace() is fed with an
array, not a string.
I have a PHP program using MySQL that I will be making open-source, including a simple installer, and I want to make it as easy to install on any server with PHP4 or 5 and MySQL 4 as possible.
I've included an installer to make it user-friendly, but I need to know what are the things I can do to make it most likely to install on every server.
I'll start: I've made sure to use full PHP tags (not short) like this <?php ?> and to make sure all variables are declared prior to using them, like so $nVar = (isset($_POST['nVar']) ? $_POST['nVar'] : NULL);.
What other best practices should be incorporated in a PHP app for the best cross-server compatability?
Just a few hints, from the top of my head
The class { __constructor } is deprecated.
Dont use GLOBAL
Use split and join
Watch out for file magic byte recognition functions
The get_class get_parent_class alphanumerical changed to accept camelcasing - use strtolower on returned value before comparing