You can see a full list of contributor guidelines in the repository. The short (And possibly out of date) version is here:
- The code has to work from PHP 5.1.2 up to nightly, as well as the latest HHVM and HHVM nightly
- Don’t write bad code
- Don’t break BC
- If you make changes make sure you run the formatter and rebuild
- Default plugins should only handle PHP functionality
- Don’t display incorrect information
- Arrays may contain references. Objects are always references. Don’t alter user input in the parser.
Setting up a dev environment
For developing on core Kint you’ll need three things:
- Composer (PHP)
- Npm (NodeJS)
- Bundler (Ruby)
If you don’t have composer do yourself a favor and learn it. If you don’t have npm or bundler that’s understandable.
In any case, Kint uses composer, npm, and bundler for development tools. Composer calls npm and bundler under the assumption that they’re in your
If all of these are installed simply run
composer install and all your dependencies will be installed automatically.
Format and Build
The reason you need composer, npm, and bundler is because they’ll let us write sloppy code and have the computer fix it for us!
Specifically, composer runs php-cs-fixer to reformat PHP code to a consistent style, while npm and bundler do the same for the JS and CSS files.
Since code style is a good thing you should always run
composer format before a commit to fix any poor code style. If you don’t CI will complain.
Since we deliver the compiled JS/CSS files in our repo you should always run
composer build before a commit to rebuild the JS/CSS files. If you don’t CI will complain.
A word on JS
In JS we’re using eslint to format our code, but unlike
php-cs-fixer it doesn’t always fix the code for you. Sometimes it will just complain loudly. If that happens you’ll have to read the errors and fix them by hand.
Kint architecture and design
Kint’s architecture can roughly be split into:
- The Kint helper that glues them together
Kint_Parser class is instantiated and loaded up with
Kint_Parser_Plugin objects and let loose on the incoming data. It returns a
Kint_Object containing information about the input data’s type, name, visibility, access path, and a list of
Kint_Object_Representations of the data. (Among other things)
When it’s done parsing it loads up all the applicable
Kint_Parser_Plugin and lets them alter the
Kint_Object at will. By the time the object gets back it will likely have even more representations of data. Each of the representations may in turn hold more
In addition to altering the
Kint_Object, the plugins may add to the
hints arrays on both the
Kint_Object and the
Kint_Object_Representation to inform the renderer as to their options.
Kint_Object can be extended to alter behavior at the object level. Again this is mostly of use in the rendering stage.
After you have a
Kint_Object representing the variable, you need to render it. What the renderer does is somewhat irrelevant. It could print out text or it could print out HTML. It could store the dumped data in a database or email it to the ISS.
If you’re using the parser on it’s own you can do whatever you want with the data, but if you want to make a renderer that’s easily integrated into Kint you’ll want to extend the
Implementing it is fairly simple: It has three methods that return strings to output.
Additionally, it has an optional
parserPlugins(array) method that lets the renderer alter the list of parser plugins before parsing. This lets renderers that can’t support plugins anyway disable them for performance.
The renderer typically uses text hints stored in the
$representation->hints arrays by the parser and its plugins to inform its rendering behavior. For example, the
blacklist hint causes the rich renderer to draw a crossed out button instead of a
The Kint helper
Kint class is a helper for dumping data. As you’ve read above, the process for a standard Kint dump goes like this:
- Create a renderer with state information (Calling file/line number, modifiers, parameter names, etc)
- Call the renderer’s
preRendermethod and echo the output
- Create a parser
- Add all the plugins you want to use to the parser
- For each variable you want to dump
- Pass it into the parser
- Pass the parser’s output
Kint_Objectto the renderer and echo the output
- Call the renderers
postRendermethod and echo the output
This is a big list, and really painful to do on your own. The
Kint class handles all of this for you. Most general options live in the
Kint class, and the
Kint class has only static properties and methods.
Kint class also uses
Kint_SourceParser to gather information about the calling code such as parameter names and modifiers.