##JavaScript to PHP
This tool transforms JavaScript to PHP. Just for fun.
This is a proof-of-concept started at a hackathon recently and as far as I can tell, hasn't been done before. So why not? There's some interesting aspects of the two languages that make this a really interesting challenge: lexical scope, prototypal inheritance, duality of + operator in JS, PHP's implicit variable declaration, etc. A lot of this had to be implemented in runtime helpers with type checking, but it turns out it's totally doable.
There are plenty of "compile to JS" languages out there (Coffee, TypeScript, Dart), but few good choices in the PHP world**. PHP is ubiquitous in bulk hosting (80+ percent of the market). PHP runs on Google App Engine, AppFog, Rackspace Cloud Sites and every LAMP stack in the world. So if you need to host on PHP but don't like writing PHP, well you're hosed. ...unless you could write in JS and deploy to PHP!
Maybe so. But if you were to write in one language and compile to PHP, JavaScript (or a subset thereof) would be a great choice. There's plenty of tooling, libraries, community, etc. Plus web developers have to know JS anyway because it's in the browser. OK, I'm not suggesting you write production code using this, but who knows, maybe it will mature into something you can take to production in the future. I could imagine someone creating a cool thing in JS and then compiling to PHP to put it up on CodeCanyon. The same application might then be run on Node using Fibers and the JVM via Nahsorn or DynJS.
Sure, you pay a performance penalty at runtime, but seriously, have you run mainstream PHP apps before? It's not like the performance bar is too high (I think a default WP install runs 27 SQL queries to render the homepage). Your app is likely not CPU bound anyway (and if it is, then you should be running Node + worker processes or some other awesome solution).
At this point I'm focusing on correctness, not performance, and this is very alpha stuff, so don't expect too much.
The core language is mostly implemented and has some tests (Object, Array, Math lib, String methods, etc) but there is no interface to the outside world besides console.log(). There's no file-system, HTTP or Database modules and there's no formal way to call into PHP from JS at this point.
Feel free to contribute if this interests you.
git clone [email protected]:sstur/js2php.git
cd js2php
npm install
echo "var a = 1; console.log(a + 1)" > example.js
node js2php example.js > example.php
php -f example.php
We're using the awesome esprima JavaScript parser with rocambole to walk the AST and escope to figure out variable scope, hoist function declarations and so on. After AST manipulation tools/codegen.js generates the PHP code from walking the tree.
Various constructs get wrapped in helper functions, for instance, property access, method calls, &&, || and + operators. The runtime helpers for this mostly live in php/helpers and there are a bunch of classes in php/classes for Array, RegExp and such. All this PHP gets packaged into your output file, or you can save it to a standalone runtime and reference that from your output file like so:
node js2php --runtime-only > runtime.php
node js2php --runtime runtime.php example.js > example.php
You can also specify the output file using -o or --out and you can compile multiple input files into one output file like so:
node js2php -o example.php file1.js file2.js
Have a play with the online demo. The generated code will look something like this:
<?php
require_once("runtime.php");
$HelloWorld = new Func("HelloWorld", function($this_, $arguments, $greeting) {
set($this_, "greeting", $greeting);
});
set(get($HelloWorld, "prototype"), "go", new Func(function($this_, $arguments, $subject) use (&$console) {
call_method($console, "log", get($this_, "greeting"), $subject);
}));
call_method(x_new($HelloWorld, "Hi"), "go", "world");It's not particularly elegant, but it's human-readable and has all the basics we need to implement standards-compliant JS in PHP.
There are a few other "compile to PHP" languages out there, but none have the kind of support and tooling of an established language such as JavaScript. Haxe is probably the most popular, but I also came across Pharen (a Lisp implementation), Mammouth (similar to CoffeeScript) and Pratphall (TypeScript syntax).
Run npm test which is the same as node js2php --test. Requires PHP 5.3+ or HHVM.
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