Enhance PHP syntax now.
PHP's syntax isn't great, there are things which may be done better. What if you could easily extend it in user-space (i.e. by a function written in PHP)? Start experimenting today.
How it works
PHP uses autoloading to locate a class on disk when it it being used for the first time. PhpEnhancer registers a special autoloader, which not only locates the class on disk, but also enhances it on the fly.
That being said, PhpEhnancer can enhance only classes loaded by autoloading mechanism and cannot do anything with those files loaded via require/include in PHP. That's actually not a problem, because most projects use autoloading for 99% of the classes. (Usually, the only exception is the autoloader itself being loaded manually and then it takes all the work).
Should this be a problem, you can try adding a php extension which gets deeper into PHPs core and can hook onto anything ;)
Simple examples are in
Example of a complete project based on Nette sandbox is in branch sandbox. Just clone it, install dependencies using composer and you're ready to start your own project with enhanced php.