Here is interesting point: is php5 already fully compatible with utf8 so
you can really code it using utf8? Does interpreter completely
understand utf8 ?
...snipped...
The bytecode compiler can compile source code using for example chinese
chars for variable and function names. I didn't test class constructs
but that should be also no problem. (tested in php 5.2.x)
All reserved tokens/operators/white space chars using the same single
byte value in ASCII and UTF-8.