pufuwozu/roy — pull request #51 by paulmillr (2011-12-04 18:02:29+00:00)
Title: Implement unicode identifiers. Related: #47.

This adds unicode identifiers support.

As in [ES5 7.6](http://es5.github.com/#x7.6), ECMAscript identifier starts with `$`, `_`, or letter from (Lu Ll Lt Lm Lo Nl) unicode groups.

Then identifier can also be from groups (Nd, Mn, Mc, or Pc).

Roy identifier cannot have letter u03BB (greek lowercase lambda) because it's used in anonymous functions.

As an example, roy's std lib now has three math constants:

```roy
let π = Math.PI
let π2 = π * 2
// tauday.com
let τ = π2
```

It's implemented using my [unicode-categories](https://github.com/paulmillr/unicode-categories) library.

CoffeeScript also has this problem, see jashkenas/coffee-script#1718.