It is possible to match only valid JavaScript identifiers with a really long
regex (like coco and CoffeeScriptRedux does), but CoffeeScript uses a much
simpler one, which allows a bit too much.
Quoting jashkenas/coffeescript#1718 #issuecomment-2152464 @jashkenas:
> But it still seems very much across the "worth it" line. You'll get the
> SyntaxError as soon as it hits JS, and performance aside -- even the increase
> in filesize for our browser coffee-script.js lib seems too much, considering
> this is something no one ever does, apart from experimentation.
In short, CoffeeScript treats any non-ASCII character as part of an identifier.
However, unicode spaces should be excluded since having blank characters as part
of a _word_ is very confusing. This commit does so, while still keeping the
regex really simple.
* Supplement missing block before `ELSE` token only for multi-line `if`.
* Don't prematurely remove `TERMINATOR` before `ELSE` (so we can differentiate single- and multi-line forms).
* Cleanup: Remove `WHEN` from `EXPRESSION_CLOSE`. (Only `LEADING_WHEN` tokens are preceded by a `TERMINATOR`.)
* Cleanup: Remove really old, inapplicable text from comment.
Simon Lydell