Escape literal whitespace within Heregex (not a dup!)

[summivox]

I've read #1668 and #2668.
Can we have \ followed by whitespace within heregex as literal whitespace (\x20)?

Example:

re =
  ///
  <link\ href=\"
  ([^"]*)
  \">
  ///

should compile to:

re = /<link\ href=\"([^"]*)\">/

current impl:

re = /<link\href=\"([^"]*)\">/

[jashkenas]

Sounds like a fine idea to me. But I think you mean you want it to compile to:

re = /<link href=\"([^"]*)\">/

... right?

[summivox]

I think they're equivalent, although I did remember / / sometimes not working (maybe I got it wrong).

[michaelficarra]

I believe you're thinking of #607.

[summivox]

Yes exactly.
So it makes sense for me to have backslash-escaped whitespace both in normal regex and heregex.

[lydell]

I am very much +1 to this, since I can't think of any case where you'd want to put ignored whitespace between a backslash and the character it is supposed to escape. I'd bet this change would cause zero real backwards-incompatibility.

[michaelficarra]

Agreed. This is fixed in CoffeeScriptRedux.

[summivox]

I was just about to pull request.
Okay then.

[jashkenas]

Considering that JS doesn't have negative lookbehind ... anyone have a bright idea about how best to tweak HEREGEX_OMIT to fix this?

[lydell]

What about HEREGEX_OMIT = /((?:\\ )?)\s+(?:#.*)?/g and foo.replace(HEREGEX_OMIT, '$1')? However, it doesn't cover a backslash at the end of the line the way CSR does it.