# 1 2 3 4

[Karl Berry]

Patrice,

I wonder if we could tighten the regexp for #line this way:

- if there is only one integer (# 1), the filename is optional.
  This is, I guess, what m4 does sometimes, although I haven't tried to
  figure it out in detail, just read the documentation.
  
- but with multiple integers, the filename has to be there (# 1 "foo" 2 3).
  This is what cpp does.  As far as I can see, cpp never omits the filename.

Wdyt?

Thanks,
k