A lexical change (a breaking change, but trivial to fix)

[Timon Gehr]

On 07/07/2012 11:39 PM, Mehrdad wrote:
> This might sound silly,

+1.

> but how about if D stopped allowing 0..2 as a
> range, and instead just said "invalid floating-point number"?
>
> Fixing it en masse would be pretty trivial... just run a regex to replace
> "\b(\d+)\.\."
> with
> "\1 .. "
> and you're good to go.
>
> (Or if you want more accuracy, just take the compiler output and feed it
> back with a fix -- that would work too.)
>
> The benefit, though, is that now you can do maximal munch without
> worrying about this edge case... which sure makes it easier to make a
> lexer.
>
> Thoughts?

It does not make it easier to create a lexer, because this is not
actually an edge case worth explicitly testing for.

switch(input.front){
     case '0'..'9': ...
     case 'a'..'f', 'A'..'F': ...
     case '.': if('0'>input[1]||input[1]>'9') break;
         ...
}