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

[Jonathan M Davis]

On Saturday, July 07, 2012 15:01:50 H. S. Teoh wrote:
> On Sat, Jul 07, 2012 at 11:39:59PM +0200, Mehrdad wrote:
> > This might sound silly, but how about if D stopped allowing   0..2
> > as a range, and instead just said "invalid floating-point number"?
> 
> [...]
> 
> I like writing 0..2 as a range. It's especially nice in array slice
> notation, where you _want_ to have it as concise as possible.
> 
> OTOH, having implemented a D lexer before (just for practice, not
> production quality), I do see how ambiguities with floating-point
> numbers can cause a lot of code convolutions.
> 
> But I'm gonna have to say no to this one; *I* think a better solution
> would be to prohibit things like 0. or 1. in a float literal. Either
> follow it with a digit, or don't write the dot. This will also save us a
> lot of pain in the UFCS department, where 4.sqrt is currently a pain to
> lex. Once this is done, 0..2 is no longer ambiguous, and any respectable
> DFA lexer should be able to handle it with ease.

+1

I think that it's ridiculous that 1. and .1 are legal. 1.f was fixed, so I was 
shocked to find out recently that 1. and .1 weren't.

- Jonathan M Davis