Makes "float" parser of GenTokenParser parse negative numbers.

[mstream]

Resolves #115

Makes the float parser consider a sign, if present, in front of a floating number.

[jamesdbrock]

Hi @mstream thanks for the PR! This looks like good work, and I intend to merge it unless I find some surprising problem.

I see that you have already found most of the other issues and commentary around this. I suggest that you use the
number parser instead? number is better because it round-trips with show :: Number -> String (in a JavaScript environment).

The thing about this float parser is that the whole Token module and everything in it is mostly unmaintained, and will probably be factored out into a separate package some day as soon as someone feels like doing that work.
#142 (comment)

[jamesdbrock]

the whole Token module and everything in it is mostly unmaintained, and will probably be factored out into a separate package some day as soon as someone feels like doing that work.

Actually we didn't have an issue for that yet so I just made one. #226