Create Number parser

[sebastienros]

Fixes #106
Fixes #130

[sebastienros]

@lahma was able to delete TokenResult and use ReadOnlySpan<char> instead.
@gumbarros this should allow to remove the custom logic in ncalc

[gumbarros]

@lahma was able to delete TokenResult and use ReadOnlySpan<char> instead. @gumbarros this should allow to remove the custom logic in ncalc

Nice, will this also work in the exponent parser https://github.com/ncalc/ncalc/pull/193/files?

[lahma]

Now a small feat implementing this! Added some comments, maybe some make sense, maybe not. Would be nice to see perf numbers for before/after.

[sebastienros]

@gumbarros I made NumberLiteralBase public such that you can create custom parser type and logic that will still use Parlot internally.

@lahma I made flags even faster by pre-computing them!