Re: [Nano-devel] [PATCH] syntax: go: fix bugs in number literal regex

[Benno Schulenberg]

Op 04-01-18 om 03:22 schreef Tom Levy:
> > -color red "\<[0-9]+\.[0-9]*([Ee][+-]?[0-9]+)?i?\>"
> > -color red "\<[0-9]+[Ee][+-]?[0-9]+i?\>"
> > -color red "\<[0-9]+i\>"
> > +color red "\<[0-9]+(\.[0-9]*)?([Ee][+-]?[0-9]+)?i?\>"
>
> The new regex is not equivalent to the old.
>
> Go has an ugly inconsistency with octal literals: a leading 0 denotes
> octal only in integer literals. So 010 == 8, but 010.0 == 10.0.

Hmm.  Okay.  How about this:

  color red "\<0([0-7]*|[xX][0-9a-fA-F]+)\>"
  color red "(\<0+|\B)\.[0-9]+([Ee][+-]?[0-9]+)?i?\>"
  color red "\<[1-9][0-9]*(\.[0-9]*)?([Ee][+-]?[0-9]+)?i?\>"

> The old regex was careful not to match invalid octal integer literals
> such as "09". The new regex isn't careful.
>
> Reference: https://golang.org/ref/spec#Integer_literals

Benno