Re: [Yaml-core] Bug in PyYaml parsing of Scientific Notation

[Steve H. <SHowell@DevIS.com>]

On Mon, 2002-12-09 at 14:13, Tim Hochberg wrote:
> 
> I just signed up to this mailing list and perhaps this should be going
> straight to Steve Howell, so chastise me if appropriate.
> 

The YAML mailing list has hardly been overwhelmed with PyYaml patches,
nor has my inbox. :)

Either one's fine by me, and I don't think anybody else objects. 

> Anyway, I've been using YAML on and off for a few months now and it seems
> like a great tool. However I recently bumped into a bug in PyYamls handling
> of numbers in scientific notation. In particular a round trip with the
> number 2e-9 results in a string.
> 
> The details: 2e9 gets written out as 2e-009 and when it gets read back this
> does not get matched by SCIENTIFIC_REGEX, which requires a dot, so it
> instead is read as a string. I suspect the fix is just to relax the regex
> to:
> 
> "^[-+]?[0-9][0-9,]*[0-9.]*[eE][-+][0-9]+$"
> 
> You could probably remove the commas from SCIENTIFIC REGEX as well as the
> commas after the point in FLOAT_REGEX as well. This would result in:
> 
> FLOAT_REGEX      = re.compile("^[-+]?[0-9][0-9,]*\.[0-9]*$")
> SCIENTIFIC_REGEX = re.compile^[-+]?[0-9]+(\.[0-9]*)?[eE][-+][0-9]+$")
> 
> FWIW, all tests continue to run fine with these on python 2.2. Disclaimer:
> I'm not a regular user of regular expressions, so the above could be
> completely bogus and I'd never know. They seem to work though.
> 
> [Alternatively, you could use "^[-+]?[0-9](,?[0-9][0-9][0-9])*\.[0-9]*$" for
> the float regex, but that's probably overkill].
> 

I applied your patch to PyYaml 0.31.

Thanks for taking the time to submit it.

Cheers,

Steve