Unicode strings for axis names

[James-Crean]

When using a unicode string such as u'latitude' instead of 'latitude', CDMS throws the following error when calling axisMatches in Axis.py :
CDMSError("Specification not acceptable: <type 'unicode'>, latitude",)

This looks like it may be a regression, as i see 76a2436 mentions that unicode strings worked at one point.

Related issue with some extra details: CDAT/vcs-js#34

[dnadeau4]

@James-Crean this is the conversion to py3. I guess basestring does not accept unicode. Can you try changing it to str in axis .py. If it work, please submit a PR.

[dnadeau4]

@James-Crean are you in py2 or py3? In py2 this works

isinstance(u"", basestring)
True

You can try this as well

isinstance("", (u"".__class__, "".__class__))

[James-Crean]

I am using python 2. isinstance(u"", basestring) returns true, but the source uses:

if isinstance(specification, str):

The conda install for vCDAT lists the following versions:

cdms2                     2.12.2018.02.06.18.32.917cab50063372d0fc67430610309c7c2ef9a695.npy1.13          py27_0    uvcdat/label/nightly
libcdms                   3.0.alpha                     0    conda-forge

I can make it use basestring and PR it if you want. (You said this is the conversion to python3 so let me know if there is a different repo or something for python2)

[dnadeau4]

@James-Crean make sure it works in python 3 as well. I am not sure that basestring is available in python3

[doutriaux1]

@dnadeau4 you're right there's no basestring in py3 the way to make it work for both 2 and 3:

try:
    basestring
except Exception:
    basestring = str

if isinstance(obj, basestring):
     print("It works")

[dnadeau4]

@doutriaux1 you will have to do that in every files which make the code cumbersome.

Why do we pass u'latitude' anyways?

I think this is cleaner.

isinstance("", (u"".__class__, "".__class__))

[dnadeau4]

This might work too.

from __future__ import unicode_literals

[doutriaux1]

because it comes from the web/json files, it's in vcdat. They can work around it of course but it is more and more likely that cdms2 will get objects coming from web/json so we need to get it to work in cdms

[doutriaux1]

@dnadeau4 yes that might work as well. It's worth a shot as it's a bit cleaner.

[dnadeau4]

In python 3, I found

from past.builtins import basestring