Convert to a Python package

[khaeru]

Excepting tests and helper code for us devs, the package consists of two lines that define one object:

from iam_units import registry

How to review:

• Will merging this PR break any existing code? If not, then let's handle any adjustments in additional PRs to keep things quick and tidy.
• The name 'units' is taken on PyPI: https://pypi.org/project/units/, so I went with 'iam_units'. Good? I could also live with 'ia_units'.

[gidden]

@khaeru took a look and all seems very immaculate. @znicholls, FYI that this is now installable. @danielhuppmann I guess we can do a quick patch on pyam to depend on this?

Also, very happy to see that setup.py now looks like it's actually easy to implement instead of the complicated nonsense I've had to work with for the past 10 years!

[gidden]

Ah, I forgot to mention. We use pyam-iamc name on PyPI since pyam was taken. That could be one pattern to follow here.

[danielhuppmann]

Minor comments on the copyright holders, update-script and fixing a broken link to the new pyam-docs

[danielhuppmann]

@danielhuppmann I guess we can do a quick patch on pyam to depend on this?

Yes, @dependabot proves quite useful here. But unless this is also released via conda and/or pip, I don't think we'll get around the submodule hassle (but that's a minor hassle now that it's set up).

[danielhuppmann]

We use pyam-iamc name on PyPI since pyam was taken. That could be one pattern to follow here.

-1. Don't think that units-iamc has a nice ring to it...

[znicholls]

@znicholls, FYI that this is now installable

Thanks @gidden and thanks @danielhuppmann for your comments about authorship. Both appreciated and this looks like a very easy maintenance way of getting the behaviour you need.

For completeness, we needed a units repository in silicone which had wide gas and gwp context coverage so I've actually already split out https://github.com/openscm/openscm-units from https://github.com/openscm/scmdata. I didn't raise this here as I thought the discussions in #9 suggested a package wasn't desired. I'm happy to work out a way to combine openscm-units and this repo into a shared resource if there's desire. Also fine to keep them separate for the time being though (openscm-units certainly doesn't have the feature of being 'as low-maintenance as possible' because of its desire to include more features).

But unless this is also released via conda and/or pip, I don't think we'll get around the submodule hassle

+1 from me, you can't release a package on PyPI that has url based install dependencies. Hence if you want pyam to depend on this, you'll need to make this pip installable too or stick with the submodule stuff. If you want an automated deployment workflow for this repo, the jobs from here onwards might be helpful (you need to set the right secrets, see details here and alter hard-coded names but then you're done).

[gidden]

LGTM - vote then for iam-units as suggested by @khaeru

[khaeru]

Sorry @danielhuppmann @gidden —one additional point based on #16 (comment): since this is now no longer simply content (a text file) but code, I will change the license to GPL3. Good?

@znicholls thanks for the pointer to the GitHub workflow examples and information about the other package.

[danielhuppmann]

Sorry @danielhuppmann @gidden —one additional point based on #16 (comment): since this is now no longer simply content (a text file) but code, I will change the license to GPL3. Good?

Fine for me!

[danielhuppmann]

great work @khaeru, thanks for the effort! Approving, though I feel the list of authors should still be changed - see inline comment.