pygmt.config: Support tab auto-completion for all GMT defaults

[seisman]

Description of proposed changes

Let pygmt.config() support tab auto-completion by manually setting the __signature__ attribute of the pygmt.config() class, inspired by the implementation in #1282.

Screenshot:

Fixes #

Reminders

• Run make format and make check to make sure the code follows the style guide.
• Add tests for new features or tests that would have caught the bug that you're fixing.
• Add new public functions/methods/classes to doc/api/index.rst.
• Write detailed docstrings for all functions/methods.
• If wrapping a new module, open a 'Wrap new GMT module' issue and submit reasonably-sized PRs.
• If adding new functionality, add an example to docstrings or tutorials.

Slash Commands

You can write slash commands (/command) in the first line of a comment to perform
specific operations. Supported slash commands are:

• /format: automatically format and lint the code
• /test-gmt-dev: run full tests on the latest GMT development version

[weiji14]

The tab autocomplete is nice! Just need to decide how to list the 135 (if I didn't miscount) parameters in https://docs.generic-mapping-tools.org/6.4/gmt.conf.html 😅

[weiji14]

Hmm, would we need to manually list all the possible parameters here? I'm looking at gmt.conf.rst and https://github.com/GenericMappingTools/gmt/blob/34aa940e7a30a6dca4fc554b8dcd747dcef3e93e/src/gmt_defaults.h#L60-L211, but not sure if there's a smart way to get the whole list from the GMT C API.

[seisman]

gmt defaults can output all the keywords and their current values. So at least we can call gmt defaults and extract the keywords from the output.

[seisman]

Calling gmt defaults is not a perfect idea, because the code will be executed when importing the pygmt package. Perhaps manually maintaining the the long list of keywords is not a bad idea because the list of GMT keywords don't change much between versions.

[weiji14]

Ok I guess. Even if the list gets out of date because GMT adds new configs, people can still use it, just without tab completion.

[seisman]

The tab autocomplete is nice! Just need to decide how to list the 135 (if I didn't miscount) parameters in docs.generic-mapping-tools.org/6.4/gmt.conf.html 😅

I've manually added the long list of keywords to config.py in 2fa17a5.

The long list contains 128 normal keywords as listed by the following command:

gmt defaults | awk -F"=" '/^[^#]/ {print $1}' | sed 's/,[ \t]\?/,/g' | awk '{printf("\"%s\",\n", $1)}'

plus 8 special keywords like FONT and FONT_ANNOT, so the total number is 136.

[seisman]

I think it makes more sense to also put the self.special_params attribute out of the __init__ function.

[weiji14]

Yeah, I was thinking about that too. Maybe create a _special_params variable to hold that dictionary.

[seisman]

Done in 318501b, and the variable name is _special_keywords instead of _special_params.

[weiji14]

Nice work, just double checked one by one and it looks good!