Plugin meta spec

Streamtuner2 now uses a proper plugin description scheme. Note that this is completely unrelated to the streamtuner2 or channels API, or how plugins are actually initialized (pkgutil, imp, implib, pluginbase/plugnplay).

Basically the top-level comment block is scanned on initialization. It simply lists a few key: values for documentation and technical descriptors. It's basically a subset of YAML embedded in a script comment.

# api: streamtuner2
# type: feature
# title: My Plugin
# description: Lists all the things
# version: 1.0
# category: music
# config: { name: myconf, value: 1, type: boolean, description: enable foo }
#
# And here goes a longer doc/comment.

The key names are case-insensitive of course. A few fields like title:, description: are required. Theoretically also the api: and type:. But they're only used for decorative purposes like the category: or version: field.

More interestingly the config: field can be used to describe plugin options. Default values will automatically end up in streamtuners conf.* dict, and are presented to users in the config dialog.

• A value: represents the default.
• The type: select can be used for dropdown boxes, with a select: key=VAl|key2=VAL2.. attribute for options.
• Other type: values are interpreted as strings, except type: boolean which becomes a checkbox.
• A per-option category: attribute is ignored at the moment.
• Params can be optionally quoted as in `value: "Desc, desc, desc." if they contain commas (which otherwise separate option attrs.)

And of course, the config: field can list multiple options. Simply make it multi-line (every plugin meta field can be) by indenting wrapped lines.

Why?

This scheme is designed to be language-agnostic. It originated in PHP way back (see libconfig), precisely to avoid common misdesigns.

• Meta data does not belong in code.
  Because that incurs importing them, even when they may go uninitialized/unused.
• And it certainly should not reside in externalized ini/json data stores.
  Because that's how you get ants!

The meta description block also can double as packaging format. The pack: descriptor is used by fpm/xpm -s src. Which avoids manually concocting separated setup.py/.cfg as the current Python packaging eco system does. (This is stuff which can be automated, without requiring meta information to be doubled in-code and dutifully dished up for pip/setuptools).