Proposal: `shadowenv assimilate`

Shadowenv could have a feature to convert other environment manipulation tools' configs to a format it can understand. For example:

# .env
A=b

$ shadowenv assimilate
assimilated .env as .shadowenv.d/050-dotenv.lisp

; 050-dotenv.lisp
(env/set "A" "b")

This is obviously the most trivial case, but we could do similar things for:

• .envrc
• .ruby-version
• and so on.

Because of Shadowenv's lack of ability to do much of anything dynamic at load-time, this would essentially function as a "compiler" for these environment files.

One trick to try to make these files at least marginally portable would be to replace the user's home directory in any outputs with (concat (env/get "HOME") ...).

If we wanted to keep tabs on a mapping between the original and the assimilated version, we could encode a checksum/hash of the source file in the assimilated file as a comment on the first line. With this, shadowenv or dev could potentially observe these files when entering a directory and inform the user about out-of-date-ness.

Start with the shadowenv assimilate entry point and review the example .env input and .shadowenv.d/050-dotenv.lisp output. Consider the proposed .envrc and .ruby-version cases, including the checksum and HOME portability ideas. Done should include an agreed conversion scope and working assimilation behavior for the selected formats.