unbundle fusion

[timotheecour]

fixes nim-lang/fusion#25

nimble install fusion or --path:/pathto/fusion/src or --path:fusion:/pathto/fusion/src/fusion (nim-lang/RFCs#291) (and possibly with a fixed hash/tag nimble install fusion@#1234) is a much saner approach than copying fusion sources (at a fixed hash) to $nim/lib/fusion, which can only cause problems down the line when user also has nimble install fusion as it'd lead to duplicate fusion modules (eg: link error if there's an exportc symbol, or surprising module resolution in case of import fusion/foo)

note, this doesn't preclude using fusion from within tools/ or compiler/ (refs nim-lang/fusion#22), in fact it makes it easier to, by avoiding the above mentioned issues of potential duplicate modules.

future work

• add fusion to important_packages.nim, just like other regular nimble packages
• start adopting semver in fusion just like any other nimble package (refs RFC: adopt semver, like almost all nimble packages fusion#30)

links

The current plan is that we don't bundle Fusion anymore with Nim

#16875 (comment)

[planetis-m]

I kind of liked it... Can it be removed from nimble instead?

[timotheecour]

I kind of liked it... Can it be removed from nimble instead?

I'm confused by your +1 and this comment ;-)

I don't see the point in removing fusion from nimble; it should either be a separate nimble package (like all other packages) or it should be merged inside nim repo (ie same git history), anything else seems like a brittle hack to me. And I prefer the 1st option (separate nimble package) as an "extended batteries" option.

[planetis-m]

Either way its a problem that needs to be resolved and I support your initiative :)

[timotheecour]

ping: I had to rebase because of conflict bitrot /cc @Araq

The current plan is that we don't bundle Fusion anymore with Nim

[timotheecour]

PTAL

[Araq]

In followup PRs "finish.nim" (and also choosenim if that's still a thing) should offer to install the Fusion package.