Hi, Am Donnerstag, den 16.04.2020, 14:48 +0000 schrieb Simon Peyton Jones via ghc-steering-committee:
It would be really helpful to have a single source of truth. Perhaps someone (Joachim or anyone else) can write a Google doc that describes, as precisely as possible, the proposal that he is advocating. Or get the proposal authors to do so. Just saying “a variant where the value does not need to be in scope” does not count as a specification (to me).
the variant is described in 6.1.2 of the proposal: https://github.com/tweag/ghc-proposals/blob/local-do/proposals/0000-local-do... has a spec (“resolves to any (>>=) that is exported by any module aliased by the name M, independently of whether it is in scope (i.e. imported).” and an I think enlightening example (albeit with an odd duplication of imports).
Then. 1. import MyMonad as M (+) other operations do not need to be qualified (-) unqualified `>>=` may be ambiguous
What are “other operations”?
Anything else exported from MyMonad that the user might want to use.
Why might “>>=” be ambiguous? I think the answer is: because MyMonad must export it (to use in M.do), but it may already be in scope from the Prelude.
Correct.
I’m strongly inclined against inventing new complexity in the module system, unless it is absolutely unavoidable. More to specify, more to explain, more to understand, more to implement.
And you are sure that the complexity of this is more than that of “fully settled” types? Cheers, Joachim -- Joachim Breitner mail@joachim-breitner.de http://www.joachim-breitner.de/