It took me about five minutes to arrive at the guess that this is about the syntax in Cabal files for using backpack - is that right?
What is the intent of what got implemented, anyway? Are there example use cases? Den tors 25 feb. 2021 18:14Edward Z Yang <ezy...@mit.edu> skrev: > Today, using the 'mixins' field you can rename modules that come from > other packages by manually expressing a renaming one-by-one. In some > Backpack use cases, you may have a lot of modules that you would like to > mechanically rename into some subnamespace; today, you have manually list > each renaming one by one. > > > https://github.com/haskell/cabal/pull/7303 contains an implementation of > one possible way to extend mixin syntax to support qualified renaming; the > implementation is very simple. The syntax here is based off of Richard > Eisenberg's local modules proposal ( > https://github.com/ghc-proposals/ghc-proposals/pull/283) which supports > the qualified keyword before module exports/imports which has the same > effect (bring the module into scope under a sub-module namespace). However, > the PR isn't really meant to be an end all to the discussion: it's just to > show that it's pretty simple to implement this functionality. > > > There are two primary axes which I am looking for feedback: > > > * Expressivity. The current PoC implementation only permits > unconditionally prefix-ing all modules that would have been brought into > scope by the mixin; e.g., transforming module A to Prefix.A. Edward Kmett > has expressed that in some cases, he would like it if you could implement > the import as a suffix. One could also imagine allowing arbitrary string > transformations. Opinions on where to draw the line for expressivity are > solicited. > > > * Syntax. The current syntax is "pkgname qualified Prefix" as it is > symmetric with "pkgname hiding (A, B)" and it was simple to implement. But > I am not particularly attached to this syntax, and am open to other > suggestions. If we permit suffixing, a wildcard based syntax like "pkgname > (* as *.Suffix)" may be preferable (though modestly more complex to specify > and implement; for example, is the glob recursive over dots?). Edward Kmett > has offered some other possibilities at > https://github.com/haskell/cabal/issues/7290#issue-812744575 > > > Thanks Oleg for reminding me to send this RFC to this mailing list. > > > Cheers, > > Edward > _______________________________________________ > cabal-devel mailing list > cabal-devel@haskell.org > http://mail.haskell.org/cgi-bin/mailman/listinfo/cabal-devel >
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