OverloadedLists

Isaac Dupree ml at isaac.cedarswampstudios.org
Thu Feb 14 22:34:32 CET 2013


On 02/14/2013 10:10 AM, Simon Peyton-Jones wrote:
> | Finally I managed to build again (don't know what's wrong with my
> | system, I built on a virtual machine instead now), and the tests pass. I
> | attached the four patches, they were created with git diff --no-prefix,
> | and their name specifies the submodule they are to be applied to. I hope
> | it isn't to late to include them in 7.8. Should I publish them somewhere
> | else also, or is this fine?
>
> Great.  It's done!  Thanks for all your work on this.
>
> Would you like to update the wiki page? http://hackage.haskell.org/trac/ghc/wiki/OverloadedLists

Wiki says: "GHC, during the typechecking and desugaring phases, uses 
whatever is in scope with the names of fromList, toList and fromListN"

Does this mean that if OverloadedLists is on and more than one fromList 
or toList is in scope (even if one of them is GHC.Exts.fromList/toList), 
then list literals and patterns (resp.) will not compile?  I just 
selfishly don't want to hide those in every import list (and to give up 
polymorphic list literals altogether in modules that define/export a 
monomorphic fromList).  Anyhow, good work on this!

(Admission: I've been importing Data.Map etc. unqualified because I want 
the ambiguities with Prelude: I want to force my code to say List.filter 
just like it says Map.filter.  Is there a better way to do this? :)

-Isaac




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