One other point, while still maintaining +0 on the proposal itself:
This proposal is likely to break lots and lots of code a la the FTP, and we all remember the unpleasant surprise that the community had with that one.
If libraries@ agrees this is a worthwhile change, I think we need to let the community vote on it and its deprecation cycle.
Tom
El Jun 27, 2015, a las 3:36, Herbert Valerio Riedel
On 2015-06-26 at 18:22:16 +0200, Henning Thielemann wrote: [...]
type FilePath = String
into an abstract/opaque data type instead.
Has someone else tried the pathtype package? http://hackage.haskell.org/package/pathtype
Hm, your last point "Decisions assumed by this Proposal" seems to mean, that you want to leave out more specialised types from this proposal. That is, dir/file distinction might be defined on top of the new FilePath type.
Yes, because the proposal is meant to only make the smallest incremental change needed (i.e. change FilePath datatype, provide conversion functions) to to achieve the primary goals (reduce space/time overhead & make it a distinct type from String) in a way suitable for a future Haskell Report, while trying to stay close enough that you can still write code that works with both the H2010 and a AFPP definition of `FilePath`
Trying to redesign the FilePath type to also include dir/file distinction seemed too daunting, as there's quite some additional design-space area to explore (do drive-letters deserve a separate type? do we use DataKinds? What invariants can/shall be represented at the type-level? what errors are caught at the type-level, which are caught at runtime? etc...), parts of which may require type-system extensions, while just having a KISS-style opaque FilePath evades this.
_______________________________________________ Libraries mailing list Libraries@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries