My take is that we don't have these because they would slow down compilation times and add bloat. But enough people have asked for them (and, I can think of a few times when I would use them myself) that I think they should be added.
It is conceivable that we could make the instances only when DEBUG is on. That would, I believe, involve some unsavory CPP, and may not be worth it. What do others think? Richard > On Mar 18, 2017, at 9:03 AM, Tom Sydney Kerckhove <[email protected]> > wrote: > > Dear GHC Devs, > > I am trying to use GHC as a library but I'm having a lot of trouble with > understanding what everything means. > Up to now, I have been able to figure out what to do by reading the > sources, but it ocured to me that much of my struggles could have been > mitigated if the relevant types had Show instances. > > I am specifically talking about the types concerning type checking. > TypecheckedModule and everything below that. > I am aware that most of the types have an Outputable instance, but > there are two problems with that: > > - 'Outputting' a value requires DynFlags. (yes, I know about pprTrace) > - These instances are not intended to show the internal structure of a > value, but rather a 'human readable' representation of a value. > > My questions for you: > > - Is there a reason that there are no derived 'Show' instances for most > types? > - Would you accept a diff that adds these? > > Thank you for your time. > > -- > Tom Sydney Kerckhove > _______________________________________________ > ghc-devs mailing list > [email protected] > http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs _______________________________________________ ghc-devs mailing list [email protected] http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs
