SrcLoc/SrcSpan/Located naming

[Simon Peyton-Jones]

Yes, but a lot of the API remains somewhat accidental... so I don't want to tie us in to full backward compat.  

Whenever possible, let's retain a deprecated old type or function; but if it's difficult or inconvenient, let's not.


Concerning SrcLoc etc, we did indeed start with SrcLoc, and then moved to SrcSpan later.  I would be fine with expunging all SrcLocs in favour of SrcSpans.

Simon

| -----Original Message-----
| From: cvs-ghc-bounces at haskell.org [mailto:cvs-ghc-bounces at haskell.org] On
| Behalf Of Simon Marlow
| Sent: 21 July 2009 09:05
| To: Isaac Dupree
| Cc: cvs-ghc at haskell.org
| Subject: Re: SrcLoc/SrcSpan/Located naming
| 
| We're at the stage where the GHC API is beginning to settle down a bit,
| so it might be a good idea to keep backwards compatibility where
| possible.  If we rename things, we can leave the old names in, but
| DEPRECATED, for one release.
| 
| Cheers,
| 	Simon
| 
| On 20/07/2009 19:51, Isaac Dupree wrote:
| > Do we make any attempt to keep the GHC API consistent between major
| > releases, or is the policy generally just to make any naming changes
| > that we find fitting for GHC's purposes?
| >
| > -Isaac
| >
| >
| > Thomas Schilling wrote:
| >> I think the inconsistencies are mostly because SrcSpan was added
| >> later. Patches to improve the problematic cases would (most likely)
| >> be welcome.
| >>
| >> 2009/7/20 Isaac Dupree <ml at isaac.cedarswampstudios.org>:
| >>> is a confusing mess!
| >>> The most important module is named SrcLoc, which is acceptable.
| >>> It contains three types,
| >>> SrcLoc,
| >>> SrcSpan, which approximately is two SrcLocs (begin and end),
| >>> and Located, which combines a SrcSpan (not a SrcLoc!) with an arbitrary
| >>> other type.
| >>>
| >>> In practice (well, in my case at least) you almost always want a
| >>> SrcSpan and
| >>> not a SrcLoc.
| >>> Many of the functions on SrcLoc have "srcLoc" in their names, which
| >>> is good.
| >>>
| >>> However, so do many of the functions on Located-and-SrcSpan, which is
| >>> terrible. It gets a little worse when you combine with the (fairly
| >>> sensibly
| >>> named functions) at Name.NamedThing
| >>> noLoc, getLoc, addCLoc, combineLocs work on Locateds.
| >>> noSrcLoc, getSrcLoc, work on SrcLocs. Instead, noSrcSpan and
| >>> getSrcSpan are
| >>> the ones you want.
| >>>
| >>> Okay it's not quite as bad as I thought. You want to avoid a function
| >>> iff
| >>> it contains the whole phrase "srcLoc". But I still got confused a lot of
| >>> times. I wonder if we could rename something so that SrcLoc and Located
| >>> don't have the same word-part in them, because they aren't really
| >>> closely
| >>> enough related? Even if it's just renaming "SrcLoc" to "SrcSpot" or
| >>> something.
| >>>
| >>> It's also annoying that Name.getSrcSpan doesn't work on Locateds
| >>> (inevitable
| >>> I guess since it's type-different from NamedThing), but the function you
| >>> have to use instead is called getLoc, even though it also produces a
| >>> SrcSpan
| >>> (only the argument-type is different). Hmm.
| >>>
| >>> -Isaac
| >>>
| >>> _______________________________________________
| >>> Cvs-ghc mailing list
| >>> Cvs-ghc at haskell.org
| >>> http://www.haskell.org/mailman/listinfo/cvs-ghc
| >>>
| >>
| >>
| >>
| >
| > _______________________________________________
| > Cvs-ghc mailing list
| > Cvs-ghc at haskell.org
| > http://www.haskell.org/mailman/listinfo/cvs-ghc
| 
| _______________________________________________
| Cvs-ghc mailing list
| Cvs-ghc at haskell.org
| http://www.haskell.org/mailman/listinfo/cvs-ghc