On Wed, Nov 17, 2010 at 9:21 PM, Thomas Schilling <nomin...@googlemail.com>wrote:
> On 17 November 2010 19:21, JP Moresmau <jpmores...@gmail.com> wrote: > > Hello, I'm the maintainer for EclipseFP, which involves using the scion > > library and the GHC API to provide IDE functionality. I have a little > issue > > that no doubt stems from me not understanding the GHC API well, and I > would > > be grateful for any light on the matter. > > I'm trying to give the user the possibility to jump to the definition of > a > > symbol in the source file. You click on the name of a function and you're > > send to the module where it's defined. So I have an AST, and somewhere > down > > the line I have an Id object representing that function call. Then I just > > use ppr alwaysQualify id to get the fully qualified name of the function, > > and I can then use the module name to retrieve the source file etc. This > > works well in cases, but not in others. It will sound silly to the gurus > on > > the list, but it's when the function has generics that it doesn't work. > So a > > function with a type class in its type signature will never be printed > > qualified. It kinda like makes sense because I suppose some work has been > > done so that it represents the function with proper types, etc., but how > can > > I get back to the original Id? How can I get back from that unqualified > Id > > to the qualified Id representing the function in the original module? > I've > > been looking round Name and OccName and all that but I'm not sure really > > what I'm looking for. > > Hope I'm making sense!! > > Thanks! > > Note that typeclass methods all live in a top-level namespace. > Qualified names are used to disambiguate between multiple names which > this is not necessary for method names. > > I presume when you want to jump to the definition of a method, you > want to do something special anyway. You probably want to jump to the > implementation of the method for the type at which it is used. If it > is used polymorphically you cannot do this (there is no statically > known definition), so you could just display its type or a list of all > known implementations. > > To find out the type at which a polymorphic or overloaded identifier > is used, you have to interpret type applications (HsWrap) and > abstractions (AbsBind). > > The GHC API provides access to all imported instances, but they > probably won't have source code annotations. Such a database must be > created separately. > > HTH > > / Thomas > > -- > Push the envelope. Watch it bend. > Thanks very much, but I'm not sure it that's the situation here. I don't mean methods on typeclasses but function defined as operating on typeclasses. For example: I have this function: overlaps :: SrcSpan -> SrcSpan -> Bool which when pretty printed gives me a qualified name And this one: findHsThing :: Search id a => (SrcSpan -> Bool) -> a -> SearchResults id Which doesn't. So findHsThing work on any Search id a, but there is only one implementation of that in one source file. So there should be a link between what's in the AST that may be using more specific type and the implementation. Thanks, -- JP Moresmau http://jpmoresmau.blogspot.com/
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