While the general case for TH is intractable, it would probably be pretty simple to write a script that can generate tags locations for identifiers generated by specific, known cases - particularly​ Persistent.
At work I took a bit of a different approach, and wrote a generator that looks at the TH output and writes out code to different modules for each model. This lets the tooling just work. Probably overkill in the context of Snowdrift, though... On Nov 14, 2017 4:55 AM, "Bryan Richter" <br...@snowdrift.coop> wrote: > Hi! > > On 11/13/2017 06:30 AM, jake wrote: > > > In Haskell code, I'd like the ability to click an identifier and go > > to its definition. How do I do this? > > You're not alone in your frustration. I think the only people who have > a really good answer to this question are users of emacs + intero (+ > stack). > > https://commercialhaskell.github.io/intero/ > > If you're willing, I'd suggest giving it a try. > > Unfortunately for me, I use vim, and I haven't plunged into emacs yet. > I'm also frustrated with a lack of good go-to-definition support. > Here's my solution so far: > > 1. Use vim. Vanilla vim has: > > - keyword search (# and *) in a single file > - keyword expansion (^p, ^n) across all loaded files > - grep integration (:grep) > - creates a quickfix list, navigable with :cnext and :cprev > - support for ctags, which *does* provide go-to-defintion for the > local project (see following) > > 2. Use fast-tags to generate ctags > > - Works on the local project, with caveats due to Template Haskell: > - Doesn't support yesod routes (generated with TH) > - Doesn't support persistent model types (generated with TH) > > 3. Use all the web search engines > > - For reasons unknown to me, different engines index different parts > of hackage. I try: > - Stackage search https://www.stackage.org/ > - Hoogle https://www.haskell.org/hoogle/ > - Hayoo http://hayoo.fh-wedel.de/ > > 4. Use codex https://hackage.haskell.org/package/codex > > - Theoretically, this indexes all of your dependencies, and provides > ctags go-to-definition for *everything*. I've tried it before, and > it was quite nice! > - I don't use it right now, but maybe that's just because I changed > operating systems and didn't load it back up yet. > > > I would like to know what your methods are, > > since mine aren't working too well. This issue > > <https://github.com/rikvdkleij/intellij-haskell/issues/237> may > > explain some of my problems, but I'd like to hear your solutions. > > > > If you're interested, here's what I've tried: > > > > > > Recently, I have installed IntelliJ and its Haskell plugin: the > > above being my primary motivation -- supposedly, this IDE/plugin > > combo has the feature. Problem: only rarely does it work. > > I don't know anybody who uses IntelliJ + the Haskell plugin. :( I am > not sure what state it is in. It might be a lost cause. > > Free/open source Haskell developers almost exclusively do not use > IDEs. Some people *defend* this state of affairs, but I think the only > real reason is that nobody has poured the intense time, money, and > effort into creating one that *works* and is well-integrated with the > compiler. > > > To give my actual case: > > > > I was perusing sdb.hs and saw: > > > > -- | Seeing as I use this everywhere toText_ :: FilePath -> Text > > toText_ = format fp > > > > And I though to myself, "Hmm. I wonder where fp is defined? And > > format?" So I use the "Go to Declaration" feature. > > Just for reference, here's how I figured out the answer to this > myself. (Off the top of my head, I had no idea what 'fp' was.) > > First, I opened the file in vim and did a keyword search with * > (http://vimhelp.appspot.com/pattern.txt.html#star). I found nothing, > so I knew it wasn't a file-local definition. I knew for a fact that I > would not export a name as meaningless as 'fp', so I didn't bother > searching elsewhere in the project. Finally, I looked at the import > list. Luckily, this file has really good imports, and there are only > two possibilities: > > import Turtle hiding (need, opt) > import Development.Shake > > Since fp is being used by 'format', which I knew was part of Turtle, > I had a strong feeling that fp was part of Turtle, too. > > Sure enough, I searched Stackage and there it was, the second hit: > > search result: > https://www.stackage.org/lts-9.13/hoogle?q=fp > > definition: > https://www.stackage.org/haddock/lts-9.13/turtle-1.3.6/ > Turtle-Format.html#v:fp > > > Hope that helps! > > > _______________________________________________ > Dev mailing list > Dev@lists.snowdrift.coop > https://lists.snowdrift.coop/mailman/listinfo/dev > >
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