2011/9/15 Greg Weber
I should be clear that in my counter point I am using Ruby, not Haskell on those projects. In Ruby one can use a string for the name of a class (which will be evaluated later) and other general dynamic typing tricks to avoid cyclical dependencies.
Ah, okay. Sure, late binding (that's what it's called) makes it convenient.
I have worked on one large Yesod project. I felt they were creating artificially shortened field names in some cases (that I found difficult to understand/remember) to try and ease the pain of large prefixed record selectors.
I can understand that. Accessors like reviewAssignSubmissionId for a ReviewAssign record are pretty tedious but at least I don't have trouble remembering them.
However, Yesod does create all the records with prefixes in one module/file- so all the types are in there. They create a new model file for each model (conceptually, but not for a model representing simple embedded data). The model file can import all the record types.
Right, that's what I do. Types in one big types file, and then the functions for the model in Project.Model.X which imports the types file. This is an internal project, but it will be released as open source in a few months so showing you the haddock output isn't a big deal: http://chrisdone.com/confy-doc/ My militantness regarding adding haddock docs is scant due to deadline pressures as you'd expect, but it's not so bad. E.g. checkout http://chrisdone.com/confy-doc/Confy-Model-Conference.html and it's blatant I'm using a lot of other types. All entities or entity-like things are in: http://chrisdone.com/confy-doc/Confy-Types-Entities.html and enums in http://chrisdone.com/confy-doc/Confy-Types-Enums.html And do not look at http://chrisdone.com/confy-doc/Confy-Model-Tables.html because it is frightening and will make you go bald. If you're already bald, feel free! HaskellDB and its HList-like record system.
Personally I would prefer to define my type in the model file so I can quickly see my type with the related code if it were possible, but it seems that it isn't.
I guess it can be possible with a lot of discipline and patience. Maybe others have done this in large projects and found it not so bad?