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Beginner Projects

ghc/haddock (Alex B.)

Revamp the haddock type-class specializer

For convenient display of type-class instances haddock inserts the instance head into the type-class methods type signatures. However in the current implementation haddock does no alpha-conversion on type variables if they are not bound by forall. See https://github.com/haskell/haddock/issues/654 for an example.

This is an easy starter ticket. Changes would be pretty local `rename` (see https://github.com/haskell/haddock/blob/master/haddock-api/src/Haddock/Interface/Specialize.hs#L229) and could be done in a few hours. If you are interested in this task talk to Alex Biehl.

Handle `pattern` exports

The PatternSynonyms extension introduced `pattern` exports which can be used to export single constructors of a data type without the data type itself. Currently when haddock sees a name in an export list it tries to find its corresponding declaration. From an ASTs viewpoint single data constructors do not have a declaration. Instead they are nested in its owning data declaration. See https://github.com/haskell/haddock/issues/653 for an example.

A fix would try to beef up `findDecl` to handle the case of a data constructor name by returning the owning data declaration (see https://github.com/haskell/haddock/blob/master/haddock-api/src/Haddock/Interface/Create.hs#L701). `mkExportDecl` then would prepare the constructor for rendering. If you are interested in this task talk to Alex Biehl.

Finish --show-interface

When debugging it is commonly needed to look into the generated haddock-interface files. https://github.com/haskell/haddock/pull/645 laid the groundwork for such a feature. It adds a command line parameter which dumps an interface file to json. If you are interested in this task talk to Alex Biehl.

Qua-Kit (Artem)


Writing Documentation for Haskell Packages (David, Franz)

Spock (Alex T.)

yarn2nix / yarn-lock

@Profpatsch (twitter), Profpatsch (#freenode)

I’m writing a parser for yarn.lock files (megaparsec); they are parsed into a multi-keyed map, decycled and then put into nix files. Git dependencies are another WIP, since a prefetch pass is needed.