| ... | ... | @@ -21,7 +21,9 @@ the memory-model semantics of IORefs. |
|
|
|
## Class system
|
|
|
|
|
|
|
|
|
|
|
|
The work on the class system has focused on resolving the [MultiParamTypeClassesDilemma](multi-param-type-classes-dilemma).
|
|
|
|
The work on the class system has focused on resolving the [MultiParamTypeClassesDilemma](multi-param-type-classes-dilemma). The core of the dilemma is that multi-parameter typeclasses are a popular extension
|
|
|
|
that are strongly desired in Haskell'. However, many important uses of MPTCs (like the monad transformer library) require additional extensions to resolve ambiguities in their typechecking. Historically, FunctionalDependecies? have been used for this purpose, but they are very tricky to implement and are also difficult to specify in a way that
|
|
|
|
guarantees the termination of typechecking. [AssociatedTypes](associated-types) are a possible replacement, but they have not yet been completely implemented in any Haskell implementation.
|
|
|
|
|
|
|
|
## Libraries
|
|
|
|
|
| ... | ... | |
