Changes between Version 4 and Version 5 of MultiParamTypeClassesDilemma


Ignore:
Timestamp:
Feb 14, 2006 8:42:17 PM (10 years ago)
Author:
ravi@…
Comment:

--

Legend:

Unmodified
Added
Removed
Modified
  • MultiParamTypeClassesDilemma

    v4 v5  
    44
    55== Options for solving the dilemma ==
    6  1. Examine a limited version of functional dependencies (are there any concrete proposals?)
     6 1. Examine a limited version of functional dependencies (see below for one solution)
    77 1. Put AssociatedTypes on the fast-track for sainthood
    88 1. Punt: declare FunctionalDependencies as an extension and figure out a way to "bless" extensions
     
    1515== Tickets ==
    1616 * [ticket:90 solve the MultiParamTypeClassDilemma]
     17
     18== Proposed Solutions ==
     191.  Adopt functional dependencies with the FD-conditions from the [http://research.microsoft.com/Users/simonpj/Papers/fd-chr/ CHR paper] together with the "complex relaxation rule" described at the bottom of the FunctionalDependencies page (also see the CHR paper, sect. 6).
     20
     21Pro:
     22 * allows a safe version of FunctionalDependencies that can support the monad transformer library
     23Con:
     24 * complex specification for what is and is not allowed in classes and instance with functional dependencies
     25 * not clear whether this could be forwards-compatible with associated types