Repository : ssh://darcs.haskell.org//srv/darcs/ghc On branch : master
http://hackage.haskell.org/trac/ghc/changeset/5a8ac0f823c151c062a3f1903574030423bb255c >--------------------------------------------------------------- commit 5a8ac0f823c151c062a3f1903574030423bb255c Author: Simon Peyton Jones <[email protected]> Date: Wed Jun 13 17:21:09 2012 +0100 Simplify the implementation of Implicit Parameters This patch re-implements implicit parameters via a class with a functional dependency: class IP (n::Symbol) a | n -> a where ip :: a This definition is in the library module GHC.IP. Notice how it use a type-literal, so we can have constraints like IP "x" Int Now all the functional dependency machinery works right to make implicit parameters behave as they should. Much special-case processing for implicit parameters can be removed entirely. One particularly nice thing is not having a dedicated "original-name cache" for implicit parameters (the nsNames field of NameCache). But many other cases disappear: * BasicTypes.IPName * IPTyCon constructor in Tycon.TyCon * CIPCan constructor in TcRnTypes.Ct * IPPred constructor in Types.PredTree Implicit parameters remain special in a few ways: * Special syntax. Eg the constraint (IP "x" Int) is parsed and printed as (?x::Int). And we still have local bindings for implicit parameters, and occurrences thereof. * A implicit-parameter binding (let ?x = True in e) amounts to a local instance declaration, which we have not had before. It just generates an implication contraint (easy), but when going under it we must purge any existing bindings for ?x in the inert set. See Note [Shadowing of Implicit Parameters] in TcSimplify * TcMType.sizePred classifies implicit parameter constraints as size-0, as before the change There are accompanying patches to libraries 'base' and 'haddock' All the work was done by Iavor Diatchki compiler/basicTypes/BasicTypes.lhs | 28 --------- compiler/basicTypes/Unique.lhs | 3 - compiler/coreSyn/MkCore.lhs | 23 +------- compiler/deSugar/DsExpr.lhs | 6 +- compiler/ghc.cabal.in | 1 - compiler/hsSyn/HsBinds.lhs | 13 +++- compiler/hsSyn/HsExpr.lhs | 2 +- compiler/hsSyn/HsTypes.lhs | 21 ++++++- compiler/iface/BinIface.hs | 20 +------ compiler/iface/IfaceEnv.lhs | 24 +------- compiler/iface/IfaceType.lhs | 19 +------ compiler/iface/TcIface.lhs | 2 - compiler/main/DynFlags.hs | 5 ++ compiler/main/HscTypes.lhs | 10 +--- compiler/parser/Parser.y.pp | 6 +- compiler/prelude/PrelNames.lhs | 15 +++++- compiler/prelude/TysWiredIn.lhs | 41 +------------- compiler/rename/RnBinds.lhs | 7 +- compiler/rename/RnExpr.lhs | 3 +- compiler/rename/RnTypes.lhs | 11 +--- compiler/typecheck/Inst.lhs | 2 - compiler/typecheck/TcBinds.lhs | 27 +++++++-- compiler/typecheck/TcCanonical.lhs | 46 --------------- compiler/typecheck/TcErrors.lhs | 6 +- compiler/typecheck/TcExpr.lhs | 27 ++++++--- compiler/typecheck/TcHsSyn.lhs | 11 ++-- compiler/typecheck/TcHsType.lhs | 6 ++- compiler/typecheck/TcInteract.lhs | 112 ++++++++++++++++++++---------------- compiler/typecheck/TcMType.lhs | 42 ++++--------- compiler/typecheck/TcRnTypes.lhs | 23 +------ compiler/typecheck/TcSMonad.lhs | 25 ++------ compiler/typecheck/TcSimplify.lhs | 65 ++++++++++++++++++++- compiler/typecheck/TcSplice.lhs | 8 ++- compiler/typecheck/TcType.lhs | 5 +- compiler/types/IParam.lhs | 41 ------------- compiler/types/IParam.lhs-boot | 10 --- compiler/types/TyCon.lhs | 15 +----- compiler/types/Type.lhs | 42 +++++--------- compiler/types/TypeRep.lhs | 12 ++-- 39 files changed, 307 insertions(+), 478 deletions(-) Diff suppressed because of size. To see it, use: git show 5a8ac0f823c151c062a3f1903574030423bb255c _______________________________________________ Cvs-ghc mailing list [email protected] http://www.haskell.org/mailman/listinfo/cvs-ghc
