#10697: Change template-haskell API to allow NOUNPACK, lazy annotations -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: Template Haskell | Version: 7.10.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: #5290, #8347 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Description changed by RyanGlScott: Old description:
Currently, the {{{template-haskell}}} API is lagging behind what is possible with GHC's strictness annotations in data types, especially since the advent of {{{StrictData}}}. Currently, {{{template-haskell}}} has {{{Strict}}}:
{{{#!hs data Strict = IsStrict | NotStrict | Unpacked }}}
But it appears that there are actually nine different combinations of packedness and strictness annotations:
{{{#!hs data A = A Int -- No unpackedness, no strictness data A = A !Int -- No unpackedness, strict data A = A ~Int -- No unpackedness, lazy data A = A {-# NOUNPACK #-} A Int -- NOUNPACK, no strictness data A = A {-# NOUNPACK #-} A !Int -- NOUNPACK, strict data A = A {-# NOUNPACK #-} A ~Int -- NOUNPACK, lazy data A = A {-# UNPACK #-} A Int -- UNPACK, no strictness data A = A {-# UNPACK #-} A !Int -- UNPACK, strict data A = A {-# UNPACK #-} A ~Int -- UNPACK, lazy }}}
It seems like the most consistent thing to do would be change {{{Strict}}} and add {{{Unpack}}} to the {{{template-haskell}}} API:
{{{#!hs data Strict = IsStrict | NotStrict | IsLazy
data Unpack = Unpack | NoUnpack | NotUnpacked
type UnpackStrictType = (Unpack, Strict, Type)
type VarUnpackStrictType = (Name, Unpack, Strict, Type) }}}
And so on.
New description: Currently, the {{{template-haskell}}} API is lagging behind what is possible with GHC's strictness annotations in data types, especially since the advent of {{{StrictData}}}. Currently, {{{template-haskell}}} has {{{Strict}}}: {{{#!hs data Strict = IsStrict | NotStrict | Unpacked }}} But it appears that there are actually nine different combinations of packedness and strictness annotations: {{{#!hs data A = A Int -- No unpackedness, no strictness data A = A !Int -- No unpackedness, strict data A = A ~Int -- No unpackedness, lazy data A = A {-# NOUNPACK #-} Int -- NOUNPACK, no strictness data A = A {-# NOUNPACK #-} !Int -- NOUNPACK, strict data A = A {-# NOUNPACK #-} ~Int -- NOUNPACK, lazy data A = A {-# UNPACK #-} Int -- UNPACK, no strictness data A = A {-# UNPACK #-} !Int -- UNPACK, strict data A = A {-# UNPACK #-} ~Int -- UNPACK, lazy }}} It seems like the most consistent thing to do would be change {{{Strict}}} and add {{{Unpack}}} to the {{{template-haskell}}} API: {{{#!hs data Strict = IsStrict | IsLazy | NoStrictAnnot data Unpack = Unpack | NoUnpack | NoUnpackAnnot type UnpackStrict = (Unpack, Strict) type UnpackStrictType = (UnpackStrict, Type) type VarUnpackStrictType = (Name, UnpackStrict, Type) type StrictType = UnpackStrictType type VarStrictType = VarUnpackStrictType }}} And so on. -- -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10697#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler