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| # trivial gitignore file | ||
| .cabal-sandbox/ | ||
| cabal.sandbox.config | ||
| cabal.project.local | ||
| cabal-dev/ | ||
| .hpc/ | ||
| *.hi | ||
|
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| {-# LANGUAGE FlexibleInstances #-} | ||
| {-# LANGUAGE RankNTypes #-} | ||
| {-# LANGUAGE PatternGuards #-} | ||
| {-# LANGUAGE DeriveGeneric #-} | ||
| {-# LANGUAGE DeriveDataTypeable #-} | ||
| {-# LANGUAGE GeneralizedNewtypeDeriving #-} | ||
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| -- | This module defines the core data types for Backpack. For more | ||
| -- details, see: | ||
| -- | ||
| -- <https://github.com/ezyang/ghc-proposals/blob/backpack/proposals/0000-backpack.rst> | ||
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| module Distribution.Backpack ( | ||
| -- * OpenUnitId | ||
| OpenUnitId(..), | ||
| openUnitIdComponentId, | ||
| openUnitIdFreeHoles, | ||
| mkOpenUnitId, | ||
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| -- * DefUnitId | ||
| DefUnitId, | ||
| unDefUnitId, | ||
| mkDefUnitId, | ||
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| -- * OpenModule | ||
| OpenModule(..), | ||
| openModuleFreeHoles, | ||
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| -- * OpenModuleSubst | ||
| OpenModuleSubst, | ||
| dispOpenModuleSubst, | ||
| dispOpenModuleSubstEntry, | ||
| parseOpenModuleSubst, | ||
| parseOpenModuleSubstEntry, | ||
| openModuleSubstFreeHoles, | ||
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| -- * Conversions to 'UnitId' | ||
| abstractUnitId, | ||
| hashModuleSubst, | ||
| ) where | ||
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| import Prelude () | ||
| import Distribution.Compat.Prelude hiding (mod) | ||
| import Distribution.Compat.ReadP | ||
| import qualified Distribution.Compat.ReadP as Parse | ||
| import qualified Text.PrettyPrint as Disp | ||
| import Text.PrettyPrint (hcat) | ||
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| import Distribution.ModuleName | ||
| import Distribution.Package | ||
| import Distribution.Text | ||
| import Distribution.Utils.Base62 | ||
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| import qualified Data.Map as Map | ||
| import Data.Set (Set) | ||
| import qualified Data.Set as Set | ||
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| ----------------------------------------------------------------------- | ||
| -- OpenUnitId | ||
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| -- | An 'OpenUnitId' describes a (possibly partially) instantiated | ||
| -- Backpack component, with a description of how the holes are filled | ||
| -- in. Unlike 'OpenUnitId', the 'ModuleSubst' is kept in a structured | ||
| -- form that allows for substitution (which fills in holes.) This form | ||
| -- of unit cannot be installed. It must first be converted to a | ||
| -- 'UnitId'. | ||
| -- | ||
| -- In the absence of Backpack, there are no holes to fill, so any such | ||
| -- component always has an empty module substitution; thus we can lossly | ||
| -- represent it as an 'OpenUnitId uid'. | ||
| -- | ||
| -- For a source component using Backpack, however, there is more | ||
| -- structure as components may be parametrized over some signatures, and | ||
| -- these \"holes\" may be partially or wholly filled. | ||
| -- | ||
| -- OpenUnitId plays an important role when we are mix-in linking, | ||
| -- and is recorded to the installed packaged database for indefinite | ||
| -- packages; however, for compiled packages that are fully instantiated, | ||
| -- we instantiate 'OpenUnitId' into 'UnitId'. | ||
| -- | ||
| -- For more details see the Backpack spec | ||
| -- <https://github.com/ezyang/ghc-proposals/blob/backpack/proposals/0000-backpack.rst> | ||
| -- | ||
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| data OpenUnitId | ||
| -- | Identifies a component which may have some unfilled holes; | ||
| -- specifying its 'ComponentId' and its 'OpenModuleSubst'. | ||
| -- TODO: Invariant that 'OpenModuleSubst' is non-empty? | ||
| -- See also the Text instance. | ||
| = IndefFullUnitId ComponentId OpenModuleSubst | ||
| -- | Identifies a fully instantiated component, which has | ||
| -- been compiled and abbreviated as a hash. The embedded 'UnitId' | ||
| -- MUST NOT be for an indefinite component; an 'OpenUnitId' | ||
| -- is guaranteed not to have any holes. | ||
| | DefiniteUnitId DefUnitId | ||
| deriving (Generic, Read, Show, Eq, Ord, Typeable, Data) | ||
| -- TODO: cache holes? | ||
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| instance Binary OpenUnitId | ||
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| instance NFData OpenUnitId where | ||
| rnf (IndefFullUnitId cid subst) = rnf cid `seq` rnf subst | ||
| rnf (DefiniteUnitId uid) = rnf uid | ||
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| instance Text OpenUnitId where | ||
| disp (IndefFullUnitId cid insts) | ||
| -- TODO: arguably a smart constructor to enforce invariant would be | ||
| -- better | ||
| | Map.null insts = disp cid | ||
| | otherwise = disp cid <<>> Disp.brackets (dispOpenModuleSubst insts) | ||
| disp (DefiniteUnitId uid) = disp uid | ||
| parse = parseOpenUnitId <++ fmap DefiniteUnitId parse | ||
| where | ||
| parseOpenUnitId = do | ||
| cid <- parse | ||
| insts <- Parse.between (Parse.char '[') (Parse.char ']') | ||
| parseOpenModuleSubst | ||
| return (IndefFullUnitId cid insts) | ||
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| -- | Get the 'ComponentId' of an 'OpenUnitId'. | ||
| openUnitIdComponentId :: OpenUnitId -> ComponentId | ||
| openUnitIdComponentId (IndefFullUnitId cid _) = cid | ||
| openUnitIdComponentId (DefiniteUnitId def_uid) = unitIdComponentId (unDefUnitId def_uid) | ||
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| -- | Get the set of holes ('ModuleVar') embedded in a 'UnitId'. | ||
| openUnitIdFreeHoles :: OpenUnitId -> Set ModuleName | ||
| openUnitIdFreeHoles (IndefFullUnitId _ insts) = openModuleSubstFreeHoles insts | ||
| openUnitIdFreeHoles _ = Set.empty | ||
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| -- | Safe constructor from a UnitId. The only way to do this safely | ||
| -- is if the instantiation is provided. | ||
| mkOpenUnitId :: UnitId -> OpenModuleSubst -> OpenUnitId | ||
| mkOpenUnitId uid insts = | ||
| if Set.null (openModuleSubstFreeHoles insts) | ||
| then DefiniteUnitId (unsafeMkDefUnitId uid) -- invariant holds! | ||
| else IndefFullUnitId (unitIdComponentId uid) insts | ||
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| ----------------------------------------------------------------------- | ||
| -- DefUnitId | ||
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| -- | Create a 'DefUnitId' from a 'ComponentId' and an instantiation | ||
| -- with no holes. | ||
| mkDefUnitId :: ComponentId -> Map ModuleName Module -> DefUnitId | ||
| mkDefUnitId cid insts = | ||
| unsafeMkDefUnitId (UnitId cid (hashModuleSubst insts)) -- impose invariant! | ||
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| ----------------------------------------------------------------------- | ||
| -- OpenModule | ||
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| -- | Unlike a 'Module', an 'OpenModule' is either an ordinary | ||
| -- module from some unit, OR an 'OpenModuleVar', representing a | ||
| -- hole that needs to be filled in. Substitutions are over | ||
| -- module variables. | ||
| data OpenModule | ||
| = OpenModule OpenUnitId ModuleName | ||
| | OpenModuleVar ModuleName | ||
| deriving (Generic, Read, Show, Eq, Ord, Typeable, Data) | ||
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| instance Binary OpenModule | ||
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| instance NFData OpenModule where | ||
| rnf (OpenModule uid mod_name) = rnf uid `seq` rnf mod_name | ||
| rnf (OpenModuleVar mod_name) = rnf mod_name | ||
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| instance Text OpenModule where | ||
| disp (OpenModule uid mod_name) = | ||
| hcat [disp uid, Disp.text ":", disp mod_name] | ||
| disp (OpenModuleVar mod_name) = | ||
| hcat [Disp.char '<', disp mod_name, Disp.char '>'] | ||
| parse = parseModuleVar <++ parseOpenModule | ||
| where | ||
| parseOpenModule = do | ||
| uid <- parse | ||
| _ <- Parse.char ':' | ||
| mod_name <- parse | ||
| return (OpenModule uid mod_name) | ||
| parseModuleVar = do | ||
| _ <- Parse.char '<' | ||
| mod_name <- parse | ||
| _ <- Parse.char '>' | ||
| return (OpenModuleVar mod_name) | ||
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| -- | Get the set of holes ('ModuleVar') embedded in a 'Module'. | ||
| openModuleFreeHoles :: OpenModule -> Set ModuleName | ||
| openModuleFreeHoles (OpenModuleVar mod_name) = Set.singleton mod_name | ||
| openModuleFreeHoles (OpenModule uid _n) = openUnitIdFreeHoles uid | ||
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| ----------------------------------------------------------------------- | ||
| -- OpenModuleSubst | ||
|
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| -- | An explicit substitution on modules. | ||
| -- | ||
| -- NB: These substitutions are NOT idempotent, for example, a | ||
| -- valid substitution is (A -> B, B -> A). | ||
| type OpenModuleSubst = Map ModuleName OpenModule | ||
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| -- | Pretty-print the entries of a module substitution, suitable | ||
| -- for embedding into a 'OpenUnitId' or passing to GHC via @--instantiate-with@. | ||
| dispOpenModuleSubst :: OpenModuleSubst -> Disp.Doc | ||
| dispOpenModuleSubst subst | ||
| = Disp.hcat | ||
| . Disp.punctuate Disp.comma | ||
| $ map dispOpenModuleSubstEntry (Map.toAscList subst) | ||
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| -- | Pretty-print a single entry of a module substitution. | ||
| dispOpenModuleSubstEntry :: (ModuleName, OpenModule) -> Disp.Doc | ||
| dispOpenModuleSubstEntry (k, v) = disp k <<>> Disp.char '=' <<>> disp v | ||
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| -- | Inverse to 'dispModSubst'. | ||
| parseOpenModuleSubst :: ReadP r OpenModuleSubst | ||
| parseOpenModuleSubst = fmap Map.fromList | ||
| . flip Parse.sepBy (Parse.char ',') | ||
| $ parseOpenModuleSubstEntry | ||
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| -- | Inverse to 'dispModSubstEntry'. | ||
| parseOpenModuleSubstEntry :: ReadP r (ModuleName, OpenModule) | ||
| parseOpenModuleSubstEntry = | ||
| do k <- parse | ||
| _ <- Parse.char '=' | ||
| v <- parse | ||
| return (k, v) | ||
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| -- | Get the set of holes ('ModuleVar') embedded in a 'OpenModuleSubst'. | ||
| -- This is NOT the domain of the substitution. | ||
| openModuleSubstFreeHoles :: OpenModuleSubst -> Set ModuleName | ||
| openModuleSubstFreeHoles insts = Set.unions (map openModuleFreeHoles (Map.elems insts)) | ||
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| ----------------------------------------------------------------------- | ||
| -- Conversions to UnitId | ||
|
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| -- | When typechecking, we don't demand that a freshly instantiated | ||
| -- 'IndefFullUnitId' be compiled; instead, we just depend on the | ||
| -- installed indefinite unit installed at the 'ComponentId'. | ||
| abstractUnitId :: OpenUnitId -> UnitId | ||
| abstractUnitId (DefiniteUnitId def_uid) = unDefUnitId def_uid | ||
| abstractUnitId (IndefFullUnitId cid _) = newSimpleUnitId cid | ||
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| -- | Take a module substitution and hash it into a string suitable for | ||
| -- 'UnitId'. Note that since this takes 'Module', not 'OpenModule', | ||
| -- you are responsible for recursively converting 'OpenModule' | ||
| -- into 'Module'. See also "Distribution.Backpack.ReadyComponent". | ||
| hashModuleSubst :: Map ModuleName Module -> Maybe String | ||
| hashModuleSubst subst | ||
| | Map.null subst = Nothing | ||
| | otherwise = | ||
| Just . hashToBase62 $ | ||
| concat [ display mod_name ++ "=" ++ display m ++ "\n" | ||
| | (mod_name, m) <- Map.toList subst] |
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