| Safe Haskell | Safe-Inferred |
|---|---|
| Language | Haskell2010 |
Distribution.Backpack
Description
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
Synopsis
- data OpenUnitId
- openUnitIdFreeHoles :: OpenUnitId -> Set ModuleName
- mkOpenUnitId :: UnitId -> ComponentId -> OpenModuleSubst -> OpenUnitId
- data DefUnitId
- unDefUnitId :: DefUnitId -> UnitId
- mkDefUnitId :: ComponentId -> Map ModuleName Module -> DefUnitId
- data OpenModule
- openModuleFreeHoles :: OpenModule -> Set ModuleName
- type OpenModuleSubst = Map ModuleName OpenModule
- dispOpenModuleSubst :: OpenModuleSubst -> Doc
- dispOpenModuleSubstEntry :: (ModuleName, OpenModule) -> Doc
- parsecOpenModuleSubst :: CabalParsing m => m OpenModuleSubst
- parsecOpenModuleSubstEntry :: CabalParsing m => m (ModuleName, OpenModule)
- openModuleSubstFreeHoles :: OpenModuleSubst -> Set ModuleName
- abstractUnitId :: OpenUnitId -> UnitId
- hashModuleSubst :: Map ModuleName Module -> Maybe String
OpenUnitId
data OpenUnitId Source #
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 lossily represent it as a 'DefiniteUnitId 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
Constructors
| IndefFullUnitId ComponentId OpenModuleSubst | Identifies a component which may have some unfilled holes;
specifying its |
| DefiniteUnitId DefUnitId | Identifies a fully instantiated component, which has
been compiled and abbreviated as a hash. The embedded |
Instances
openUnitIdFreeHoles :: OpenUnitId -> Set ModuleName Source #
Get the set of holes (ModuleVar) embedded in a UnitId.
mkOpenUnitId :: UnitId -> ComponentId -> OpenModuleSubst -> OpenUnitId Source #
Safe constructor from a UnitId. The only way to do this safely is if the instantiation is provided.
DefUnitId
A UnitId for a definite package. The DefUnitId invariant says
that a UnitId identified this way is definite; i.e., it has no
unfilled holes.
Instances
unDefUnitId :: DefUnitId -> UnitId Source #
mkDefUnitId :: ComponentId -> Map ModuleName Module -> DefUnitId Source #
Create a DefUnitId from a ComponentId and an instantiation
with no holes.
OpenModule
data OpenModule Source #
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.
Constructors
| OpenModule OpenUnitId ModuleName | |
| OpenModuleVar ModuleName |
Instances
openModuleFreeHoles :: OpenModule -> Set ModuleName Source #
Get the set of holes (ModuleVar) embedded in a Module.
OpenModuleSubst
type OpenModuleSubst = Map ModuleName OpenModule Source #
An explicit substitution on modules.
NB: These substitutions are NOT idempotent, for example, a valid substitution is (A -> B, B -> A).
dispOpenModuleSubst :: OpenModuleSubst -> Doc Source #
Pretty-print the entries of a module substitution, suitable
for embedding into a OpenUnitId or passing to GHC via --instantiate-with.
dispOpenModuleSubstEntry :: (ModuleName, OpenModule) -> Doc Source #
Pretty-print a single entry of a module substitution.
parsecOpenModuleSubst :: CabalParsing m => m OpenModuleSubst Source #
Inverse to dispModSubst.
Since: Cabal-syntax-2.2
parsecOpenModuleSubstEntry :: CabalParsing m => m (ModuleName, OpenModule) Source #
Inverse to dispModSubstEntry.
Since: Cabal-syntax-2.2
openModuleSubstFreeHoles :: OpenModuleSubst -> Set ModuleName Source #
Get the set of holes (ModuleVar) embedded in a OpenModuleSubst.
This is NOT the domain of the substitution.
Conversions to UnitId
abstractUnitId :: OpenUnitId -> UnitId Source #
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.
hashModuleSubst :: Map ModuleName Module -> Maybe String Source #
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.