mirror of
https://github.com/idris-lang/Idris2.git
synced 2024-12-30 07:02:24 +03:00
225 lines
7.5 KiB
Idris
225 lines
7.5 KiB
Idris
module Deriving.Common
|
|
|
|
import Data.SnocList
|
|
import Language.Reflection
|
|
|
|
%default total
|
|
|
|
------------------------------------------------------------------------------
|
|
-- Being free of a variable
|
|
|
|
||| IsFreeOf is parametrised by
|
|
||| @ x the name of the type variable that the functioral action will change
|
|
||| @ ty the type that does not contain any mention of x
|
|
export
|
|
data IsFreeOf : (x : Name) -> (ty : TTImp) -> Type where
|
|
||| For now we do not bother keeping precise track of the proof that a type
|
|
||| is free of x
|
|
TrustMeFO : IsFreeOf a x
|
|
|
|
||| We may need to manufacture proofs and so we provide the `assert` escape hatch.
|
|
export -- %unsafe -- uncomment as soon as 0.7.0 is released
|
|
assert_IsFreeOf : IsFreeOf x ty
|
|
assert_IsFreeOf = TrustMeFO
|
|
|
|
||| Testing function deciding whether the given term is free of a particular
|
|
||| variable.
|
|
export
|
|
isFreeOf : (x : Name) -> (ty : TTImp) -> Maybe (IsFreeOf x ty)
|
|
isFreeOf x ty
|
|
= do isOk <- flip mapMTTImp ty $ \case
|
|
t@(IVar _ v) => t <$ guard (v /= x)
|
|
t => pure t
|
|
pure TrustMeFO
|
|
|
|
------------------------------------------------------------------------------
|
|
-- Being a (data) type
|
|
|
|
public export
|
|
record IsType where
|
|
constructor MkIsType
|
|
typeConstructor : Name
|
|
parameterNames : List (Argument Name, Nat)
|
|
dataConstructors : List (Name, TTImp)
|
|
|
|
wording : NameType -> String
|
|
wording Bound = "a bound variable"
|
|
wording Func = "a function name"
|
|
wording (DataCon tag arity) = "a data constructor"
|
|
wording (TyCon tag arity) = "a type constructor"
|
|
|
|
isTypeCon : Elaboration m => Name -> m (List (Name, TTImp))
|
|
isTypeCon ty = do
|
|
[(_, MkNameInfo (TyCon _ _))] <- getInfo ty
|
|
| [] => fail "\{show ty} out of scope"
|
|
| [(_, MkNameInfo nt)] => fail "\{show ty} is \{wording nt} rather than a type constructor"
|
|
| _ => fail "\{show ty} is ambiguous"
|
|
cs <- getCons ty
|
|
for cs $ \ n => do
|
|
[(_, ty)] <- getType n
|
|
| _ => fail "\{show n} is ambiguous"
|
|
pure (n, ty)
|
|
|
|
export
|
|
isType : Elaboration m => TTImp -> m IsType
|
|
isType = go Z [] where
|
|
|
|
go : Nat -> List (Argument Name, Nat) -> TTImp -> m IsType
|
|
go idx acc (IVar _ n) = MkIsType n (map (map (minus idx . S)) acc) <$> isTypeCon n
|
|
go idx acc (IApp _ t (IVar _ nm)) = case nm of
|
|
-- Unqualified: that's a local variable
|
|
UN (Basic _) => go (S idx) ((Arg emptyFC nm, idx) :: acc) t
|
|
_ => go (S idx) acc t
|
|
go idx acc (INamedApp _ t nm (IVar _ nm')) = case nm' of
|
|
-- Unqualified: that's a local variable
|
|
UN (Basic _) => go (S idx) ((NamedArg emptyFC nm nm', idx) :: acc) t
|
|
_ => go (S idx) acc t
|
|
go idx acc (IAutoApp _ t (IVar _ nm)) = case nm of
|
|
-- Unqualified: that's a local variable
|
|
UN (Basic _) => go (S idx) ((AutoArg emptyFC nm, idx) :: acc) t
|
|
_ => go (S idx) acc t
|
|
go idx acc t = fail "Expected a type constructor, got: \{show t}"
|
|
|
|
------------------------------------------------------------------------------
|
|
-- Being a (data) constructor with a parameter
|
|
-- TODO: generalise?
|
|
|
|
public export
|
|
record ConstructorView where
|
|
constructor MkConstructorView
|
|
params : SnocList (Name, Nat)
|
|
conArgTypes : List (Count, Argument TTImp)
|
|
|
|
export
|
|
constructorView : TTImp -> Maybe ConstructorView
|
|
constructorView (IPi fc rig pinfo x a b) = do
|
|
let Just arg = fromPiInfo fc pinfo x a
|
|
| Nothing => constructorView b -- this better be a boring argument...
|
|
let True = rig /= M1
|
|
| False => constructorView b -- this better be another boring argument...
|
|
{ conArgTypes $= ((rig, arg) ::) } <$> constructorView b
|
|
constructorView f = do
|
|
MkAppView _ ts _ <- appView f
|
|
let range = [<] <>< [0..minus (length ts) 1]
|
|
let ps = flip mapMaybe (zip ts range) $ \ t => the (Maybe (Name, Nat)) $ case t of
|
|
(Arg _ (IVar _ nm), n) => Just (nm, n)
|
|
_ => Nothing
|
|
pure (MkConstructorView ps [])
|
|
|
|
------------------------------------------------------------------------------
|
|
-- Satisfying an interface
|
|
--
|
|
-- In order to derive Functor for `data Tree a = Node (List (Tree a))`, we need
|
|
-- to make sure that `Functor List` already exists. This is done using the following
|
|
-- convenience functions.
|
|
|
|
export
|
|
withParams : FC -> (Nat -> Maybe TTImp) -> List (Argument Name, Nat) -> TTImp -> TTImp
|
|
withParams fc params nms t = go nms where
|
|
|
|
addConstraint : Maybe TTImp -> Name -> TTImp -> TTImp
|
|
addConstraint Nothing _ = id
|
|
addConstraint (Just cst) nm =
|
|
let ty = IApp fc cst (IVar fc nm) in
|
|
IPi fc MW AutoImplicit Nothing ty
|
|
|
|
go : List (Argument Name, Nat) -> TTImp
|
|
go [] = t
|
|
go ((arg, pos) :: nms)
|
|
= let nm = unArg arg in
|
|
IPi fc M0 ImplicitArg (Just nm) (Implicit fc True)
|
|
$ addConstraint (params pos) nm
|
|
$ go nms
|
|
|
|
||| Type of proofs that something has a given type
|
|
export
|
|
data HasType : (nm : Name) -> (ty : TTImp) -> Type where
|
|
TrustMeHT : HasType nm ty
|
|
|
|
export
|
|
hasType : Elaboration m => (nm : Name) ->
|
|
m (Maybe (ty : TTImp ** HasType nm ty))
|
|
hasType nm = catch $ do
|
|
[(_, ty)] <- getType nm
|
|
| _ => fail "Ambiguous name"
|
|
pure (ty ** TrustMeHT)
|
|
|
|
||| Type of proofs that a type is inhabited
|
|
export
|
|
data IsProvable : (ty : TTImp) -> Type where
|
|
TrustMeIP : IsProvable ty
|
|
|
|
export
|
|
isProvable : Elaboration m => (ty : TTImp) ->
|
|
m (Maybe (IsProvable ty))
|
|
isProvable ty = catch $ do
|
|
ty <- check {expected = Type} ty
|
|
ignore $ check {expected = ty} `(%search)
|
|
pure TrustMeIP
|
|
|
|
||| Type of proofs that a type satisfies a constraint.
|
|
||| Internally it's vacuous. We don't export the constructor so
|
|
||| that users cannot manufacture buggy proofs.
|
|
export
|
|
data HasImplementation : (intf : a -> Type) -> TTImp -> Type where
|
|
TrustMeHI : HasImplementation intf t
|
|
|
|
||| We may need to manufacture proofs and so we provide the `assert` escape hatch.
|
|
export -- %unsafe -- uncomment as soon as 0.7.0 is released
|
|
assert_hasImplementation : HasImplementation intf t
|
|
assert_hasImplementation = TrustMeHI
|
|
|
|
||| Given
|
|
||| @ intf an interface (e.g. `Functor`, or `Bifunctor`)
|
|
||| @ t a term corresponding to a (possibly partially applied) type constructor
|
|
||| check whether Idris2 can find a proof that t satisfies the interface.
|
|
export
|
|
hasImplementation : Elaboration m => (intf : a -> Type) -> (t : TTImp) ->
|
|
m (Maybe (HasImplementation intf t))
|
|
hasImplementation c t = catch $ do
|
|
prf <- isType t
|
|
intf <- quote c
|
|
ty <- check {expected = Type} $ withParams emptyFC (const Nothing) prf.parameterNames `(~(intf) ~(t))
|
|
ignore $ check {expected = ty} `(%search)
|
|
pure TrustMeHI
|
|
|
|
------------------------------------------------------------------------------
|
|
-- Utils
|
|
|
|
||| Optionally eta-expand if there is no argument available
|
|
export
|
|
optionallyEta : FC -> Maybe TTImp -> (TTImp -> TTImp) -> TTImp
|
|
optionallyEta fc (Just t) f = f t
|
|
optionallyEta fc Nothing f =
|
|
let tnm = UN $ Basic "t" in
|
|
ILam fc MW ExplicitArg (Just tnm) (Implicit fc False) $
|
|
f (IVar fc tnm)
|
|
|
|
||| We often apply multiple arguments, this makes things simpler
|
|
export
|
|
apply : FC -> TTImp -> List TTImp -> TTImp
|
|
apply fc t ts = apply t (map (Arg fc) ts)
|
|
|
|
||| Use unqualified names (useful for more compact printing)
|
|
export
|
|
cleanup : TTImp -> TTImp
|
|
cleanup = \case
|
|
IVar fc n => IVar fc (dropNS n)
|
|
t => t
|
|
|
|
||| Create fresh names
|
|
export
|
|
freshName : List Name -> String -> String
|
|
freshName ns a = assert_total $ go (basicNames ns) Nothing where
|
|
|
|
basicNames : List Name -> List String
|
|
basicNames = mapMaybe $ \ nm => case dropNS nm of
|
|
UN (Basic str) => Just str
|
|
_ => Nothing
|
|
|
|
covering
|
|
go : List String -> Maybe Nat -> String
|
|
go ns mi =
|
|
let nm = a ++ maybe "" show mi in
|
|
ifThenElse (nm `elem` ns) (go ns (Just $ maybe 0 S mi)) nm
|