Files
newt/orig/Lib/Elab.idr
Steve Dunham 3c2615ecc1 move idris version to orig and newt version to src.
Development is being done on the newt version now.
2025-02-15 16:36:29 -08:00

1399 lines
56 KiB
Idris

module Lib.Elab
import Lib.Parser.Impl
import Lib.Prettier
import Data.List
import Data.Vect
import Data.String
import Data.IORef
import Lib.Types
import Lib.Util
import Lib.Eval
import Lib.TopContext
import Lib.Syntax
||| collectDecl collects multiple Def for one function into one
export
collectDecl : List Decl -> List Decl
collectDecl [] = []
collectDecl ((Def fc nm cl) :: rest@(Def _ nm' cl' :: xs)) =
if nm == nm' then collectDecl (Def fc nm (cl ++ cl') :: xs)
else (Def fc nm cl :: collectDecl rest)
collectDecl (x :: xs) = x :: collectDecl xs
-- renaming
-- dom gamma ren
data Pden = PR Nat Nat (List Nat)
showCtx : Context -> M String
showCtx ctx =
unlines . reverse <$> go (names ctx) 0 (reverse $ zip ctx.env (toList ctx.types)) []
where
isVar : Nat -> Val -> Bool
isVar k (VVar _ k' [<]) = k == k'
isVar _ _ = False
go : List String -> Nat -> List (Val, String, Val) -> List String -> M (List String)
go _ _ [] acc = pure acc
go names k ((v, n, ty) :: xs) acc = if isVar k v
-- TODO - use Doc and add <+/> as appropriate to printing
then go names (S k) xs (" \{n} : \{pprint names !(quote ctx.lvl ty)}":: acc)
else go names (S k) xs (" \{n} = \{pprint names !(quote ctx.lvl v)} : \{pprint names !(quote ctx.lvl ty)}":: acc)
dumpCtx : Context -> M String
dumpCtx ctx = do
let names = (toList $ map fst ctx.types)
-- I want to know which ones are defines. I should skip the `=` bit if they match, I'll need indices in here too.
env <- for (zip ctx.env (toList ctx.types)) $ \(v, n, ty) => pure " \{n} : \{pprint names !(quote ctx.lvl ty)} = \{pprint names !(quote ctx.lvl v)}"
let msg = unlines (toList $ reverse env) -- ++ " -----------\n" ++ " goal \{pprint names ty'}"
pure msg
pprint : Context -> Val -> M Doc
pprint ctx v = pure $ pprint (names ctx) !(quote (length ctx.env) v)
||| return Bnd and type for name
export
lookupName : Context -> String -> Maybe (Tm, Val)
lookupName ctx name = go 0 ctx.types
where
go : Nat -> Vect n (String, Val) -> Maybe (Tm, Val)
go ix [] = Nothing
-- FIXME - we should stuff a Binder of some sort into "types"
go ix ((nm, ty) :: xs) = if nm == name then Just (Bnd emptyFC ix, ty) else go (S ix) xs
export
lookupDef : Context -> String -> Maybe Val
lookupDef ctx name = go 0 ctx.types ctx.env
where
go : Nat -> Vect n (String, Val) -> List Val -> Maybe Val
go ix ((nm, ty) :: xs) (v :: vs) = if nm == name then Just v else go (S ix) xs vs
go ix _ _ = Nothing
-- IORef for metas needs IO
export
forceMeta : Val -> M Val
forceMeta (VMeta fc ix sp) = case !(lookupMeta ix) of
(Unsolved pos k xs _ _ _) => pure (VMeta fc ix sp)
(Solved _ k t) => vappSpine t sp >>= forceMeta
forceMeta x = pure x
public export
record UnifyResult where
constructor MkResult
-- wild guess here - lhs is a VVar
constraints : List (Nat, Val)
Semigroup UnifyResult where
(MkResult cs) <+> (MkResult cs') = MkResult (cs ++ cs')
Monoid UnifyResult where
neutral = MkResult []
data UnifyMode = Normal | Pattern
export
check : Context -> Raw -> Val -> M Tm
export
unifyCatch : FC -> Context -> Val -> Val -> M ()
-- Check that the arguments are not explicit and the type constructor in codomain matches
-- Later we will build a table of codomain type, and maybe make the user tag the candidates
-- like Idris does with %hint
isCandidate : Val -> Tm -> Bool
isCandidate ty (Pi fc nm Explicit rig t u) = False
isCandidate ty (Pi fc nm icit rig t u) = isCandidate ty u
isCandidate (VRef _ nm _ _) (Ref fc nm' def) = nm == nm'
isCandidate ty (App fc t u) = isCandidate ty t
isCandidate _ _ = False
-- This is a crude first pass
export
findMatches : Context -> Val -> List TopEntry -> M (List String)
findMatches ctx ty [] = pure []
findMatches ctx ty ((MkEntry _ name type def) :: xs) = do
let True = isCandidate ty type | False => findMatches ctx ty xs
top <- get
-- let ctx = mkCtx (getFC ty)
-- FIXME we're restoring state, but the INFO logs have already been emitted
-- Also redo this whole thing to run during elab, recheck constraints, etc.
mc <- readIORef top.metaCtx
catchError(do
-- TODO sort out the FC here
let fc = getFC ty
debug "TRY \{name} : \{pprint [] type} for \{show ty}"
-- This check is solving metas, so we save mc below in case we want this solution
-- tm <- check (mkCtx fc) (RVar fc name) ty
-- FIXME RVar should optionally have qualified names
let (QN ns nm) = name
let (cod, tele) = splitTele type
modifyIORef top.metaCtx { mcmode := CheckFirst }
tm <- check ctx (RVar fc nm) ty
debug "Found \{pprint [] tm} for \{show ty}"
writeIORef top.metaCtx mc
(nm ::) <$> findMatches ctx ty xs)
(\ err => do
debug "No match \{show ty} \{pprint [] type} \{showError "" err}"
writeIORef top.metaCtx mc
findMatches ctx ty xs)
export
contextMatches : Context -> Val -> M (List (Tm, Val))
contextMatches ctx ty = go (zip ctx.env (toList ctx.types))
where
go : List (Val, String, Val) -> M (List (Tm, Val))
go [] = pure []
go ((tm, nm, vty) :: xs) = do
type <- quote ctx.lvl vty
let True = isCandidate ty type | False => go xs
top <- get
mc <- readIORef top.metaCtx
catchError(do
debug "TRY context \{nm} : \{pprint (names ctx) type} for \{show ty}"
unifyCatch (getFC ty) ctx ty vty
mc' <- readIORef top.metaCtx
writeIORef top.metaCtx mc
tm <- quote ctx.lvl tm
((tm, vty) ::) <$> go xs)
(\ err => do
debug "No match \{show ty} \{pprint (names ctx) type} \{showError "" err}"
writeIORef top.metaCtx mc
go xs)
export
getArity : Tm -> Nat
getArity (Pi x str icit rig t u) = S (getArity u)
-- Ref or App (of type constructor) are valid
getArity _ = Z
-- Can metas live in context for now?
-- We'll have to be able to add them, which might put gamma in a ref
-- Makes the arg for `solve` when we solve an auto
makeSpine : Nat -> Vect k BD -> SnocList Val
makeSpine k [] = [<]
makeSpine (S k) (Defined :: xs) = makeSpine k xs
makeSpine (S k) (Bound :: xs) = makeSpine k xs :< VVar emptyFC k [<]
makeSpine 0 xs = ?fixme
export
solve : Env -> (k : Nat) -> SnocList Val -> Val -> M ()
export
trySolveAuto : MetaEntry -> M Bool
trySolveAuto (Unsolved fc k ctx ty AutoSolve _) = do
debug "TRYAUTO solving \{show k} : \{show ty}"
-- fill in solved metas in type
x <- quote ctx.lvl ty
ty <- eval ctx.env CBN x
debug "AUTO ---> \{show ty}"
-- we want the context here too.
top <- get
[] <- contextMatches ctx ty
| [(tm, vty)] => do
unifyCatch (getFC ty) ctx ty vty
val <- eval ctx.env CBN tm
debug "SOLUTION \{pprint [] tm} evaled to \{show val}"
let sp = makeSpine ctx.lvl ctx.bds
solve ctx.env k sp val
pure True
| res => do
debug "FAILED to solve \{show ty}, matches: \{commaSep $ map (pprint [] . fst) res}"
pure False
[nm] <- findMatches ctx ty $ toList top.defs
| res => do
debug "FAILED to solve \{show ty}, matches: \{show res}"
pure False
tm <- check ctx (RVar fc nm) ty
val <- eval ctx.env CBN tm
debug "SOLUTION \{pprint [] tm} evaled to \{show val}"
let sp = makeSpine ctx.lvl ctx.bds
solve ctx.env k sp val
pure True
trySolveAuto _ = pure False
-- export
-- solveAutos : Nat -> List MetaEntry -> M ()
-- solveAutos mstart [] = pure ()
-- solveAutos mstart (entry :: es) = do
-- res <- trySolveAuto entry
-- -- idris is inlining this and blowing stack?
-- if res
-- then do
-- top <- get
-- mc <- readIORef top.metaCtx
-- let mlen = length mc.metas `minus` mstart
-- solveAutos mstart (take mlen mc.metas)
-- else
-- solveAutos mstart es
-- Called from ProcessDecl, this was popping the stack, the tail call optimization doesn't
-- handle the traversal of the entire meta list. I've turned the restart into a trampoline
-- and filtered it down to unsolved autos.
export
solveAutos : Nat -> M ()
solveAutos mstart = do
top <- get
mc <- readIORef top.metaCtx
let mlen = length mc.metas `minus` mstart
res <- run $ filter isAuto (take mlen mc.metas)
if res then solveAutos mstart else pure ()
where
isAuto : MetaEntry -> Bool
isAuto (Unsolved fc k ctx x AutoSolve xs) = True
isAuto _ = False
run : List MetaEntry -> M Bool
run Nil = pure False
run (e :: es) =
if !(trySolveAuto e) then pure True else run es
-- We need to switch to SortedMap here
export
updateMeta : Nat -> (MetaEntry -> M MetaEntry) -> M ()
updateMeta ix f = do
top <- get
mc <- readIORef top.metaCtx
metas <- go mc.metas
writeIORef top.metaCtx $ {metas := metas} mc
where
go : List MetaEntry -> M (List MetaEntry)
go [] = error' "Meta \{show ix} not found"
go (x@((Unsolved y k z w v ys)) :: xs) = if k == ix then (::xs) <$> f x else (x ::) <$> go xs
go (x@((Solved _ k y)) :: xs) = if k == ix then (::xs) <$> f x else (x ::) <$> go xs
checkAutos : Nat -> List MetaEntry -> M ()
checkAutos ix Nil = pure ()
checkAutos ix (entry@(Unsolved fc k ctx ty AutoSolve _) :: rest) = do
ty' <- quote ctx.lvl ty
when (usesMeta ty') $ ignore $ trySolveAuto entry
checkAutos ix rest
where
usesMeta : Tm -> Bool
usesMeta (App _ (Meta _ k) u) = if k == ix then True else usesMeta u
usesMeta (App _ _ u) = usesMeta u
usesMeta _ = False
checkAutos ix (_ :: rest) = checkAutos ix rest
export
addConstraint : Env -> Nat -> SnocList Val -> Val -> M ()
addConstraint env ix sp tm = do
top <- get
mc <- readIORef top.metaCtx
let (CheckAll) = mc.mcmode | _ => pure ()
updateMeta ix $ \case
(Unsolved pos k a b c cons) => do
debug "Add constraint m\{show ix} \{show sp} =?= \{show tm}"
pure (Unsolved pos k a b c (MkMc (getFC tm) env sp tm :: cons))
(Solved _ k tm) => error' "Meta \{show k} already solved [addConstraint]"
mc <- readIORef top.metaCtx
checkAutos ix mc.metas
-- this loops too
-- solveAutos 0 mc.metas
pure ()
-- return renaming, the position is the new VVar
invert : Nat -> SnocList Val -> M (List Nat)
invert lvl sp = go sp []
where
go : SnocList Val -> List Nat -> M (List Nat)
go [<] acc = pure $ reverse acc
go (xs :< VVar fc k [<]) acc = do
if elem k acc
then do
debug "\{show k} \{show acc}"
-- when does this happen?
error fc "non-linear pattern: \{show sp}"
else go xs (k :: acc)
go (xs :< v) _ = error emptyFC "non-variable in pattern \{show v}"
-- REVIEW why am I converting to Tm?
-- we have to "lift" the renaming when we go under a lambda
-- I think that essentially means our domain ix are one bigger, since we're looking at lvl
-- in the codomain, so maybe we can just keep that value
rename : Nat -> List Nat -> Nat -> Val -> M Tm
renameSpine : Nat -> List Nat -> Nat -> Tm -> SnocList Val -> M Tm
renameSpine meta ren lvl tm [<] = pure tm
renameSpine meta ren lvl tm (xs :< x) = do
xtm <- rename meta ren lvl x
pure $ App emptyFC !(renameSpine meta ren lvl tm xs) xtm
rename meta ren lvl (VVar fc k sp) = case findIndex (== k) ren of
Nothing => error fc "scope/skolem thinger VVar \{show k} ren \{show ren}"
Just x => renameSpine meta ren lvl (Bnd fc $ cast x) sp
rename meta ren lvl (VRef fc nm def sp) = renameSpine meta ren lvl (Ref fc nm def) sp
rename meta ren lvl (VMeta fc ix sp) = do
-- So sometimes we have an unsolved meta in here which reference vars out of scope.
debug "rename Meta \{show ix} spine \{show sp}"
if ix == meta
-- REVIEW is this the right fc?
then error fc "meta occurs check"
else case !(lookupMeta ix) of
Solved fc _ val => do
debug "rename: \{show ix} is solved"
rename meta ren lvl !(vappSpine val sp)
_ => do
debug "rename: \{show ix} is unsolved"
catchError (renameSpine meta ren lvl (Meta fc ix) sp) (\err => throwError $ Postpone fc ix (errorMsg err))
rename meta ren lvl (VLam fc n icit rig t) = pure (Lam fc n icit rig !(rename meta (lvl :: ren) (S lvl) !(t $$ VVar fc lvl [<])))
rename meta ren lvl (VPi fc n icit rig ty tm) = pure (Pi fc n icit rig !(rename meta ren lvl ty) !(rename meta (lvl :: ren) (S lvl) !(tm $$ VVar emptyFC lvl [<])))
rename meta ren lvl (VU fc) = pure (UU fc)
rename meta ren lvl (VErased fc) = pure (Erased fc)
-- for now, we don't do solutions with case in them.
rename meta ren lvl (VCase fc sc alts) = error fc "Case in solution"
rename meta ren lvl (VLit fc lit) = pure (Lit fc lit)
rename meta ren lvl (VLet fc name val body) =
pure $ Let fc name !(rename meta ren lvl val) !(rename meta (lvl :: ren) (S lvl) body)
-- these probably shouldn't show up in solutions...
rename meta ren lvl (VLetRec fc name ty val body) =
pure $ LetRec fc name !(rename meta ren lvl ty) !(rename meta (lvl :: ren) (S lvl) val) !(rename meta (lvl :: ren) (S lvl) body)
lams : Nat -> List String -> Tm -> Tm
lams 0 _ tm = tm
-- REVIEW do we want a better FC, icity?, rig?
lams (S k) [] tm = Lam emptyFC "arg_\{show k}" Explicit Many (lams k [] tm)
lams (S k) (x :: xs) tm = Lam emptyFC x Explicit Many (lams k xs tm)
export
unify : Env -> UnifyMode -> Val -> Val -> M UnifyResult
(.boundNames) : Context -> List String
ctx.boundNames = map snd $ filter (\x => fst x == Bound) $ toList $ zip ctx.bds (map fst ctx.types)
maybeCheck : M () -> M ()
maybeCheck action = do
top <- get
mc <- readIORef top.metaCtx
case mc.mcmode of
CheckAll => action
CheckFirst => do
modifyIORef top.metaCtx $ { mcmode := NoCheck }
action
modifyIORef top.metaCtx $ { mcmode := CheckFirst }
NoCheck => pure ()
solve env m sp t = do
meta@(Unsolved metaFC ix ctx_ ty kind cons) <- lookupMeta m
| _ => error (getFC t) "Meta \{show m} already solved! [solve]"
debug "SOLVE \{show m} \{show kind} lvl \{show $ length env} sp \{show sp} is \{show t}"
let size = length $ filter (\x => x == Bound) $ toList ctx_.bds
debug "\{show m} size is \{show size} sps \{show $ length sp}"
let True = length sp == size
| _ => do
let l = length env
debug "meta \{show m} (\{show ix}) applied to \{show $ length sp} args instead of \{show size}"
debug "CONSTRAINT m\{show ix} \{show sp} =?= \{show t}"
addConstraint env m sp t
let l = length env
debug "meta \{show meta}"
ren <- invert l sp
-- force unlet
hack <- quote l t
t <- eval env CBN hack
catchError (do
tm <- rename m ren l t
let tm = lams (length sp) (reverse ctx_.boundNames) tm
top <- get
soln <- eval [] CBN tm
updateMeta m $ \case
(Unsolved pos k _ _ _ cons) => pure $ Solved pos k soln
(Solved _ k x) => error' "Meta \{show ix} already solved! [solve2]"
maybeCheck $ for_ cons $ \case
MkMc fc env sp rhs => do
val <- vappSpine soln sp
debug "discharge l=\{show $ length env} \{(show val)} =?= \{(show rhs)}"
unify env Normal val rhs
mc <- readIORef top.metaCtx
-- stack ...
-- checkAutos ix mc.metas
pure MkUnit
)
(\case
Postpone fc ix msg => do
-- let someone else solve this and then check again.
debug "CONSTRAINT2 m\{show ix} \{show sp} =?= \{show t}"
addConstraint env m sp t
err => do
-- I get legit errors after stuffing in solution
-- report for now, tests aren't hitting this branch
throwError err
debug "CONSTRAINT3 m\{show ix} \{show sp} =?= \{show t}"
debug "because \{showError "" err}"
addConstraint env m sp t)
unifySpine : Env -> UnifyMode -> Bool -> SnocList Val -> SnocList Val -> M UnifyResult
unifySpine env mode False _ _ = error emptyFC "unify failed at head" -- unreachable now
unifySpine env mode True [<] [<] = pure (MkResult [])
unifySpine env mode True (xs :< x) (ys :< y) = [| unify env mode x y <+> (unifySpine env mode True xs ys) |]
unifySpine env mode True _ _ = error emptyFC "meta spine length mismatch"
unify env mode t u = do
debug "Unify lvl \{show $ length env}"
debug " \{show t}"
debug " =?= \{show u}"
t' <- forceMeta t >>= unlet env
u' <- forceMeta u >>= unlet env
debug "forced \{show t'}"
debug " =?= \{show u'}"
debug "env \{show env}"
-- debug "types \{show $ ctx.types}"
let l = length env
-- On the LHS, variable matching is yields constraints/substitutions
-- We want this to happen before VRefs are expanded, and mixing mode
-- into the case tree explodes it further.
case mode of
Pattern => unifyPattern t' u'
Normal => unifyMeta t' u'
-- The case tree is still big here. It's hard for idris to sort
-- What we really want is what I wrote - handle meta, handle lam, handle var, etc
where
-- The case tree here was huge, so I split it into stages
-- newt will have similar issues because it doesn't emit a default case
unifyRest : Val -> Val -> M UnifyResult
unifyRest (VPi fc _ _ _ a b) (VPi fc' _ _ _ a' b') = do
let fresh = VVar fc (length env) [<]
[| unify env mode a a' <+> unify (fresh :: env) mode !(b $$ fresh) !(b' $$ fresh) |]
unifyRest (VU _) (VU _) = pure neutral
-- REVIEW I'd like to quote this back, but we have l that aren't in the environment.
unifyRest t' u' = error (getFC t') "unify failed \{show t'} =?= \{show u'} \n env is \{show env}"
unifyRef : Val -> Val -> M UnifyResult
unifyRef t'@(VRef fc k def sp) u'@(VRef fc' k' def' sp') =
-- unifySpine is a problem for cmp (S x) (S y) =?= cmp x y
do
-- catchError(unifySpine env mode (k == k') sp sp') $ \ err => do
Nothing <- tryEval env t'
| Just v => do
debug "tryEval \{show t'} to \{show v}"
unify env mode v u'
Nothing <- tryEval env u'
| Just v => unify env mode t' v
if k == k'
then unifySpine env mode (k == k') sp sp'
else error fc "vref mismatch \{show t'} \{show u'}"
-- Lennart.newt cursed type references itself
-- We _could_ look up the ref, eval against [] and vappSpine...
unifyRef t u@(VRef fc' k' def sp') = do
debug "expand \{show t} =?= %ref \{k'}"
case lookup k' !(get) of
Just (MkEntry _ name ty (Fn tm)) => unify env mode t !(vappSpine !(eval [] CBN tm) sp')
_ => error fc' "unify failed \{show t} =?= \{show u} [no Fn]\n env is \{show env}"
unifyRef t@(VRef fc k def sp) u = do
debug "expand %ref \{k} \{show sp} =?= \{show u}"
case lookup k !(get) of
Just (MkEntry _ name ty (Fn tm)) => unify env mode !(vappSpine !(eval [] CBN tm) sp) u
_ => error fc "unify failed \{show t} [no Fn] =?= \{show u}\n env is \{show env}"
unifyRef t u = unifyRest t u
unifyVar : Val -> Val -> M UnifyResult
unifyVar t'@(VVar fc k sp) u'@(VVar fc' k' sp') =
if k == k' then unifySpine env mode (k == k') sp sp'
else error fc "Failed to unify \{show t'} and \{show u'}"
unifyVar t'@(VVar fc k [<]) u = case !(tryEval env u) of
Just v => unify env mode t' v
Nothing => error fc "Failed to unify \{show t'} and \{show u}"
unifyVar t u'@(VVar fc k [<]) = case !(tryEval env t) of
Just v => unify env mode v u'
Nothing => error fc "Failed to unify \{show t} and \{show u'}"
unifyVar t u = unifyRef t u
unifyLam : Val -> Val -> M UnifyResult
unifyLam (VLam fc _ _ _ t) (VLam _ _ _ _ t') = do
let fresh = VVar fc (length env) [<]
unify (fresh :: env) mode !(t $$ fresh) !(t' $$ fresh)
unifyLam t (VLam fc' _ _ _ t') = do
debug "ETA \{show t}"
let fresh = VVar fc' (length env) [<]
unify (fresh :: env) mode !(t `vapp` fresh) !(t' $$ fresh)
unifyLam (VLam fc _ _ _ t) t' = do
debug "ETA' \{show t'}"
let fresh = VVar fc (length env) [<]
unify (fresh :: env) mode !(t $$ fresh) !(t' `vapp` fresh)
unifyLam t u = unifyVar t u
unifyMeta : Val -> Val -> M UnifyResult
-- flex/flex
unifyMeta (VMeta fc k sp) (VMeta fc' k' sp') =
if k == k' then unifySpine env mode (k == k') sp sp'
-- TODO, might want to try the other way, too.
else if length sp < length sp'
then solve env k' sp' (VMeta fc k sp) >> pure neutral
else solve env k sp (VMeta fc' k' sp') >> pure neutral
unifyMeta t (VMeta fc' i' sp') = solve env i' sp' t >> pure neutral
unifyMeta (VMeta fc i sp) t' = solve env i sp t' >> pure neutral
unifyMeta t v = unifyLam t v
unifyPattern : Val -> Val -> M UnifyResult
unifyPattern t'@(VVar fc k sp) u'@(VVar fc' k' sp') =
if k == k' then unifySpine env mode (k == k') sp sp'
else case (sp, sp') of
([<],[<]) => if k < k' then pure $ MkResult [(k,u')] else pure $ MkResult [(k',t')]
_ => error fc "Failed to unify \{show t'} and \{show u'}"
unifyPattern (VVar fc k [<]) u = pure $ MkResult[(k, u)]
unifyPattern t (VVar fc k [<]) = pure $ MkResult [(k, t)]
unifyPattern t u = unifyMeta t u
unifyCatch fc ctx ty' ty = do
res <- catchError (unify ctx.env Normal ty' ty) $ \err => do
let names = toList $ map fst ctx.types
debug "fail \{show ty'} \{show ty}"
a <- quote ctx.lvl ty'
b <- quote ctx.lvl ty
let msg = "unification failure: \{errorMsg err}\n failed to unify \{pprint names a}\n with \{pprint names b}\n "
throwError (E fc msg)
case res of
MkResult [] => pure ()
cs => do
-- probably want a unification mode that throws instead of returning constraints
-- TODO need a normalizeHoles, maybe on quote?
debug "fail with constraints \{show cs.constraints}"
a <- quote ctx.lvl ty'
b <- quote ctx.lvl ty
let names = toList $ map fst ctx.types
let msg = "xxunification failure\n failed to unify \{pprint names a}\n with \{pprint names b}"
let msg = msg ++ "\nconstraints \{show cs.constraints}"
throwError (E fc msg)
-- error fc "Unification yields constraints \{show cs.constraints}"
export
freshMeta : Context -> FC -> Val -> MetaKind -> M Tm
freshMeta ctx fc ty kind = do
top <- get
mc <- readIORef top.metaCtx
debug "fresh meta \{show mc.next} : \{show ty} (\{show kind})"
let newmeta = Unsolved fc mc.next ctx ty kind []
writeIORef top.metaCtx $ { next $= S, metas $= (newmeta ::) } mc
-- infinite loop - keeps trying Ord a => Ord (a \x a)
-- when (kind == AutoSolve) $ ignore $ trySolveAuto newmeta
pure $ applyBDs 0 (Meta fc mc.next) ctx.bds
where
-- hope I got the right order here :)
applyBDs : Nat -> Tm -> Vect k BD -> Tm
applyBDs k t [] = t
-- review the order here
applyBDs k t (Bound :: xs) = App emptyFC (applyBDs (S k) t xs) (Bnd emptyFC k)
applyBDs k t (Defined :: xs) = applyBDs (S k) t xs
insert : (ctx : Context) -> Tm -> Val -> M (Tm, Val)
insert ctx tm ty = do
case !(forceMeta ty) of
VPi fc x Auto rig a b => do
m <- freshMeta ctx (getFC tm) a AutoSolve
debug "INSERT Auto \{pprint (names ctx) m} : \{show a}"
debug "TM \{pprint (names ctx) tm}"
mv <- eval ctx.env CBN m
insert ctx (App (getFC tm) tm m) !(b $$ mv)
VPi fc x Implicit rig a b => do
m <- freshMeta ctx (getFC tm) a Normal
debug "INSERT \{pprint (names ctx) m} : \{show a}"
debug "TM \{pprint (names ctx) tm}"
mv <- eval ctx.env CBN m
insert ctx (App (getFC tm) tm m) !(b $$ mv)
va => pure (tm, va)
primType : FC -> QName -> M Val
primType fc nm = case lookup nm !(get) of
Just (MkEntry _ name ty PrimTCon) => pure $ VRef fc name PrimTCon [<]
_ => error fc "Primitive type \{show nm} not in scope"
export
infer : Context -> Raw -> M (Tm, Val)
data Bind = MkBind String Icit Val
Show Bind where
show (MkBind str icit x) = "\{str} \{show icit}"
---------------- Case builder
public export
record Problem where
constructor MkProb
clauses : List Clause
-- I think a pi-type representing the pattern args -> goal, so we're checking
-- We might pull out the pattern abstraction to a separate step and drop pats from clauses.
ty : Val
-- Might have to move this if Check reaches back in...
-- this is kinda sketchy, we can't use it twice at the same depth with the same name.
fresh : {auto ctx : Context} -> String -> String
fresh base = base ++ "$" ++ show (length ctx.env)
-- The result is a casetree, but it's in Tm
export
buildTree : Context -> Problem -> M Tm
-- Updates a clause for INTRO
introClause : String -> Icit -> Clause -> M Clause
introClause nm icit (MkClause fc cons (pat :: pats) expr) =
if icit == getIcit pat then pure $ MkClause fc ((nm, pat) :: cons) pats expr
else if icit == Implicit then pure $ MkClause fc ((nm, PatWild fc Implicit) :: cons) (pat :: pats) expr
else if icit == Auto then pure $ MkClause fc ((nm, PatWild fc Auto) :: cons) (pat :: pats) expr
else error fc "Explicit arg and \{show $ getIcit pat} pattern \{show nm} \{show pat}"
-- handle implicts at end?
introClause nm Implicit (MkClause fc cons [] expr) = pure $ MkClause fc ((nm, PatWild fc Implicit) :: cons) [] expr
introClause nm Auto (MkClause fc cons [] expr) = pure $ MkClause fc ((nm, PatWild fc Auto) :: cons) [] expr
introClause nm icit (MkClause fc cons [] expr) = error fc "Clause size doesn't match"
-- A split candidate looks like x /? Con ...
-- we need a type here. I pulled if off of the
-- pi-type, but do we need metas solved or dependents split?
-- this may dot into a dependent.
findSplit : List Constraint -> Maybe Constraint
findSplit [] = Nothing
-- FIXME look up type, ensure it's a constructor
findSplit (x@(nm, PatCon _ _ _ _ _) :: xs) = Just x
findSplit (x@(nm, PatLit _ val) :: xs) = Just x
findSplit (x :: xs) = findSplit xs
-- ***************
-- right, I think we rewrite the names in the context before running raw and we're good to go?
-- We have stuff like S k /? x, but I think we can back up to whatever the scrutinee variable was?
-- we could pass into build case and use it for (x /? y)
-- TODO, we may need to filter these against the type to rule out
-- impossible cases
getConstructors : Context -> FC -> Val -> M (List (QName, Nat, Tm))
getConstructors ctx scfc (VRef fc nm _ _) = do
names <- lookupTCon nm
traverse lookupDCon names
where
lookupTCon : QName -> M (List QName)
lookupTCon str = case lookup nm !get of
(Just (MkEntry _ name type (TCon names))) => pure names
_ => error scfc "Not a type constructor \{nm}"
lookupDCon : QName -> M (QName, Nat, Tm)
lookupDCon nm = do
case lookup nm !get of
(Just (MkEntry _ name type (DCon k str))) => pure (name, k, type)
Just _ => error fc "Internal Error: \{nm} is not a DCon"
Nothing => error fc "Internal Error: DCon \{nm} not found"
getConstructors ctx scfc tm = error scfc "Can't split - not VRef: \{!(pprint ctx tm)}"
-- Extend environment with fresh variables from a pi-type
-- the pi-type here is the telescope of a constructor
-- return context, remaining type, and list of names
extendPi : Context -> Val -> SnocList Bind -> SnocList Val -> M (Context, Val, List Bind, SnocList Val)
extendPi ctx (VPi x str icit rig a b) nms sc = do
let nm = fresh str -- "pat"
let ctx' = extend ctx nm a
let v = VVar emptyFC (length ctx.env) [<]
tyb <- b $$ v
extendPi ctx' tyb (nms :< MkBind nm icit a) (sc :< VVar x (length ctx.env) [<])
extendPi ctx ty nms sc = pure (ctx, ty, nms <>> [], sc)
-- turn vars into lets for forced values.
-- substitute inside values
-- FIXME we're not going under closures at the moment.
substVal : Nat -> Val -> Val -> Val
substVal k v tm = go tm
where
go : Val -> Val
go (VVar fc j sp) = if j == k then v else (VVar fc j (map go sp))
go (VLet fc nm a b) = VLet fc nm (go a) b
go (VPi fc nm icit rig a b) = VPi fc nm icit rig (go a) b
go (VMeta fc ix sp) = VMeta fc ix (map go sp)
go (VRef fc nm y sp) = VRef fc nm y (map go sp)
go tm = tm
-- FIXME - do I need a Val closure like idris?
-- or env in unify...
-- or quote back
-- go (VLam fc nm sc) = VLam fc nm sc
-- go (VCase x sc xs) = ?rhs_2
-- go (VU x) = ?rhs_7
-- go (VLit x y) = ?rhs_8
-- need to turn k into a ground value
-- TODO rework this to do something better. We've got constraints, and
-- and may need to do proper unification if it's already defined to a value
-- below we're handling the case if it's defined to another var, but not
-- checking for loops.
updateContext : Context -> List (Nat, Val) -> M Context
updateContext ctx [] = pure ctx
updateContext ctx ((k, val) :: cs) =
let ix = lvl2ix (length ctx.env) k in
case getAt ix ctx.env of
(Just (VVar _ k' [<])) =>
if k' /= k
then updateContext ctx ((k',val) :: cs)
else updateContext ({env $= map (substVal k val), bds $= replaceV ix Defined } ctx) cs
(Just val') => do
-- This is fine for Z =?= Z but for other stuff, we probably have to match
info (getFC val) "need to unify \{show val} and \{show val'} or something"
updateContext ctx cs
Nothing => error (getFC val) "INTERNAL ERROR: bad index in updateContext"
--
-- updateContext ({env $= replace ix val, bds $= replaceV ix Defined } ctx) cs
where
replace : Nat -> Val -> List Val -> List Val
replace k x [] = []
replace 0 x (y :: xs) = x :: xs
replace (S k) x (y :: xs) = y :: replace k x xs
replaceV : Nat -> a -> Vect n a -> Vect n a
replaceV k x [] = []
replaceV 0 x (y :: xs) = x :: xs
replaceV (S k) x (y :: xs) = y :: replaceV k x xs
-- ok, so this is a single constructor, CaseAlt
-- return Nothing if dcon doesn't unify with scrut
buildCase : Context -> Problem -> String -> Val -> (QName, Nat, Tm) -> M (Maybe CaseAlt)
buildCase ctx prob scnm scty (dcName, arity, ty) = do
debug "CASE \{scnm} match \{dcName} ty \{pprint (names ctx) ty}"
vty <- eval [] CBN ty
(ctx', ty', vars, sc) <- extendPi ctx (vty) [<] [<]
-- TODO I think we need to figure out what is dotted, maybe
-- the environment manipulation below is sufficient bookkeeping
-- or maybe it's a bad approach.
-- At some point, I'll take a break and review more papers and code,
-- now that I know some of the questions I'm trying to answer.
-- We get unification constraints from matching the data constructors
-- codomain with the scrutinee type
debug "unify dcon cod with scrut\n \{show ty'}\n \{show scty}"
Just res <- catchError(Just <$> unify ctx'.env Pattern ty' scty)
(\err => do
debug "SKIP \{dcName} because unify error \{errorMsg err}"
pure Nothing)
| _ => pure Nothing
-- if the value is already constrained to a different constructor, return Nothing
debug "scrut \{scnm} constrained to \{show $ lookupDef ctx scnm}"
let (VRef _ sctynm _ _) = scty | _ => error (getFC scty) "case split on non-inductive \{show scty}"
case lookupDef ctx scnm of
Just val@(VRef fc nm y sp) =>
if nm /= dcName
then do
debug "SKIP \{dcName} because \{scnm} forced to \{show val}"
pure Nothing
else do
debug "case \{dcName} dotted \{show val}"
when (length vars /= length sp) $ error emptyFC "\{show $ length vars} vars /= \{show $ length sp}"
-- TODO - I think we need to define the context vars to sp via updateContext
let lvl = minus (length ctx'.env) (length vars)
let scons = constrainSpine lvl (sp <>> []) -- REVIEW is this the right order?
ctx' <- updateContext ctx' scons
debug "(dcon \{show dcName} ty \{show ty'} scty \{show scty}"
debug "(dcon \{show dcName}) (vars \{show vars}) clauses were"
for_ prob.clauses $ (\x => debug " \{show x}")
clauses <- mapMaybe id <$> traverse (rewriteClause sctynm vars) prob.clauses
debug "and now:"
for_ clauses $ (\x => debug " \{show x}")
when (length clauses == 0) $ error ctx.ctxFC "Missing case for \{dcName} splitting \{scnm}"
tm <- buildTree ctx' (MkProb clauses prob.ty)
pure $ Just $ CaseCons dcName (map getName vars) tm
_ => do
Right res <- tryError (unify ctx'.env Pattern ty' scty)
| Left err => do
debug "SKIP \{dcName} because unify error \{errorMsg err}"
pure Nothing
-- Constrain the scrutinee's variable to be dcon applied to args
let Just x = findIndex ((==scnm) . fst) ctx'.types
| Nothing => error ctx.ctxFC "\{scnm} not is scope?"
let lvl = lvl2ix (length ctx'.env) (cast x)
let scon : (Nat, Val) = (lvl, VRef ctx.ctxFC dcName (DCon arity dcName) sc)
debug "scty \{show scty}"
debug "UNIFY results \{show res.constraints}"
debug "before types: \{show ctx'.types}"
debug "before env: \{show ctx'.env}"
debug "SC CONSTRAINT: \{show scon}"
-- push the constraints into the environment by turning bind into define
-- Is this kosher? It might be a problem if we've already got metas over
-- this stuff, because it intends to ignore defines.
ctx' <- updateContext ctx' (scon :: res.constraints)
debug "context types: \{show ctx'.types}"
debug "context env: \{show ctx'.env}"
-- What if all of the pattern vars are defined to meta
debug "(dcon \{show dcName} ty \{show ty'} scty \{show scty}"
debug "(dcon \{show dcName}) (vars \{show vars}) clauses were"
for_ prob.clauses $ (\x => debug " \{show x}")
clauses <- mapMaybe id <$> traverse (rewriteClause sctynm vars) prob.clauses
debug "and now:"
for_ clauses $ (\x => debug " \{show x}")
when (length clauses == 0) $ error ctx.ctxFC "Missing case for \{dcName} splitting \{scnm}"
tm <- buildTree ctx' (MkProb clauses prob.ty)
pure $ Just $ CaseCons dcName (map getName vars) tm
where
constrainSpine : Nat -> List Val -> List (Nat, Val)
constrainSpine lvl [] = []
constrainSpine lvl (v :: vs) = (lvl, v) :: constrainSpine (S lvl) vs
getName : Bind -> String
getName (MkBind nm _ _) = nm
-- for each clause in prob, find nm on LHS of some constraint, and
-- "replace" with the constructor and vars.
--
-- This will be:
-- x /? y can probably just leave this
-- x /? D a b c split into three x /? a, y /? b, z /? c
-- x /? E a b drop this clause
-- We get a list of clauses back (a Problem) and then solve that
-- If they all fail, we have a coverage issue. (Assuming the constructor is valid)
makeConstr : List Bind -> List Pattern -> M (List (String, Pattern))
makeConstr [] [] = pure $ []
makeConstr [] (pat :: pats) = error (getFC pat) "too many patterns"
makeConstr ((MkBind nm Implicit x) :: xs) [] = pure $ (nm, PatWild emptyFC Implicit) :: !(makeConstr xs [])
makeConstr ((MkBind nm Auto x) :: xs) [] = pure $ (nm, PatWild emptyFC Auto) :: !(makeConstr xs [])
makeConstr ((MkBind nm Explicit x) :: xs) [] = error ctx.ctxFC "not enough patterns"
makeConstr ((MkBind nm Explicit x) :: xs) (pat :: pats) =
if getIcit pat == Explicit
then pure $ (nm, pat) :: !(makeConstr xs pats)
else error ctx.ctxFC "mismatch between Explicit and \{show $ getIcit pat}"
makeConstr ((MkBind nm icit x) :: xs) (pat :: pats) =
if getIcit pat /= icit -- Implicit/Explicit Implicit/Auto, etc
then pure $ (nm, PatWild (getFC pat) icit) :: !(makeConstr xs (pat :: pats))
else pure $ (nm, pat) :: !(makeConstr xs pats)
-- replace constraint with constraints on parameters, or nothing if non-matching clause
rewriteConstraint : QName -> List Bind -> List Constraint -> List Constraint -> M (Maybe (List Constraint))
rewriteConstraint sctynm vars [] acc = pure $ Just acc
rewriteConstraint sctynm vars (c@(nm, y) :: xs) acc =
if nm == scnm
then case y of
PatVar _ _ s => pure $ Just $ c :: (xs ++ acc)
PatWild _ _ => pure $ Just $ c :: (xs ++ acc)
-- FIXME why don't we hit this (when user puts 'x' for Just 'x')
PatLit fc lit => error fc "Literal \{show lit} in constructor split"
PatCon fc icit nm ys as => if nm == dcName
then case as of
Nothing => pure $ Just $ !(makeConstr vars ys) ++ xs ++ acc
-- putting this in constraints causes it to be renamed scnm -> nm' when we check body.
Just nm' => pure $ Just $ (scnm, (PatVar fc icit nm')) :: !(makeConstr vars ys) ++ xs ++ acc
else do
-- TODO can we check this when we make the PatCon?
case lookup nm !get of
(Just (MkEntry _ name type (DCon k tcname))) =>
if (tcname /= sctynm)
then error fc "Constructor is \{tcname} expected \{sctynm}"
else pure Nothing
Just _ => error fc "Internal Error: \{nm} is not a DCon"
Nothing => error fc "Internal Error: DCon \{nm} not found"
else rewriteConstraint sctynm vars xs (c :: acc)
rewriteClause : QName -> List Bind -> Clause -> M (Maybe Clause)
rewriteClause sctynm vars (MkClause fc cons pats expr) = do
Just cons <- rewriteConstraint sctynm vars cons [] | _ => pure Nothing
pure $ Just $ MkClause fc cons pats expr
export
splitArgs : Raw -> List (Raw, Icit) -> (Raw, List (Raw, Icit))
splitArgs (RApp fc t u icit) args = splitArgs t ((u, icit) :: args)
splitArgs tm args = (tm, args)
mkPat : TopContext -> (Raw, Icit) -> M Pattern
mkPat top (RAs fc as tm, icit) =
case !(mkPat top (tm, icit)) of
(PatCon fc icit nm args Nothing) => pure $ PatCon fc icit nm args (Just as)
(PatCon fc icit nm args _) => error fc "Double as pattern \{show tm}"
t => error fc "Can't put as on non-constructor \{show tm}"
mkPat top (tm, icit) = do
case splitArgs tm [] of
((RVar fc nm), b) => case lookupRaw nm top of
(Just (MkEntry _ name type (DCon k str))) =>
-- TODO check arity, also figure out why we need reverse
pure $ PatCon fc icit name !(traverse (mkPat top) b) Nothing
-- This fires when a global is shadowed by a pattern var
-- Just _ => error (getFC tm) "\{show nm} is not a data constructor"
_ => case b of
[] => pure $ PatVar fc icit nm
_ => error (getFC tm) "patvar applied to args"
((RImplicit fc), []) => pure $ PatWild fc icit
((RImplicit fc), _) => error fc "implicit pat can't be applied to arguments"
((RLit fc lit), []) => pure $ PatLit fc lit
((RLit fc y), b) => error fc "lit cannot be applied to arguments"
(a,b) => error (getFC a) "expected pat var or constructor, got \{show a}"
export
makeClause : TopContext -> (Raw, Raw) -> M Clause
makeClause top (lhs, rhs) = do
let (nm, args) = splitArgs lhs []
pats <- traverse (mkPat top) args
pure $ MkClause (getFC lhs) [] pats rhs
-- we'll want both check and infer, we're augmenting a context
-- so probably a continuation:
-- Context -> List Decl -> (Context -> M a) -> M a
checkWhere : Context -> List Decl -> Raw -> Val -> M Tm
checkWhere ctx decls body ty = do
-- we're going to be very proscriptive here
let (TypeSig sigFC [name] rawtype :: decls) = decls
| x :: _ => error (getFC x) "expected type signature"
| _ => check ctx body ty
funTy <- check ctx rawtype (VU sigFC)
debug "where clause \{name} : \{pprint (names ctx) funTy}"
let (Def defFC name' clauses :: decls') = decls
| x :: _ => error (getFC x) "expected function definition"
| _ => error sigFC "expected function definition after this signature"
unless (name == name') $ error defFC "Expected def for \{name}"
-- REVIEW is this right, cribbed from my top level code
top <- get
clauses' <- traverse (makeClause top) clauses
vty <- eval ctx.env CBN funTy
debug "\{name} vty is \{show vty}"
let ctx' = extend ctx name vty
-- if I lift, I need to namespace it, add args, and add args when
-- calling locally
-- context could hold a Name -> Val (not Tm because levels) to help with that
-- e.g. "go" -> (VApp ... (VApp (VRef "ns.go") ...)
-- But I'll attempt letrec first
tm <- buildTree ({ ctxFC := defFC} ctx') (MkProb clauses' vty)
vtm <- eval ctx'.env CBN tm
-- Should we run the rest with the definition in place?
-- I'm wondering if switching from bind to define will mess with metas
-- let ctx' = define ctx name vtm vty
pure $ LetRec sigFC name funTy tm !(checkWhere ctx' decls' body ty)
checkDone : Context -> List (String, Pattern) -> Raw -> Val -> M Tm
checkDone ctx [] body ty = do
debug "DONE-> check body \{show body} at \{show ty}"
-- TODO better dump context function
debugM $ showCtx ctx
-- Hack to try to get Combinatory working
-- we're trying to subst in solutions here.
env' <- for ctx.env $ \ val => do
ty <- quote (length ctx.env) val
-- This is not getting vars under lambdas
eval ctx.env CBV ty
types' <- for ctx.types $ \case
(nm,ty) => do
nty <- quote (length env') ty
ty' <- eval env' CBV nty
pure (nm, ty')
let ctx = { env := env', types := types' } ctx
debug "AFTER"
debugM $ showCtx ctx
-- I'm running an eval here to run case statements that are
-- unblocked by lets in the env. (Tree.newt:cmp)
-- The case eval code only works in the Tm -> Val case at the moment.
-- we don't have anything like `vapp` for case
ty <- quote (length ctx.env) ty
ty <- eval ctx.env CBN ty
debug "check at \{show ty}"
got <- check ctx body ty
debug "DONE<- got \{pprint (names ctx) got}"
pure got
checkDone ctx ((x, PatWild _ _) :: xs) body ty = checkDone ctx xs body ty
checkDone ctx ((nm, (PatVar _ _ nm')) :: xs) body ty = checkDone ({ types $= rename } ctx) xs body ty
where
rename : Vect n (String, Val) -> Vect n (String, Val)
rename [] = []
rename ((name, ty) :: xs) =
if name == nm
then (nm', ty) :: xs
else (name, ty) :: rename xs
checkDone ctx ((x, pat) :: xs) body ty = error (getFC pat) "stray constraint \{x} /? \{show pat}"
-- need to run constructors, then run default
-- wild/var can come before 'x' so we need a list first
getLits : String -> List Clause -> List Literal
getLits nm [] = []
getLits nm ((MkClause fc cons pats expr) :: cs) = case find ((nm==) . fst) cons of
Just (_, (PatLit _ lit)) => lit :: getLits nm cs
_ => getLits nm cs
-- then build a lit case for each of those
buildLitCase : Context -> Problem -> FC -> String -> Val -> Literal -> M CaseAlt
buildLitCase ctx prob fc scnm scty lit = do
-- Constrain the scrutinee's variable to be lit value
let Just ix = findIndex ((==scnm) . fst) ctx.types
| Nothing => error ctx.ctxFC "\{scnm} not is scope?"
let lvl = lvl2ix (length ctx.env) (cast ix)
let scon : (Nat, Val) = (lvl, VLit fc lit)
ctx' <- updateContext ctx [scon]
let clauses = mapMaybe rewriteClause prob.clauses
when (length clauses == 0) $ error ctx.ctxFC "Missing case for \{show lit} splitting \{scnm}"
tm <- buildTree ctx' (MkProb clauses prob.ty)
pure $ CaseLit lit tm
where
-- FIXME - thread in M for errors
-- replace constraint with constraints on parameters, or nothing if non-matching clause
rewriteConstraint : List Constraint -> List Constraint -> Maybe (List Constraint)
rewriteConstraint [] acc = Just acc
rewriteConstraint (c@(nm, y) :: xs) acc =
if nm == scnm
then case y of
PatVar _ _ s => Just $ c :: (xs ++ acc)
PatWild _ _ => Just $ c :: (xs ++ acc)
PatLit fc lit' => if lit' == lit then Just $ (xs ++ acc) else Nothing
PatCon _ _ str ys as => Nothing -- error matching lit against constructor
else rewriteConstraint xs (c :: acc)
rewriteClause : Clause -> Maybe Clause
rewriteClause (MkClause fc cons pats expr) = pure $ MkClause fc !(rewriteConstraint cons []) pats expr
buildLitCases : Context -> Problem -> FC -> String -> Val -> M (List CaseAlt)
buildLitCases ctx prob fc scnm scty = do
let lits = nub $ getLits scnm prob.clauses
alts <- traverse (buildLitCase ctx prob fc scnm scty) lits
-- TODO build default case
-- run getLits
-- buildLitCase for each
let defclauses = filter isDefault prob.clauses
when (length defclauses == 0) $ error fc "no default for literal slot on \{show scnm}"
tm <- buildTree ctx (MkProb defclauses prob.ty)
pure $ alts ++ [ CaseDefault tm ]
where
isDefault : Clause -> Bool
isDefault cl = case find ((==scnm) . fst) cl.cons of
Just (_, (PatVar _ _ _)) => True
Just (_, (PatWild _ _)) => True
Nothing => True
_ => False
-- TODO - figure out if these need to be in Prelude or have a special namespace
-- If we lookupRaw "String", we could get different answers in different contexts.
-- maybe Hardwire this one
stringType : QName
stringType = QN ["Prim"] "String"
intType = QN ["Prim"] "Int"
charType = QN ["Prim"] "Char"
litTyName : Literal -> QName
litTyName (LString str) = stringType
litTyName (LInt i) = intType
litTyName (LChar c) = charType
renameContext : String -> String -> Context -> Context
renameContext from to ctx = { types $= go } ctx
where
go : Vect n (String,Val) -> Vect n (String,Val)
go Nil = Nil
go ((a,b) :: types) = if a == from then (to,b) :: types else (a,b) :: go types
-- This process is similar to extendPi, but we need to stop
-- if one clause is short on patterns.
buildTree ctx (MkProb [] ty) = error emptyFC "no clauses"
buildTree ctx prob@(MkProb ((MkClause fc cons (x :: xs) expr) :: cs) (VPi _ str icit rig a b)) = do
let l = length ctx.env
let nm = fresh str -- "pat"
let ctx' = extend ctx nm a
-- type of the rest
clauses <- traverse (introClause nm icit) prob.clauses
-- REVIEW fc from a pat?
vb <- b $$ VVar fc l [<]
Lam fc nm icit rig <$> buildTree ctx' ({ clauses := clauses, ty := vb } prob)
buildTree ctx prob@(MkProb ((MkClause fc cons pats@(x :: xs) expr) :: cs) ty) =
error fc "Extra pattern variables \{show pats}"
-- need to find some name we can split in (x :: xs)
-- so LHS of constraint is name (or VVar - if we do Val)
-- then run the split
-- some of this is copied into check
buildTree ctx prob@(MkProb ((MkClause fc constraints [] expr) :: cs) ty) = do
debug "buildTree \{show constraints} \{show expr}"
let Just (scnm, pat) = findSplit constraints
| _ => do
debug "checkDone \{show constraints}"
checkDone ctx constraints expr ty
debug "SPLIT on \{scnm} because \{show pat} \{show $ getFC pat}"
let Just (sctm, scty) = lookupName ctx scnm
| _ => error fc "Internal Error: can't find \{scnm} in environment"
-- REVIEW We probably need to know this is a VRef before we decide to split on this slot..
scty' <- unlet ctx.env scty >>= forceType ctx.env
-- TODO attempting to pick up Autos that could have been solved immediately
-- If we try on creation, we're looping at the moment, because of the possibility
-- of Ord a -> Ord b -> Ord (a \x b). Need to cut earlier when solving or switch to
-- Idris method...
scty' <- case scty' of
(VMeta fc1 ix sp) => do
case !(lookupMeta ix) of
(Solved _ k t) => forceType ctx.env scty'
(Unsolved _ k xs _ _ _) => do
top <- get
mc <- readIORef top.metaCtx
ignore $ solveAutos 0
forceType ctx.env scty'
_ => pure scty'
case pat of
PatCon fc _ _ _ as => do
-- expand vars that may be solved, eval top level functions
debug "EXP \{show scty} -> \{show scty'}"
-- this is per the paper, but it would be nice to coalesce
-- default cases
cons <- getConstructors ctx (getFC pat) scty'
debug "CONS \{show $ map fst cons}"
alts <- traverse (buildCase ctx prob scnm scty') cons
debug "GOTALTS \{show alts}"
when (length (catMaybes alts) == 0) $ error (fc) "no alts for \{show scty'}"
pure $ Case fc sctm (catMaybes alts)
PatLit fc v => do
let tyname = litTyName v
case scty' of
(VRef fc1 nm x sp) => when (nm /= tyname) $ error fc "expected \{show scty} and got \{tyname}"
_ => error fc "expected \{show scty} and got \{tyname}"
-- need to run through all of the PatLits in this slot and then find a fallback
-- walk the list of patterns, stop if we hit a PatVar / PatWild, fail if we don't
alts <- buildLitCases ctx prob fc scnm scty
pure $ Case fc sctm alts
pat => error (getFC pat) "Internal error - tried to split on \{show pat}"
showDef : Context -> List String -> Nat -> Val -> M String
showDef ctx names n v@(VVar _ n' [<]) = if n == n' then pure "" else pure "= \{pprint names !(quote ctx.lvl v)}"
showDef ctx names n v = pure "= \{pprint names !(quote ctx.lvl v)}"
-- desugar do
undo : FC -> List DoStmt -> M Raw
undo prev [] = error prev "do block must end in expression"
undo prev ((DoExpr fc tm) :: Nil) = pure tm
-- TODO decide if we want to use >> or just >>=
undo prev ((DoExpr fc tm) :: xs) = pure $ RApp fc (RApp fc (RVar fc "_>>=_") tm Explicit) (RLam fc (BI fc "_" Explicit Many) !(undo fc xs)) Explicit
-- undo ((DoExpr fc tm) :: xs) = pure $ RApp fc (RApp fc (RVar fc "_>>_") tm Explicit) !(undo xs) Explicit
undo prev ((DoLet fc nm tm) :: xs) = RLet fc nm (RImplicit fc) tm <$> undo fc xs
undo prev ((DoArrow fc left@(RVar fc' nm) right []) :: xs) =
case lookupRaw nm !get of
Just _ => do
let nm = "$sc"
rest <- pure $ RCase fc (RVar fc nm) [MkAlt left !(undo fc xs)]
pure $ RApp fc (RApp fc (RVar fc "_>>=_") right Explicit)
(RLam fc (BI fc nm Explicit Many) rest) Explicit
Nothing =>
pure $ RApp fc (RApp fc (RVar fc "_>>=_") right Explicit)
(RLam fc (BI fc' nm Explicit Many) !(undo fc xs)) Explicit
undo prev ((DoArrow fc left right alts) :: xs) = do
let nm = "$sc"
rest <- pure $ RCase fc (RVar fc nm) (MkAlt left !(undo fc xs) :: alts)
pure $ RApp fc (RApp fc (RVar fc "_>>=_") right Explicit)
(RLam fc (BI fc nm Explicit Many) rest) Explicit
check ctx tm ty = case (tm, !(forceType ctx.env ty)) of
(RWhere fc decls body, ty) => checkWhere ctx (collectDecl decls) body ty
(RIf fc a b c, ty) =>
let tm' = RCase fc a [ MkAlt (RVar (getFC b) "True") b, MkAlt (RVar (getFC c) "False") c ] in
check ctx tm' ty
(RDo fc stmts, ty) => check ctx !(undo fc stmts) ty
(RCase fc rsc alts, ty) => do
(sc, scty) <- infer ctx rsc
scty <- forceMeta scty
debug "SCTM \{pprint (names ctx) sc}"
debug "SCTY \{show scty}"
let scnm = fresh "sc"
top <- get
clauses <- traverse (\(MkAlt pat rawRHS) => pure $ MkClause (getFC pat) [(scnm, !(mkPat top (pat, Explicit)))] [] rawRHS ) alts
-- buildCase expects scrutinee to be a name in the context, so we need to let it.
-- if it's a Bnd and not shadowed we could skip the let, but that's messy.
let ctx' = withPos (extend ctx scnm scty) (getFC tm)
pure $ Let fc scnm sc !(buildTree ctx' $ MkProb clauses ty)
-- rendered in ProcessDecl
(RHole fc, ty) => freshMeta ctx fc ty User
(t@(RLam fc (BI _ nm icit _) tm), ty@(VPi fc' nm' icit' rig a b)) => do
debug "icits \{nm} \{show icit} \{nm'} \{show icit'}"
if icit == icit' then do
let var = VVar fc (length ctx.env) [<]
let ctx' = extend ctx nm a
tm' <- check ctx' tm !(b $$ var)
pure $ Lam fc nm icit rig tm'
else if icit' /= Explicit then do
let var = VVar fc (length ctx.env) [<]
ty' <- b $$ var
-- use nm' here if we want them automatically in scope
sc <- check (extend ctx nm' a) t ty'
pure $ Lam fc nm' icit rig sc
else
error fc "Icity issue checking \{show t} at \{show ty}"
(t@(RLam _ (BI fc nm icit quant) tm), ty) =>
error fc "Expected pi type, got \{!(prvalCtx ty)}"
(RLet fc nm ty v sc, rty) => do
ty' <- check ctx ty (VU emptyFC)
vty <- eval ctx.env CBN ty'
v' <- check ctx v vty
vv <- eval ctx.env CBN v'
let ctx' = define ctx nm vv vty
sc' <- check ctx' sc rty
pure $ Let fc nm v' sc'
(RImplicit fc, ty) => freshMeta ctx fc ty Normal
(tm, ty@(VPi fc nm' Implicit rig a b)) => do
let names = toList $ map fst ctx.types
debug "XXX edge case add implicit lambda {\{nm'} : \{show a}} to \{show tm} "
let var = VVar fc (length ctx.env) [<]
ty' <- b $$ var
debugM $ pure "XXX ty' is \{!(prvalCtx {ctx=(extend ctx nm' a)} ty')}"
sc <- check (extend ctx nm' a) tm ty'
pure $ Lam (getFC tm) nm' Implicit rig sc
(tm, ty@(VPi fc nm' Auto rig a b)) => do
let names = toList $ map fst ctx.types
debug "XXX edge case add auto lambda {\{nm'} : \{show a}} to \{show tm} "
let var = VVar fc (length ctx.env) [<]
ty' <- b $$ var
debugM $ pure "XXX ty' is \{!(prvalCtx {ctx=(extend ctx nm' a)} ty')}"
sc <- check (extend ctx nm' a) tm ty'
pure $ Lam (getFC tm) nm' Auto rig sc
(tm,ty) => do
(tm', ty') <- infer ctx tm
(tm', ty') <- insert ctx tm' ty'
let names = toList $ map fst ctx.types
debug "INFER \{show tm} to (\{pprint names tm'} : \{show ty'}) expect \{show ty}"
unifyCatch (getFC tm) ctx ty' ty
pure tm'
infer ctx (RVar fc nm) = go 0 ctx.types
where
go : Nat -> Vect n (String, Val) -> M (Tm, Val)
go i [] = case lookupRaw nm !(get) of
Just (MkEntry _ name ty def) => do
debug "lookup \{name} as \{show def}"
pure (Ref fc name def, !(eval [] CBN ty))
Nothing => error fc "\{show nm} not in scope"
go i ((x, ty) :: xs) = if x == nm then pure $ (Bnd fc i, ty)
else go (i + 1) xs
-- FIXME tightens up output but hardcodes a name
-- infer ctx (RApp fc (RVar _ "_$_") u icit) = infer ctx u
infer ctx (RApp fc t u icit) = do
-- If the app is explicit, add any necessary metas
(icit, t, tty) <- case the Icit icit of
Explicit => do
(t, tty) <- infer ctx t
(t, tty) <- insert ctx t tty
pure (Explicit, t, tty)
Implicit => do
(t, tty) <- infer ctx t
pure (Implicit, t, tty)
Auto => do
(t, tty) <- infer ctx t
pure (Auto, t, tty)
(a,b) <- case !(forceMeta tty) of
(VPi fc' str icit' rig a b) => if icit' == icit then pure (a,b)
else error fc "IcitMismatch \{show icit} \{show icit'}"
-- If it's not a VPi, try to unify it with a VPi
-- TODO test case to cover this.
tty => do
debug "unify PI for \{show tty}"
a <- eval ctx.env CBN !(freshMeta ctx fc (VU emptyFC) Normal)
b <- MkClosure ctx.env <$> freshMeta (extend ctx ":ins" a) fc (VU emptyFC) Normal
-- FIXME - I had to guess Many here. What are the side effects?
unifyCatch fc ctx tty (VPi fc ":ins" icit Many a b)
pure (a,b)
u <- check ctx u a
pure (App fc t u, !(b $$ !(eval ctx.env CBN u)))
infer ctx (RU fc) = pure (UU fc, VU fc) -- YOLO
infer ctx (RPi _ (BI fc nm icit quant) ty ty2) = do
ty' <- check ctx ty (VU fc)
vty' <- eval ctx.env CBN ty'
ty2' <- check (extend ctx nm vty') ty2 (VU fc)
pure (Pi fc nm icit quant ty' ty2', (VU fc))
infer ctx (RLet fc nm ty v sc) = do
ty' <- check ctx ty (VU emptyFC)
vty <- eval ctx.env CBN ty'
v' <- check ctx v vty
vv <- eval ctx.env CBN v'
let ctx' = define ctx nm vv vty
(sc',scty) <- infer ctx' sc
pure $ (Let fc nm v' sc', scty)
infer ctx (RAnn fc tm rty) = do
ty <- check ctx rty (VU fc)
vty <- eval ctx.env CBN ty
tm <- check ctx tm vty
pure (tm, vty)
infer ctx (RLam _ (BI fc nm icit quant) tm) = do
a <- freshMeta ctx fc (VU emptyFC) Normal >>= eval ctx.env CBN
let ctx' = extend ctx nm a
(tm', b) <- infer ctx' tm
debug "make lam for \{show nm} scope \{pprint (names ctx) tm'} : \{show b}"
pure $ (Lam fc nm icit quant tm', VPi fc nm icit quant a $ MkClosure ctx.env !(quote (S ctx.lvl) b))
infer ctx (RImplicit fc) = do
ty <- freshMeta ctx fc (VU emptyFC) Normal
vty <- eval ctx.env CBN ty
tm <- freshMeta ctx fc vty Normal
pure (tm, vty)
infer ctx (RLit fc (LString str)) = pure (Lit fc (LString str), !(primType fc stringType))
infer ctx (RLit fc (LInt i)) = pure (Lit fc (LInt i), !(primType fc intType))
infer ctx (RLit fc (LChar c)) = pure (Lit fc (LChar c), !(primType fc charType))
infer ctx (RAs fc _ _) = error fc "@ can only be used in patterns"
infer ctx tm = error (getFC tm) "Implement infer \{show tm}"