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Idris-dev/src/Core/TT.hs
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1{-# LANGUAGE MultiParamTypeClasses, FunctionalDependencies, DeriveFunctor #-}
3{-| TT is the core language of Idris. The language has:
5 * Full dependent types
7 * A hierarchy of universes, with cumulativity: Type : Type1, Type1 : Type2, ...
9 * Pattern matching letrec binding
11 * (primitive types defined externally)
13 Some technical stuff:
15 * Typechecker is kept as simple as possible - no unification, just a checker for incomplete terms.
17 * We have a simple collection of tactics which we use to elaborate source
18 programs with implicit syntax into fully explicit terms.
19-}
21module Core.TT where
23import Control.Monad.State
24import Debug.Trace
25import qualified Data.Map as Map
26import Data.Char
27import Data.List
28import qualified Data.Binary as B
29import Data.Binary hiding (get, put)
31import Util.Pretty hiding (Str)
33data Option = TTypeInTType
34 | CheckConv
35 deriving Eq
37-- | Source location. These are typically produced by the parser 'Idris.Parser.pfc'
38data FC = FC { fc_fname :: String, -- ^ Filename
39 fc_line :: Int -- ^ Line number
40 }
41 deriving Eq
42{-!
43deriving instance Binary FC
44!-}
46instance Sized FC where
47 size (FC f l) = 1 + length f
49instance Show FC where
50 show (FC f l) = f ++ ":" ++ show l
52data Err = Msg String
53 | InternalMsg String
54 | CantUnify Bool Term Term Err [(Name, Type)] Int
55 -- Int is 'score' - how much we did unify
56 -- Bool indicates recoverability, True indicates more info may make
57 -- unification succeed
58 | InfiniteUnify Name Term [(Name, Type)]
59 | CantConvert Term Term [(Name, Type)]
60 | NonFunctionType Term Term
61 | CantIntroduce Term
62 | NoSuchVariable Name
63 | NoTypeDecl Name
64 | NotInjective Term Term Term
65 | CantResolve Term
66 | CantResolveAlts [String]
67 | IncompleteTerm Term
68 | UniverseError
69 | ProgramLineComment
70 | Inaccessible Name
71 | NonCollapsiblePostulate Name
72 | AlreadyDefined Name
73 | ProofSearchFail Err
74 | NoRewriting Term
75 | At FC Err
76 | ProviderError String
77 deriving Eq
79instance Sized Err where
80 size (Msg msg) = length msg
81 size (InternalMsg msg) = length msg
82 size (CantUnify _ left right err _ score) = size left + size right + size err
83 size (InfiniteUnify _ right _) = size right
84 size (CantConvert left right _) = size left + size right
85 size (NoSuchVariable name) = size name
86 size (NoTypeDecl name) = size name
87 size (NotInjective l c r) = size l + size c + size r
88 size (CantResolve trm) = size trm
89 size (NoRewriting trm) = size trm
90 size (CantResolveAlts _) = 1
91 size (IncompleteTerm trm) = size trm
92 size UniverseError = 1
93 size ProgramLineComment = 1
94 size (At fc err) = size fc + size err
95 size (ProviderError msg) = length msg
96 size _ = 1
98score :: Err -> Int
99score (CantUnify _ _ _ m _ s) = s + score m
100score (CantResolve _) = 20
101score (NoSuchVariable _) = 1000
102score (ProofSearchFail _) = 10000
103score _ = 0
105instance Show Err where
106 show (Msg s) = s
107 show (InternalMsg s) = "Internal error: " ++ show s
108 show (CantUnify _ l r e sc i) = "CantUnify " ++ show l ++ " " ++ show r ++ " "
109 ++ show e ++ " in " ++ show sc ++ " " ++ show i
110 show (Inaccessible n) = show n ++ " is not an accessible pattern variable"
111 show (ProviderError msg) = "Type provider error: " ++ msg
112 show _ = "Error"
114instance Pretty Err where
115 pretty (Msg m) = text m
116 pretty (CantUnify _ l r e _ i) =
117 if size l + size r > breakingSize then
118 text "Cannot unify" <+> colon $$
119 nest nestingSize (pretty l <+> text "and" <+> pretty r) $$
120 nest nestingSize (text "where" <+> pretty e <+> text "with" <+> (text . show $ i))
121 else
122 text "Cannot unify" <+> colon <+> pretty l <+> text "and" <+> pretty r $$
123 nest nestingSize (text "where" <+> pretty e <+> text "with" <+> (text . show $ i))
124 pretty (ProviderError msg) = text msg
125 pretty _ = text "Error"
127data TC a = OK a
128 | Error Err
129 deriving (Eq, Functor)
131instance Pretty a => Pretty (TC a) where
132 pretty (OK ok) = pretty ok
133 pretty (Error err) =
134 if size err > breakingSize then
135 text "Error" <+> colon $$ (nest nestingSize $ pretty err)
136 else
137 text "Error" <+> colon <+> pretty err
139instance Show a => Show (TC a) where
140 show (OK x) = show x
141 show (Error str) = "Error: " ++ show str
143-- at some point, this instance should also carry type checking options
144-- (e.g. Type:Type)
146instance Monad TC where
147 return = OK
148 x >>= k = case x of
149 OK v -> k v
150 Error e -> Error e
151 fail e = Error (InternalMsg e)
153tfail :: Err -> TC a
154tfail e = Error e
156trun :: FC -> TC a -> TC a
157trun fc (OK a) = OK a
158trun fc (Error e) = Error (At fc e)
160instance MonadPlus TC where
161 mzero = fail "Unknown error"
162 (OK x) `mplus` _ = OK x
163 _ `mplus` (OK y) = OK y
164 err `mplus` _ = err
166discard :: Monad m => m a -> m ()
167discard f = f >> return ()
169showSep :: String -> [String] -> String
170showSep sep [] = ""
171showSep sep [x] = x
172showSep sep (x:xs) = x ++ sep ++ showSep sep xs
174pmap f (x, y) = (f x, f y)
176traceWhen True msg a = trace msg a
177traceWhen False _ a = a
179-- RAW TERMS ----------------------------------------------------------------
181-- | Names are hierarchies of strings, describing scope (so no danger of
182-- duplicate names, but need to be careful on lookup).
183data Name = UN String -- ^ User-provided name
184 | NS Name [String] -- ^ Root, namespaces
185 | MN Int String -- ^ Machine chosen names
186 | NErased -- ^ Name of somethng which is never used in scope
187 deriving (Eq, Ord)
188{-!
189deriving instance Binary Name
190!-}
192instance Sized Name where
193 size (UN n) = 1
194 size (NS n els) = 1 + length els
195 size (MN i n) = 1
196 size NErased = 1
198instance Pretty Name where
199 pretty (UN n) = text n
200 pretty (NS n s) = pretty n
201 pretty (MN i s) = lbrace <+> text s <+> (text . show $ i) <+> rbrace
203instance Show Name where
204 show (UN n) = n
205 show (NS n s) = showSep "." (reverse s) ++ "." ++ show n
206 show (MN i s) = "{" ++ s ++ show i ++ "}"
207 show NErased = "_"
209-- |Contexts allow us to map names to things. A root name maps to a collection
210-- of things in different namespaces with that name.
211type Ctxt a = Map.Map Name (Map.Map Name a)
212emptyContext = Map.empty
214tcname (UN ('@':_)) = True
215tcname (NS n _) = tcname n
216tcname _ = False
218implicitable (NS n _) = implicitable n
219implicitable (UN (x:xs)) = isLower x
220implicitable _ = False
222nsroot (NS n _) = n
223nsroot n = n
225addDef :: Name -> a -> Ctxt a -> Ctxt a
226addDef n v ctxt = case Map.lookup (nsroot n) ctxt of
227 Nothing -> Map.insert (nsroot n)
228 (Map.insert n v Map.empty) ctxt
229 Just xs -> Map.insert (nsroot n)
230 (Map.insert n v xs) ctxt
232{-| Look up a name in the context, given an optional namespace.
233 The name (n) may itself have a (partial) namespace given.
235 Rules for resolution:
237 - if an explicit namespace is given, return the names which match it. If none
238 match, return all names.
240 - if the name has has explicit namespace given, return the names which match it
241 and ignore the given namespace.
243 - otherwise, return all names.
245-}
247lookupCtxtName :: Maybe [String] -> Name -> Ctxt a -> [(Name, a)]
248lookupCtxtName nspace n ctxt = case Map.lookup (nsroot n) ctxt of
249 Just xs -> filterNS (Map.toList xs)
250 Nothing -> []
251 where
252 filterNS [] = []
253 filterNS ((found, v) : xs)
254 | nsmatch n found = (found, v) : filterNS xs
255 | otherwise = filterNS xs
257 nsmatch (NS n ns) (NS p ps) = ns `isPrefixOf` ps
258 nsmatch (NS _ _) _ = False
259 nsmatch looking found = True
261lookupCtxt :: Maybe [String] -> Name -> Ctxt a -> [a]
262lookupCtxt ns n ctxt = map snd (lookupCtxtName ns n ctxt)
264updateDef :: Name -> (a -> a) -> Ctxt a -> Ctxt a
265updateDef n f ctxt
266 = let ds = lookupCtxtName Nothing n ctxt in
267 foldr (\ (n, t) c -> addDef n (f t) c) ctxt ds
269toAlist :: Ctxt a -> [(Name, a)]
270toAlist ctxt = let allns = map snd (Map.toList ctxt) in
271 concat (map (Map.toList) allns)
273addAlist :: Show a => [(Name, a)] -> Ctxt a -> Ctxt a
274addAlist [] ctxt = ctxt
275addAlist ((n, tm) : ds) ctxt = addDef n tm (addAlist ds ctxt)
277data Const = I Int | BI Integer | Fl Double | Ch Char | Str String
278 | IType | BIType | FlType | ChType | StrType
280 | B8 Word8 | B16 Word16 | B32 Word32 | B64 Word64
281 | B8Type | B16Type | B32Type | B64Type
283 | PtrType | VoidType | Forgot
284 deriving (Eq, Ord)
285{-!
286deriving instance Binary Const
287!-}
289instance Sized Const where
290 size _ = 1
292instance Pretty Const where
293 pretty (I i) = text . show $ i
294 pretty (BI i) = text . show $ i
295 pretty (Fl f) = text . show $ f
296 pretty (Ch c) = text . show $ c
297 pretty (Str s) = text s
298 pretty IType = text "Int"
299 pretty BIType = text "BigInt"
300 pretty FlType = text "Float"
301 pretty ChType = text "Char"
302 pretty StrType = text "String"
303 pretty PtrType = text "Ptr"
304 pretty VoidType = text "Void"
305 pretty Forgot = text "Forgot"
306 pretty B8Type = text "Bits8"
307 pretty B16Type = text "Bits16"
308 pretty B32Type = text "Bits32"
309 pretty B64Type = text "Bits64"
311data Raw = Var Name
312 | RBind Name (Binder Raw) Raw
313 | RApp Raw Raw
314 | RType
315 | RForce Raw
316 | RConstant Const
317 deriving (Show, Eq)
319instance Sized Raw where
320 size (Var name) = 1
321 size (RBind name bind right) = 1 + size bind + size right
322 size (RApp left right) = 1 + size left + size right
323 size RType = 1
324 size (RForce raw) = 1 + size raw
325 size (RConstant const) = size const
327instance Pretty Raw where
328 pretty = text . show
330{-!
331deriving instance Binary Raw
332!-}
334-- | All binding forms are represented in a unform fashion.
335data Binder b = Lam { binderTy :: b {-^ type annotation for bound variable-}}
336 | Pi { binderTy :: b }
337 | Let { binderTy :: b,
338 binderVal :: b {-^ value for bound variable-}}
339 | NLet { binderTy :: b,
340 binderVal :: b }
341 | Hole { binderTy :: b}
342 | GHole { binderTy :: b}
343 | Guess { binderTy :: b,
344 binderVal :: b }
345 | PVar { binderTy :: b }
346 | PVTy { binderTy :: b }
347 deriving (Show, Eq, Ord, Functor)
348{-!
349deriving instance Binary Binder
350!-}
352instance Sized a => Sized (Binder a) where
353 size (Lam ty) = 1 + size ty
354 size (Pi ty) = 1 + size ty
355 size (Let ty val) = 1 + size ty + size val
356 size (NLet ty val) = 1 + size ty + size val
357 size (Hole ty) = 1 + size ty
358 size (GHole ty) = 1 + size ty
359 size (Guess ty val) = 1 + size ty + size val
360 size (PVar ty) = 1 + size ty
361 size (PVTy ty) = 1 + size ty
363fmapMB :: Monad m => (a -> m b) -> Binder a -> m (Binder b)
364fmapMB f (Let t v) = liftM2 Let (f t) (f v)
365fmapMB f (NLet t v) = liftM2 NLet (f t) (f v)
366fmapMB f (Guess t v) = liftM2 Guess (f t) (f v)
367fmapMB f (Lam t) = liftM Lam (f t)
368fmapMB f (Pi t) = liftM Pi (f t)
369fmapMB f (Hole t) = liftM Hole (f t)
370fmapMB f (GHole t) = liftM GHole (f t)
371fmapMB f (PVar t) = liftM PVar (f t)
372fmapMB f (PVTy t) = liftM PVTy (f t)
374raw_apply :: Raw -> [Raw] -> Raw
375raw_apply f [] = f
376raw_apply f (a : as) = raw_apply (RApp f a) as
378raw_unapply :: Raw -> (Raw, [Raw])
379raw_unapply t = ua [] t where
380 ua args (RApp f a) = ua (a:args) f
381 ua args t = (t, args)
383data RawFun = RawFun { rtype :: Raw,
384 rval :: Raw
385 }
386 deriving Show
388data RawDatatype = RDatatype Name Raw [(Name, Raw)]
389 deriving Show
391data RDef = RFunction RawFun
392 | RConst Raw
393 | RData RawDatatype
394 deriving Show
396type RProgram = [(Name, RDef)]
398-- WELL TYPED TERMS ---------------------------------------------------------
400-- | Universe expressions for universe checking
401data UExp = UVar Int -- ^ universe variable
402 | UVal Int -- ^ explicit universe level
403 deriving (Eq, Ord)
405instance Sized UExp where
406 size _ = 1
408-- We assume that universe levels have been checked, so anything external
409-- can just have the same universe variable and we won't get any new
410-- cycles.
412instance Binary UExp where
413 put x = return ()
414 get = return (UVar (-1))
416instance Show UExp where
417 show (UVar x) | x < 26 = [toEnum (x + fromEnum 'a')]
418 | otherwise = toEnum ((x `mod` 26) + fromEnum 'a') : show (x `div` 26)
419 show (UVal x) = show x
420-- show (UMax l r) = "max(" ++ show l ++ ", " ++ show r ++")"
422-- | Universe constraints
423data UConstraint = ULT UExp UExp -- ^ Strictly less than
424 | ULE UExp UExp -- ^ Less than or equal to
425 deriving Eq
427instance Show UConstraint where
428 show (ULT x y) = show x ++ " < " ++ show y
429 show (ULE x y) = show x ++ " <= " ++ show y
431type UCs = (Int, [UConstraint])
433data NameType = Bound
434 | Ref
435 | DCon Int Int -- ^ Data constructor; Ints are tag and arity
436 | TCon Int Int -- ^ Type constructor; Ints are tag and arity
437 deriving (Show, Ord)
438{-!
439deriving instance Binary NameType
440!-}
442instance Sized NameType where
443 size _ = 1
445instance Pretty NameType where
446 pretty = text . show
448instance Eq NameType where
449 Bound == Bound = True
450 Ref == Ref = True
451 DCon _ a == DCon _ b = (a == b) -- ignore tag
452 TCon _ a == TCon _ b = (a == b) -- ignore tag
453 _ == _ = False
455-- | Terms in the core language
456data TT n = P NameType n (TT n) -- ^ named references
457 | V Int -- ^ a resolved de Bruijn-indexed variable
458 | Bind n (Binder (TT n)) (TT n) -- ^ a binding
459 | App (TT n) (TT n) -- ^ function, function type, arg
460 | Constant Const -- ^ constant
461 | Proj (TT n) Int -- ^ argument projection; runtime only
462 | Erased -- ^ an erased term
463 | Impossible -- ^ special case for totality checking
464 | TType UExp -- ^ the type of types at some level
465 deriving (Ord, Functor)
466{-!
467deriving instance Binary TT
468!-}
470class TermSize a where
471 termsize :: Name -> a -> Int
473instance TermSize a => TermSize [a] where
474 termsize n [] = 0
475 termsize n (x : xs) = termsize n x + termsize n xs
477instance TermSize (TT Name) where
478 termsize n (P _ x _)
479 | x == n = 1000000 -- recursive => really big
480 | otherwise = 1
481 termsize n (V _) = 1
482 termsize n (Bind n' (Let t v) sc)
483 = let rn = if n == n' then MN 0 "noname" else n in
484 termsize rn v + termsize rn sc
485 termsize n (App f a) = termsize n f + termsize n a
486 termsize n _ = 1
488instance Sized a => Sized (TT a) where
489 size (P name n trm) = 1 + size name + size n + size trm
490 size (V v) = 1
491 size (Bind nm binder bdy) = 1 + size nm + size binder + size bdy
492 size (App l r) = 1 + size l + size r
493 size (Constant c) = size c
494 size Erased = 1
495 size (TType u) = 1 + size u
497instance Pretty a => Pretty (TT a) where
498 pretty _ = text "test"
500type EnvTT n = [(n, Binder (TT n))]
502data Datatype n = Data { d_typename :: n,
503 d_typetag :: Int,
504 d_type :: (TT n),
505 d_cons :: [(n, TT n)] }
506 deriving (Show, Functor, Eq)
508instance Eq n => Eq (TT n) where
509 (==) (P xt x _) (P yt y _) = x == y
510 (==) (V x) (V y) = x == y
511 (==) (Bind _ xb xs) (Bind _ yb ys) = xb == yb && xs == ys
512 (==) (App fx ax) (App fy ay) = fx == fy && ax == ay
513 (==) (TType _) (TType _) = True -- deal with constraints later
514 (==) (Constant x) (Constant y) = x == y
515 (==) (Proj x i) (Proj y j) = x == y && i == j
516 (==) Erased _ = True
517 (==) _ Erased = True
518 (==) _ _ = False
520-- * A few handy operations on well typed terms:
522-- | A term is injective iff it is a data constructor, type constructor,
523-- constant, the type Type, pi-binding, or an application of an injective
524-- term.
525isInjective :: TT n -> Bool
526isInjective (P (DCon _ _) _ _) = True
527isInjective (P (TCon _ _) _ _) = True
528isInjective (Constant _) = True
529isInjective (TType x) = True
530isInjective (Bind _ (Pi _) sc) = True
531isInjective (App f a) = isInjective f
532isInjective _ = False
534-- | Count the number of instances of a de Bruijn index in a term
535vinstances :: Int -> TT n -> Int
536vinstances i (V x) | i == x = 1
537vinstances i (App f a) = vinstances i f + vinstances i a
538vinstances i (Bind x b sc) = instancesB b + vinstances (i + 1) sc
539 where instancesB (Let t v) = vinstances i v
540 instancesB _ = 0
541vinstances i t = 0
543instantiate :: TT n -> TT n -> TT n
544instantiate e = subst 0 where
545 subst i (V x) | i == x = e
546 subst i (Bind x b sc) = Bind x (fmap (subst i) b) (subst (i+1) sc)
547 subst i (App f a) = App (subst i f) (subst i a)
548 subst i (Proj x idx) = Proj (subst i x) idx
549 subst i t = t
551explicitNames :: TT n -> TT n
552explicitNames (Bind x b sc) = let b' = fmap explicitNames b in
553 Bind x b'
554 (explicitNames (instantiate
555 (P Bound x (binderTy b')) sc))
556explicitNames (App f a) = App (explicitNames f) (explicitNames a)
557explicitNames (Proj x idx) = Proj (explicitNames x) idx
558explicitNames t = t
560pToV :: Eq n => n -> TT n -> TT n
561pToV n = pToV' n 0
562pToV' n i (P _ x _) | n == x = V i
563pToV' n i (Bind x b sc)
564-- We can assume the inner scope has been pToVed already, so continue to
565-- resolve names from the *outer* scope which may happen to have the same id.
566-- | n == x = Bind x (fmap (pToV' n i) b) sc
567 | otherwise = Bind x (fmap (pToV' n i) b) (pToV' n (i+1) sc)
568pToV' n i (App f a) = App (pToV' n i f) (pToV' n i a)
569pToV' n i (Proj t idx) = Proj (pToV' n i t) idx
570pToV' n i t = t
572-- | Convert several names. First in the list comes out as V 0
573pToVs :: Eq n => [n] -> TT n -> TT n
574pToVs ns tm = pToVs' ns tm 0 where
575 pToVs' [] tm i = tm
576 pToVs' (n:ns) tm i = pToV' n i (pToVs' ns tm (i+1))
578vToP :: TT n -> TT n
579vToP = vToP' [] where
580 vToP' env (V i) = let (n, b) = (env !! i) in
581 P Bound n (binderTy b)
582 vToP' env (Bind n b sc) = let b' = fmap (vToP' env) b in
583 Bind n b' (vToP' ((n, b'):env) sc)
584 vToP' env (App f a) = App (vToP' env f) (vToP' env a)
585 vToP' env t = t
587finalise :: Eq n => TT n -> TT n
588finalise (Bind x b sc) = Bind x (fmap finalise b) (pToV x (finalise sc))
589finalise (App f a) = App (finalise f) (finalise a)
590finalise t = t
592subst :: Eq n => n -> TT n -> TT n -> TT n
593subst n v tm = instantiate v (pToV n tm)
595substNames :: Eq n => [(n, TT n)] -> TT n -> TT n
596substNames [] t = t
597substNames ((n, tm) : xs) t = subst n tm (substNames xs t)
599substTerm :: Eq n => TT n -> TT n -> TT n -> TT n
600substTerm old new = st where
601 st t | t == old = new
602 st (App f a) = App (st f) (st a)
603 st (Bind x b sc) = Bind x (fmap st b) (st sc)
604 st t = t
606-- Returns true if V 0 and bound name n do not occur in the term
608noOccurrence :: Eq n => n -> TT n -> Bool
609noOccurrence n t = no' 0 t
610 where
611 no' i (V x) = not (i == x)
612 no' i (P Bound x _) = not (n == x)
613 no' i (Bind n b sc) = noB' i b && no' (i+1) sc
614 where noB' i (Let t v) = no' i t && no' i v
615 noB' i (Guess t v) = no' i t && no' i v
616 noB' i b = no' i (binderTy b)
617 no' i (App f a) = no' i f && no' i a
618 no' i (Proj x _) = no' i x
619 no' i _ = True
621-- | Returns all names used free in the term
622freeNames :: Eq n => TT n -> [n]
623freeNames (P _ n _) = [n]
624freeNames (Bind n (Let t v) sc) = nub $ freeNames v ++ (freeNames sc \\ [n])
625 ++ freeNames t
626freeNames (Bind n b sc) = nub $ freeNames (binderTy b) ++ (freeNames sc \\ [n])
627freeNames (App f a) = nub $ freeNames f ++ freeNames a
628freeNames (Proj x i) = nub $ freeNames x
629freeNames _ = []
631-- | Return the arity of a (normalised) type
632arity :: TT n -> Int
633arity (Bind n (Pi t) sc) = 1 + arity sc
634arity _ = 0
636-- | Deconstruct an application; returns the function and a list of arguments
637unApply :: TT n -> (TT n, [TT n])
638unApply t = ua [] t where
639 ua args (App f a) = ua (a:args) f
640 ua args t = (t, args)
642mkApp :: TT n -> [TT n] -> TT n
643mkApp f [] = f
644mkApp f (a:as) = mkApp (App f a) as
646forget :: TT Name -> Raw
647forget tm = fe [] tm
648 where
649 fe env (P _ n _) = Var n
650 fe env (V i) = Var (env !! i)
651 fe env (Bind n b sc) = RBind n (fmap (fe env) b)
652 (fe (n:env) sc)
653 fe env (App f a) = RApp (fe env f) (fe env a)
654 fe env (Constant c)
655 = RConstant c
656 fe env (TType i) = RType
657 fe env Erased = RConstant Forgot
659bindAll :: [(n, Binder (TT n))] -> TT n -> TT n
660bindAll [] t =t
661bindAll ((n, b) : bs) t = Bind n b (bindAll bs t)
663bindTyArgs :: (TT n -> Binder (TT n)) -> [(n, TT n)] -> TT n -> TT n
664bindTyArgs b xs = bindAll (map (\ (n, ty) -> (n, b ty)) xs)
666getArgTys :: TT n -> [(n, TT n)]
667getArgTys (Bind n (Pi t) sc) = (n, t) : getArgTys sc
668getArgTys _ = []
670getRetTy :: TT n -> TT n
671getRetTy (Bind n (PVar _) sc) = getRetTy sc
672getRetTy (Bind n (PVTy _) sc) = getRetTy sc
673getRetTy (Bind n (Pi _) sc) = getRetTy sc
674getRetTy sc = sc
676uniqueName :: Name -> [Name] -> Name
677uniqueName n hs | n `elem` hs = uniqueName (nextName n) hs
678 | otherwise = n
680uniqueBinders :: [Name] -> TT Name -> TT Name
681uniqueBinders ns (Bind n b sc)
682 = let n' = uniqueName n ns in
683 Bind n' (fmap (uniqueBinders (n':ns)) b) (uniqueBinders ns sc)
684uniqueBinders ns (App f a) = App (uniqueBinders ns f) (uniqueBinders ns a)
685uniqueBinders ns t = t
688nextName (NS x s) = NS (nextName x) s
689nextName (MN i n) = MN (i+1) n
690nextName (UN x) = let (num', nm') = span isDigit (reverse x)
691 nm = reverse nm'
692 num = readN (reverse num') in
693 UN (nm ++ show (num+1))
694 where
695 readN "" = 0
696 readN x = read x
698type Term = TT Name
699type Type = Term
701type Env = EnvTT Name
703-- an environment with de Bruijn indices 'normalised' so that they all refer to
704-- this environment
706newtype WkEnvTT n = Wk (EnvTT n)
707type WkEnv = WkEnvTT Name
709instance (Eq n, Show n) => Show (TT n) where
710 show t = showEnv [] t
712instance Show Const where
713 show (I i) = show i
714 show (BI i) = show i ++ "L"
715 show (Fl f) = show f
716 show (Ch c) = show c
717 show (Str s) = show s
718 show (B8 x) = show x
719 show (B16 x) = show x
720 show (B32 x) = show x
721 show (B64 x) = show x
722 show IType = "Int"
723 show BIType = "Integer"
724 show FlType = "Float"
725 show ChType = "Char"
726 show StrType = "String"
727 show PtrType = "Ptr"
728 show B8Type = "Bits8"
729 show B16Type = "Bits16"
730 show B32Type = "Bits32"
731 show B64Type = "Bits64"
732 show VoidType = "Void"
734showEnv env t = showEnv' env t False
735showEnvDbg env t = showEnv' env t True
737prettyEnv env t = prettyEnv' env t False
738 where
739 prettyEnv' env t dbg = prettySe 10 env t dbg
741 bracket outer inner p
742 | inner > outer = lparen <> p <> rparen
743 | otherwise = p
745 prettySe p env (P nt n t) debug =
746 pretty n <+>
747 if debug then
748 lbrack <+> pretty nt <+> colon <+> prettySe 10 env t debug <+> rbrack
749 else
750 empty
751 prettySe p env (V i) debug
752 | i < length env =
753 if debug then
754 text . show . fst $ env!!i
755 else
756 lbrack <+> text (show i) <+> rbrack
757 | otherwise = text "unbound" <+> text (show i) <+> text "!"
758 prettySe p env (Bind n b@(Pi t) sc) debug
759 | noOccurrence n sc && not debug =
760 bracket p 2 $ prettySb env n b debug <> prettySe 10 ((n, b):env) sc debug
761 prettySe p env (Bind n b sc) debug =
762 bracket p 2 $ prettySb env n b debug <> prettySe 10 ((n, b):env) sc debug
763 prettySe p env (App f a) debug =
764 bracket p 1 $ prettySe 1 env f debug <+> prettySe 0 env a debug
765 prettySe p env (Proj x i) debug =
766 prettySe 1 env x debug <+> text ("!" ++ show i)
767 prettySe p env (Constant c) debug = pretty c
768 prettySe p env Erased debug = text "[_]"
769 prettySe p env (TType i) debug = text "Type" <+> (text . show $ i)
771 prettySb env n (Lam t) = prettyB env "λ" "=>" n t
772 prettySb env n (Hole t) = prettyB env "?defer" "." n t
773 prettySb env n (Pi t) = prettyB env "(" ") ->" n t
774 prettySb env n (PVar t) = prettyB env "pat" "." n t
775 prettySb env n (PVTy t) = prettyB env "pty" "." n t
776 prettySb env n (Let t v) = prettyBv env "let" "in" n t v
777 prettySb env n (Guess t v) = prettyBv env "??" "in" n t v
779 prettyB env op sc n t debug =
780 text op <> pretty n <+> colon <+> prettySe 10 env t debug <> text sc
782 prettyBv env op sc n t v debug =
783 text op <> pretty n <+> colon <+> prettySe 10 env t debug <+> text "=" <+>
784 prettySe 10 env v debug <> text sc
787showEnv' env t dbg = se 10 env t where
788 se p env (P nt n t) = show n
789 ++ if dbg then "{" ++ show nt ++ " : " ++ se 10 env t ++ "}" else ""
790 se p env (V i) | i < length env = (show $ fst $ env!!i) ++
791 if dbg then "{" ++ show i ++ "}" else ""
792 | otherwise = "!!V " ++ show i ++ "!!"
793 se p env (Bind n b@(Pi t) sc)
794 | noOccurrence n sc && not dbg = bracket p 2 $ se 1 env t ++ " -> " ++ se 10 ((n,b):env) sc
795 se p env (Bind n b sc) = bracket p 2 $ sb env n b ++ se 10 ((n,b):env) sc
796 se p env (App f a) = bracket p 1 $ se 1 env f ++ " " ++ se 0 env a
797 se p env (Proj x i) = se 1 env x ++ "!" ++ show i
798 se p env (Constant c) = show c
799 se p env Erased = "[__]"
800 se p env Impossible = "[impossible]"
801 se p env (TType i) = "Type " ++ show i
803 sb env n (Lam t) = showb env "\\ " " => " n t
804 sb env n (Hole t) = showb env "? " ". " n t
805 sb env n (GHole t) = showb env "?defer " ". " n t
806 sb env n (Pi t) = showb env "(" ") -> " n t
807 sb env n (PVar t) = showb env "pat " ". " n t
808 sb env n (PVTy t) = showb env "pty " ". " n t
809 sb env n (Let t v) = showbv env "let " " in " n t v
810 sb env n (Guess t v) = showbv env "?? " " in " n t v
812 showb env op sc n t = op ++ show n ++ " : " ++ se 10 env t ++ sc
813 showbv env op sc n t v = op ++ show n ++ " : " ++ se 10 env t ++ " = " ++
814 se 10 env v ++ sc
816 bracket outer inner str | inner > outer = "(" ++ str ++ ")"
817 | otherwise = str
819-- | Check whether a term has any holes in it - impure if so
820pureTerm :: TT Name -> Bool
821pureTerm (App f a) = pureTerm f && pureTerm a
822pureTerm (Bind n b sc) = notClassName n && pureBinder b && pureTerm sc where
823 pureBinder (Hole _) = False
824 pureBinder (Guess _ _) = False
825 pureBinder (Let t v) = pureTerm t && pureTerm v
826 pureBinder t = pureTerm (binderTy t)
828 notClassName (MN _ "class") = False
829 notClassName _ = True
831pureTerm _ = True
833-- | Weaken a term by adding i to each de Bruijn index (i.e. lift it over i bindings)
834weakenTm :: Int -> TT n -> TT n
835weakenTm i t = wk i 0 t
836 where wk i min (V x) | x >= min = V (i + x)
837 wk i m (App f a) = App (wk i m f) (wk i m a)
838 wk i m (Bind x b sc) = Bind x (wkb i m b) (wk i (m + 1) sc)
839 wk i m t = t
840 wkb i m t = fmap (wk i m) t
842-- | Weaken an environment so that all the de Bruijn indices are correct according
843-- to the latest bound variable
845weakenEnv :: EnvTT n -> EnvTT n
846weakenEnv env = wk (length env - 1) env
847 where wk i [] = []
848 wk i ((n, b) : bs) = (n, weakenTmB i b) : wk (i - 1) bs
849 weakenTmB i (Let t v) = Let (weakenTm i t) (weakenTm i v)
850 weakenTmB i (Guess t v) = Guess (weakenTm i t) (weakenTm i v)
851 weakenTmB i t = t { binderTy = weakenTm i (binderTy t) }
853weakenTmEnv :: Int -> EnvTT n -> EnvTT n
854weakenTmEnv i = map (\ (n, b) -> (n, fmap (weakenTm i) b))
856orderPats :: Term -> Term
857orderPats tm = op [] tm
858 where
859 op ps (Bind n (PVar t) sc) = op ((n, PVar t) : ps) sc
860 op ps (Bind n (Hole t) sc) = op ((n, Hole t) : ps) sc
861 op ps sc = bindAll (map (\ (n, t) -> (n, t)) (sortP ps)) sc
863 sortP ps = pick [] (reverse ps)
865 namesIn (P _ n _) = [n]
866 namesIn (Bind n b t) = nub $ nb b ++ (namesIn t \\ [n])
867 where nb (Let t v) = nub (namesIn t) ++ nub (namesIn v)
868 nb (Guess t v) = nub (namesIn t) ++ nub (namesIn v)
869 nb t = namesIn (binderTy t)
870 namesIn (App f a) = nub (namesIn f ++ namesIn a)
871 namesIn _ = []
873 pick acc [] = reverse acc
874 pick acc ((n, t) : ps) = pick (insert n t acc) ps
876 insert n t [] = [(n, t)]
877 insert n t ((n',t') : ps)
878 | n `elem` (namesIn (binderTy t') ++
879 concatMap namesIn (map (binderTy . snd) ps))
880 = (n', t') : insert n t ps
881 | otherwise = (n,t):(n',t'):ps