git.iko.soy/Idris-dev
on 4e0fe22 help sign in
Idris-dev/src/Core/TT.hs
753 lines 24 kB history raw
1{-# LANGUAGE MultiParamTypeClasses, FunctionalDependencies, DeriveFunctor #-}
3module Core.TT where
5import Control.Monad.State
6import Debug.Trace
7import qualified Data.Map as Map
8import Data.Char
9import Data.List
10import qualified Data.Binary as B
11import Data.Binary hiding (get, put)
13import Util.Pretty hiding (Str)
15{- The language has:
16 * Full dependent types
17 * A hierarchy of universes, with cumulativity: Set : Set1, Set1 : Set2, ...
18 * Pattern matching letrec binding
19 * (primitive types defined externally)
21 Some technical stuff:
22 * Typechecker is kept as simple as possible
23 - no unification, just a checker for incomplete terms.
24 * We have a simple collection of tactics which we use to elaborate source
25 programs with implicit syntax into fully explicit terms.
26-}
28data Option = SetInSet
29 | CheckConv
30 deriving Eq
32data FC = FC { fc_fname :: String,
33 fc_line :: Int }
34 deriving Eq
35{-!
36deriving instance Binary FC
37!-}
39instance Sized FC where
40 size (FC f l) = 1 + length f
42instance Show FC where
43 show (FC f l) = f ++ ":" ++ show l
45data Err = Msg String
46 | InternalMsg String
47 | CantUnify Term Term Err [(Name, Type)] Int -- Int is 'score' - how much we did unify
48 | NoSuchVariable Name
49 | NotInjective Term Term Term
50 | CantResolve Term
51 | CantResolveAlts [String]
52 | IncompleteTerm Term
53 | UniverseError
54 | ProgramLineComment
55 | Inaccessible Name
56 | At FC Err
57 deriving Eq
59instance Sized Err where
60 size (Msg msg) = length msg
61 size (InternalMsg msg) = length msg
62 size (CantUnify left right err _ score) = size left + size right + size err
63 size (NoSuchVariable name) = size name
64 size (NotInjective l c r) = size l + size c + size r
65 size (CantResolve trm) = size trm
66 size (CantResolveAlts _) = 1
67 size (IncompleteTerm trm) = size trm
68 size UniverseError = 1
69 size ProgramLineComment = 1
70 size (At fc err) = size fc + size err
71 size (Inaccessible _) = 1
73score :: Err -> Int
74score (CantUnify _ _ m _ s) = s + score m
75score (CantResolve _) = 20
76score (NoSuchVariable _) = 1000
77score _ = 0
79instance Show Err where
80 show (Msg s) = s
81 show (InternalMsg s) = "Internal error: " ++ show s
82 show (CantUnify l r e sc i) = "CantUnify " ++ show l ++ " " ++ show r ++ " "
83 ++ show e ++ " in " ++ show sc ++ " " ++ show i
84 show (Inaccessible n) = show n ++ " is not an accessible pattern variable"
85 show _ = "Error"
87instance Pretty Err where
88 pretty (Msg m) = text m
89 pretty (CantUnify l r e _ i) =
90 if size l + size r > breakingSize then
91 text "Cannot unify" <+> colon $$
92 nest nestingSize (pretty l <+> text "and" <+> pretty r) $$
93 nest nestingSize (text "where" <+> pretty e <+> text "with" <+> (text . show $ i))
94 else
95 text "Cannot unify" <+> colon <+> pretty l <+> text "and" <+> pretty r $$
96 nest nestingSize (text "where" <+> pretty e <+> text "with" <+> (text . show $ i))
97 pretty _ = text "Error"
99data TC a = OK a
100 | Error Err
101 deriving (Eq, Functor)
103instance Pretty a => Pretty (TC a) where
104 pretty (OK ok) = pretty ok
105 pretty (Error err) =
106 if size err > breakingSize then
107 text "Error" <+> colon $$ (nest nestingSize $ pretty err)
108 else
109 text "Error" <+> colon <+> pretty err
111instance Show a => Show (TC a) where
112 show (OK x) = show x
113 show (Error str) = "Error: " ++ show str
115-- at some point, this instance should also carry type checking options
116-- (e.g. Set:Set)
118instance Monad TC where
119 return = OK
120 x >>= k = case x of
121 OK v -> k v
122 Error e -> Error e
123 fail e = Error (InternalMsg e)
125tfail :: Err -> TC a
126tfail e = Error e
128trun :: FC -> TC a -> TC a
129trun fc (OK a) = OK a
130trun fc (Error e) = Error (At fc e)
132instance MonadPlus TC where
133 mzero = fail "Unknown error"
134 (OK x) `mplus` _ = OK x
135 _ `mplus` (OK y) = OK y
136 err `mplus` _ = err
138discard :: Monad m => m a -> m ()
139discard f = f >> return ()
141showSep :: String -> [String] -> String
142showSep sep [] = ""
143showSep sep [x] = x
144showSep sep (x:xs) = x ++ sep ++ showSep sep xs
146pmap f (x, y) = (f x, f y)
148traceWhen True msg a = trace msg a
149traceWhen False _ a = a
151-- RAW TERMS ----------------------------------------------------------------
153-- Names are hierarchies of strings, describing scope (so no danger of
154-- duplicate names, but need to be careful on lookup).
155-- Also MN for machine chosen names
157data Name = UN String
158 | NS Name [String] -- root, namespaces
159 | MN Int String
160 deriving (Eq, Ord)
161{-!
162deriving instance Binary Name
163!-}
165instance Sized Name where
166 size (UN n) = 1
167 size (NS n els) = 1 + length els
168 size (MN i n) = 1
170instance Pretty Name where
171 pretty (UN n) = text n
172 pretty (NS n s) = pretty n
173 pretty (MN i s) = lbrace <+> text s <+> (text . show $ i) <+> rbrace
175instance Show Name where
176 show (UN n) = n
177 show (NS n s) = showSep "." (reverse s) ++ "." ++ show n
178 show (MN i s) = "{" ++ s ++ show i ++ "}"
181-- Contexts allow us to map names to things. A root name maps to a collection
182-- of things in different namespaces with that name.
184type Ctxt a = Map.Map Name (Map.Map Name a)
185emptyContext = Map.empty
187nsroot (NS n _) = n
188nsroot n = n
190addDef :: Name -> a -> Ctxt a -> Ctxt a
191addDef n v ctxt = case Map.lookup (nsroot n) ctxt of
192 Nothing -> Map.insert (nsroot n)
193 (Map.insert n v Map.empty) ctxt
194 Just xs -> Map.insert (nsroot n)
195 (Map.insert n v xs) ctxt
197{- lookup a name in the context, given an optional namespace.
198 The name (n) may itself have a (partial) namespace given.
200 Rules for resolution:
201 - if an explicit namespace is given, return the names which match it. If none
202 match, return all names.
203 - if the name has has explicit namespace given, return the names which match it
204 and ignore the given namespace.
205 - otherwise, return all names.
207-}
209lookupCtxtName :: Maybe [String] -> Name -> Ctxt a -> [(Name, a)]
210lookupCtxtName nspace n ctxt = case Map.lookup (nsroot n) ctxt of
211 Just xs -> filterNS (Map.toList xs)
212 Nothing -> []
213 where
214 filterNS [] = []
215 filterNS ((found, v) : xs)
216 | nsmatch n found = (found, v) : filterNS xs
217 | otherwise = filterNS xs
219 nsmatch (NS n ns) (NS p ps) = ns `isPrefixOf` ps
220 nsmatch (NS _ _) _ = False
221 nsmatch looking found = True
223lookupCtxt :: Maybe [String] -> Name -> Ctxt a -> [a]
224lookupCtxt ns n ctxt = map snd (lookupCtxtName ns n ctxt)
226updateDef :: Name -> (a -> a) -> Ctxt a -> Ctxt a
227updateDef n f ctxt
228 = let ds = lookupCtxtName Nothing n ctxt in
229 foldr (\ (n, t) c -> addDef n (f t) c) ctxt ds
231toAlist :: Ctxt a -> [(Name, a)]
232toAlist ctxt = let allns = map snd (Map.toList ctxt) in
233 concat (map (Map.toList) allns)
235addAlist :: Show a => [(Name, a)] -> Ctxt a -> Ctxt a
236addAlist [] ctxt = ctxt
237addAlist ((n, tm) : ds) ctxt = addDef n tm (addAlist ds ctxt)
239data Const = I Int | BI Integer | Fl Double | Ch Char | Str String
240 | IType | BIType | FlType | ChType | StrType
241 | PtrType | VoidType | Forgot
242 deriving (Eq, Ord)
243{-!
244deriving instance Binary Const
245!-}
247instance Sized Const where
248 size _ = 1
250instance Pretty Const where
251 pretty (I i) = text . show $ i
252 pretty (BI i) = text . show $ i
253 pretty (Fl f) = text . show $ f
254 pretty (Ch c) = text . show $ c
255 pretty (Str s) = text s
256 pretty IType = text "Int"
257 pretty BIType = text "BigInt"
258 pretty FlType = text "Float"
259 pretty ChType = text "Char"
260 pretty StrType = text "String"
261 pretty PtrType = text "Ptr"
262 pretty VoidType = text "Void"
263 pretty Forgot = text "Forgot"
265data Raw = Var Name
266 | RBind Name (Binder Raw) Raw
267 | RApp Raw Raw
268 | RSet
269 | RForce Raw
270 | RConstant Const
271 deriving (Show, Eq)
273instance Sized Raw where
274 size (Var name) = 1
275 size (RBind name bind right) = 1 + size bind + size right
276 size (RApp left right) = 1 + size left + size right
277 size RSet = 1
278 size (RForce raw) = 1 + size raw
279 size (RConstant const) = size const
281instance Pretty Raw where
282 pretty = text . show
284{-!
285deriving instance Binary Raw
286!-}
288data Binder b = Lam { binderTy :: b }
289 | Pi { binderTy :: b }
290 | Let { binderTy :: b,
291 binderVal :: b }
292 | NLet { binderTy :: b,
293 binderVal :: b }
294 | Hole { binderTy :: b}
295 | GHole { binderTy :: b}
296 | Guess { binderTy :: b,
297 binderVal :: b }
298 | PVar { binderTy :: b }
299 | PVTy { binderTy :: b }
300 deriving (Show, Eq, Ord, Functor)
301{-!
302deriving instance Binary Binder
303!-}
305instance Sized a => Sized (Binder a) where
306 size (Lam ty) = 1 + size ty
307 size (Pi ty) = 1 + size ty
308 size (Let ty val) = 1 + size ty + size val
309 size (NLet ty val) = 1 + size ty + size val
310 size (Hole ty) = 1 + size ty
311 size (GHole ty) = 1 + size ty
312 size (Guess ty val) = 1 + size ty + size val
313 size (PVar ty) = 1 + size ty
314 size (PVTy ty) = 1 + size ty
316fmapMB :: Monad m => (a -> m b) -> Binder a -> m (Binder b)
317fmapMB f (Let t v) = liftM2 Let (f t) (f v)
318fmapMB f (NLet t v) = liftM2 NLet (f t) (f v)
319fmapMB f (Guess t v) = liftM2 Guess (f t) (f v)
320fmapMB f (Lam t) = liftM Lam (f t)
321fmapMB f (Pi t) = liftM Pi (f t)
322fmapMB f (Hole t) = liftM Hole (f t)
323fmapMB f (GHole t) = liftM GHole (f t)
324fmapMB f (PVar t) = liftM PVar (f t)
325fmapMB f (PVTy t) = liftM PVTy (f t)
327raw_apply :: Raw -> [Raw] -> Raw
328raw_apply f [] = f
329raw_apply f (a : as) = raw_apply (RApp f a) as
331raw_unapply :: Raw -> (Raw, [Raw])
332raw_unapply t = ua [] t where
333 ua args (RApp f a) = ua (a:args) f
334 ua args t = (t, args)
336data RawFun = RawFun { rtype :: Raw,
337 rval :: Raw
338 }
339 deriving Show
341data RawDatatype = RDatatype Name Raw [(Name, Raw)]
342 deriving Show
344data RDef = RFunction RawFun
345 | RConst Raw
346 | RData RawDatatype
347 deriving Show
349type RProgram = [(Name, RDef)]
351-- WELL TYPED TERMS ---------------------------------------------------------
353data UExp = UVar Int -- universe variable
354 | UVal Int -- explicit universe level
355 deriving (Eq, Ord)
357instance Sized UExp where
358 size _ = 1
360-- We assume that universe levels have been checked, so anything external
361-- can just have the same universe variable and we won't get any new
362-- cycles.
364instance Binary UExp where
365 put x = return ()
366 get = return (UVar (-1))
368instance Show UExp where
369 show (UVar x) | x < 26 = [toEnum (x + fromEnum 'a')]
370 | otherwise = toEnum ((x `mod` 26) + fromEnum 'a') : show (x `div` 26)
371 show (UVal x) = show x
372-- show (UMax l r) = "max(" ++ show l ++ ", " ++ show r ++")"
374data UConstraint = ULT UExp UExp
375 | ULE UExp UExp
376 deriving Eq
378instance Show UConstraint where
379 show (ULT x y) = show x ++ " < " ++ show y
380 show (ULE x y) = show x ++ " <= " ++ show y
382type UCs = (Int, [UConstraint])
384data NameType = Bound | Ref | DCon Int Int | TCon Int Int
385 deriving (Show, Ord)
386{-!
387deriving instance Binary NameType
388!-}
390instance Sized NameType where
391 size _ = 1
393instance Pretty NameType where
394 pretty = text . show
396instance Eq NameType where
397 Bound == Bound = True
398 Ref == Ref = True
399 DCon _ a == DCon _ b = (a == b) -- ignore tag
400 TCon _ a == TCon _ b = (a == b) -- ignore tag
401 _ == _ = False
403data TT n = P NameType n (TT n) -- embed type
404 | V Int
405 | Bind n (Binder (TT n)) (TT n)
406 | App (TT n) (TT n) -- function, function type, arg
407 | Constant Const
408 | Erased
409 | Set UExp
410 deriving (Ord, Functor)
411{-!
412deriving instance Binary TT
413!-}
415instance Sized a => Sized (TT a) where
416 size (P name n trm) = 1 + size name + size n + size trm
417 size (V v) = 1
418 size (Bind nm binder bdy) = 1 + size nm + size binder + size bdy
419 size (App l r) = 1 + size l + size r
420 size (Constant c) = size c
421 size Erased = 1
422 size (Set u) = 1 + size u
424instance Pretty a => Pretty (TT a) where
425 pretty _ = text "test"
427type EnvTT n = [(n, Binder (TT n))]
429data Datatype n = Data { d_typename :: n,
430 d_typetag :: Int,
431 d_type :: (TT n),
432 d_cons :: [(n, TT n)] }
433 deriving (Show, Functor, Eq)
435instance Eq n => Eq (TT n) where
436 (==) (P xt x _) (P yt y _) = xt == yt && x == y
437 (==) (V x) (V y) = x == y
438 (==) (Bind _ xb xs) (Bind _ yb ys) = xb == yb && xs == ys
439 (==) (App fx ax) (App fy ay) = fx == fy && ax == ay
440 (==) (Set _) (Set _) = True -- deal with constraints later
441 (==) (Constant x) (Constant y) = x == y
442 (==) Erased _ = True
443 (==) _ Erased = True
444 (==) _ _ = False
446-- A few handy operations on well typed terms:
448isInjective :: TT n -> Bool
449isInjective (P (DCon _ _) _ _) = True
450isInjective (P (TCon _ _) _ _) = True
451isInjective (Constant _) = True
452isInjective (Set x) = True
453isInjective (Bind _ (Pi _) sc) = True
454isInjective (App f a) = isInjective f
455isInjective _ = False
457instantiate :: TT n -> TT n -> TT n
458instantiate e = subst 0 where
459 subst i (V x) | i == x = e
460 subst i (Bind x b sc) = Bind x (fmap (subst i) b) (subst (i+1) sc)
461 subst i (App f a) = App (subst i f) (subst i a)
462 subst i t = t
464pToV :: Eq n => n -> TT n -> TT n
465pToV n = pToV' n 0
466pToV' n i (P _ x _) | n == x = V i
467pToV' n i (Bind x b sc)
468 | n == x = Bind x (fmap (pToV' n i) b) sc
469 | otherwise = Bind x (fmap (pToV' n i) b) (pToV' n (i+1) sc)
470pToV' n i (App f a) = App (pToV' n i f) (pToV' n i a)
471pToV' n i t = t
473-- Convert several names. First in the list comes out as V 0
474pToVs :: Eq n => [n] -> TT n -> TT n
475pToVs ns tm = pToVs' ns tm 0 where
476 pToVs' [] tm i = tm
477 pToVs' (n:ns) tm i = pToV' n i (pToVs' ns tm (i+1))
479vToP :: TT n -> TT n
480vToP = vToP' [] where
481 vToP' env (V i) = let (n, b) = (env !! i) in
482 P Bound n (binderTy b)
483 vToP' env (Bind n b sc) = let b' = fmap (vToP' env) b in
484 Bind n b' (vToP' ((n, b'):env) sc)
485 vToP' env (App f a) = App (vToP' env f) (vToP' env a)
486 vToP' env t = t
488finalise :: Eq n => TT n -> TT n
489finalise (Bind x b sc) = Bind x (fmap finalise b) (pToV x (finalise sc))
490finalise (App f a) = App (finalise f) (finalise a)
491finalise t = t
493subst :: Eq n => n -> TT n -> TT n -> TT n
494subst n v tm = instantiate v (pToV n tm)
496substNames :: Eq n => [(n, TT n)] -> TT n -> TT n
497substNames [] t = t
498substNames ((n, tm) : xs) t = subst n tm (substNames xs t)
500-- Returns true if V 0 and bound name n do not occur in the term
502noOccurrence :: Eq n => n -> TT n -> Bool
503noOccurrence n t = no' 0 t
504 where
505 no' i (V x) = not (i == x)
506 no' i (P Bound x _) = not (n == x)
507 no' i (Bind n b sc) = noB' i b && no' (i+1) sc
508 where noB' i (Let t v) = no' i t && no' i v
509 noB' i (Guess t v) = no' i t && no' i v
510 noB' i b = no' i (binderTy b)
511 no' i (App f a) = no' i f && no' i a
512 no' i _ = True
514-- Returns all names used free in the term
516freeNames :: Eq n => TT n -> [n]
517freeNames (P _ n _) = [n]
518freeNames (Bind n (Let t v) sc) = nub $ freeNames v ++ (freeNames sc \\ [n])
519 ++ freeNames t
520freeNames (Bind n b sc) = nub $ freeNames (binderTy b) ++ (freeNames sc \\ [n])
521freeNames (App f a) = nub $ freeNames f ++ freeNames a
522freeNames _ = []
524-- Return the arity of a (normalised) type
526arity :: TT n -> Int
527arity (Bind n (Pi t) sc) = 1 + arity sc
528arity _ = 0
530-- deconstruct an application; returns the function and a list of arguments
532unApply :: TT n -> (TT n, [TT n])
533unApply t = ua [] t where
534 ua args (App f a) = ua (a:args) f
535 ua args t = (t, args)
537mkApp :: TT n -> [TT n] -> TT n
538mkApp f [] = f
539mkApp f (a:as) = mkApp (App f a) as
541forget :: TT Name -> Raw
542forget tm = fe [] tm
543 where
544 fe env (P _ n _) = Var n
545 fe env (V i) = Var (env !! i)
546 fe env (Bind n b sc) = RBind n (fmap (fe env) b)
547 (fe (n:env) sc)
548 fe env (App f a) = RApp (fe env f) (fe env a)
549 fe env (Constant c)
550 = RConstant c
551 fe env (Set i) = RSet
552 fe env Erased = RConstant Forgot
554bindAll :: [(n, Binder (TT n))] -> TT n -> TT n
555bindAll [] t =t
556bindAll ((n, b) : bs) t = Bind n b (bindAll bs t)
558bindTyArgs :: (TT n -> Binder (TT n)) -> [(n, TT n)] -> TT n -> TT n
559bindTyArgs b xs = bindAll (map (\ (n, ty) -> (n, b ty)) xs)
561getArgTys :: TT n -> [(n, TT n)]
562getArgTys (Bind n (Pi t) sc) = (n, t) : getArgTys sc
563getArgTys _ = []
565getRetTy :: TT n -> TT n
566getRetTy (Bind n (PVar _) sc) = getRetTy sc
567getRetTy (Bind n (PVTy _) sc) = getRetTy sc
568getRetTy (Bind n (Pi _) sc) = getRetTy sc
569getRetTy sc = sc
571uniqueName :: Name -> [Name] -> Name
572uniqueName n hs | n `elem` hs = uniqueName (nextName n) hs
573 | otherwise = n
575nextName (NS x s) = NS (nextName x) s
576nextName (MN i n) = MN (i+1) n
577nextName (UN x) = let (num', nm') = span isDigit (reverse x)
578 nm = reverse nm'
579 num = readN (reverse num') in
580 UN (nm ++ show (num+1))
581 where
582 readN "" = 0
583 readN x = read x
585type Term = TT Name
586type Type = Term
588type Env = EnvTT Name
590-- an environment with de Bruijn indices 'normalised' so that they all refer to
591-- this environment
593newtype WkEnvTT n = Wk (EnvTT n)
594type WkEnv = WkEnvTT Name
596instance (Eq n, Show n) => Show (TT n) where
597 show t = showEnv [] t
599instance Show Const where
600 show (I i) = show i
601 show (BI i) = show i ++ "L"
602 show (Fl f) = show f
603 show (Ch c) = show c
604 show (Str s) = show s
605 show IType = "Int"
606 show BIType = "Integer"
607 show FlType = "Float"
608 show ChType = "Char"
609 show StrType = "String"
610 show PtrType = "Ptr"
611 show VoidType = "Void"
613showEnv env t = showEnv' env t False
614showEnvDbg env t = showEnv' env t True
616prettyEnv env t = prettyEnv' env t False
617 where
618 prettyEnv' env t dbg = prettySe 10 env t dbg
620 bracket outer inner p
621 | inner > outer = lparen <> p <> rparen
622 | otherwise = p
624 prettySe p env (P nt n t) debug =
625 pretty n <+>
626 if debug then
627 lbrack <+> pretty nt <+> colon <+> prettySe 10 env t debug <+> rbrack
628 else
629 empty
630 prettySe p env (V i) debug
631 | i < length env =
632 if debug then
633 text . show . fst $ env!!i
634 else
635 lbrack <+> text (show i) <+> rbrack
636 | otherwise = text "unbound" <+> text (show i) <+> text "!"
637 prettySe p env (Bind n b@(Pi t) sc) debug
638 | noOccurrence n sc && not debug =
639 bracket p 2 $ prettySb env n b debug <> prettySe 10 ((n, b):env) sc debug
640 prettySe p env (Bind n b sc) debug =
641 bracket p 2 $ prettySb env n b debug <> prettySe 10 ((n, b):env) sc debug
642 prettySe p env (App f a) debug =
643 bracket p 1 $ prettySe 1 env f debug <+> prettySe 0 env a debug
644 prettySe p env (Constant c) debug = pretty c
645 prettySe p env Erased debug = text "[_]"
646 prettySe p env (Set i) debug = text "Set" <+> (text . show $ i)
648 prettySb env n (Lam t) = prettyB env "λ" "=>" n t
649 prettySb env n (Hole t) = prettyB env "?defer" "." n t
650 prettySb env n (Pi t) = prettyB env "(" ") ->" n t
651 prettySb env n (PVar t) = prettyB env "pat" "." n t
652 prettySb env n (PVTy t) = prettyB env "pty" "." n t
653 prettySb env n (Let t v) = prettyBv env "let" "in" n t v
654 prettySb env n (Guess t v) = prettyBv env "??" "in" n t v
656 prettyB env op sc n t debug =
657 text op <> pretty n <+> colon <+> prettySe 10 env t debug <> text sc
659 prettyBv env op sc n t v debug =
660 text op <> pretty n <+> colon <+> prettySe 10 env t debug <+> text "=" <+>
661 prettySe 10 env v debug <> text sc
664showEnv' env t dbg = se 10 env t where
665 se p env (P nt n t) = show n
666 ++ if dbg then "{" ++ show nt ++ " : " ++ se 10 env t ++ "}" else ""
667 se p env (V i) | i < length env = (show $ fst $ env!!i) ++
668 if dbg then "{" ++ show i ++ "}" else ""
669 | otherwise = "!!V " ++ show i ++ "!!"
670 se p env (Bind n b@(Pi t) sc)
671 | noOccurrence n sc && not dbg = bracket p 2 $ se 1 env t ++ " -> " ++ se 10 ((n,b):env) sc
672 se p env (Bind n b sc) = bracket p 2 $ sb env n b ++ se 10 ((n,b):env) sc
673 se p env (App f a) = bracket p 1 $ se 1 env f ++ " " ++ se 0 env a
674 se p env (Constant c) = show c
675 se p env Erased = "[__]"
676 se p env (Set i) = "Set " ++ show i
678 sb env n (Lam t) = showb env "\\ " " => " n t
679 sb env n (Hole t) = showb env "? " ". " n t
680 sb env n (GHole t) = showb env "?defer " ". " n t
681 sb env n (Pi t) = showb env "(" ") -> " n t
682 sb env n (PVar t) = showb env "pat " ". " n t
683 sb env n (PVTy t) = showb env "pty " ". " n t
684 sb env n (Let t v) = showbv env "let " " in " n t v
685 sb env n (Guess t v) = showbv env "?? " " in " n t v
687 showb env op sc n t = op ++ show n ++ " : " ++ se 10 env t ++ sc
688 showbv env op sc n t v = op ++ show n ++ " : " ++ se 10 env t ++ " = " ++
689 se 10 env v ++ sc
691 bracket outer inner str | inner > outer = "(" ++ str ++ ")"
692 | otherwise = str
694-- Check whether a term has any holes in it - impure if so
696pureTerm :: TT n -> Bool
697pureTerm (App f a) = pureTerm f && pureTerm a
698pureTerm (Bind n b sc) = pureBinder b && pureTerm sc where
699 pureBinder (Hole _) = False
700 pureBinder (Guess _ _) = False
701 pureBinder (Let t v) = pureTerm t && pureTerm v
702 pureBinder t = pureTerm (binderTy t)
703pureTerm _ = True
705-- weaken a term by adding i to each de Bruijn index (i.e. lift it over i bindings)
707weakenTm :: Int -> TT n -> TT n
708weakenTm i t = wk i 0 t
709 where wk i min (V x) | x >= min = V (i + x)
710 wk i m (App f a) = App (wk i m f) (wk i m a)
711 wk i m (Bind x b sc) = Bind x (wkb i m b) (wk i (m + 1) sc)
712 wk i m t = t
713 wkb i m t = fmap (wk i m) t
715-- weaken an environment so that all the de Bruijn indices are correct according
716-- to the latest bound variable
718weakenEnv :: EnvTT n -> EnvTT n
719weakenEnv env = wk (length env - 1) env
720 where wk i [] = []
721 wk i ((n, b) : bs) = (n, weakenTmB i b) : wk (i - 1) bs
722 weakenTmB i (Let t v) = Let (weakenTm i t) (weakenTm i v)
723 weakenTmB i (Guess t v) = Guess (weakenTm i t) (weakenTm i v)
724 weakenTmB i t = t { binderTy = weakenTm i (binderTy t) }
726weakenTmEnv :: Int -> EnvTT n -> EnvTT n
727weakenTmEnv i = map (\ (n, b) -> (n, fmap (weakenTm i) b))
729orderPats :: Term -> Term
730orderPats tm = op [] tm
731 where
732 op ps (Bind n (PVar t) sc) = op ((n, t) : ps) sc
733 op ps sc = bindAll (map (\ (n, t) -> (n, PVar t)) (sortP ps)) sc
735 sortP ps = pick [] (reverse ps)
737 namesIn (P _ n _) = [n]
738 namesIn (Bind n b t) = nub $ nb b ++ (namesIn t \\ [n])
739 where nb (Let t v) = nub (namesIn t) ++ nub (namesIn v)
740 nb (Guess t v) = nub (namesIn t) ++ nub (namesIn v)
741 nb t = namesIn (binderTy t)
742 namesIn (App f a) = nub (namesIn f ++ namesIn a)
743 namesIn _ = []
745 pick acc [] = reverse acc
746 pick acc ((n, t) : ps) = pick (insert n t acc) ps
748 insert n t [] = [(n, t)]
749 insert n t ((n',t') : ps)
750 | n `elem` (namesIn t' ++ concatMap namesIn (map snd ps))
751 = (n', t') : insert n t ps
752 | otherwise = (n,t):(n',t'):ps