summaryrefslogtreecommitdiff
path: root/src/compiler/GF/Compile/Compute/AppPredefined.hs
blob: 2a1998283ad04020ace0262f4328bf3820d220fc (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
----------------------------------------------------------------------
-- |
-- Module      : AppPredefined
-- Maintainer  : AR
-- Stability   : (stable)
-- Portability : (portable)
--
-- > CVS $Date: 2005/10/06 14:21:34 $ 
-- > CVS $Author: aarne $
-- > CVS $Revision: 1.13 $
--
-- Predefined function type signatures and definitions.
-----------------------------------------------------------------------------

module GF.Compile.Compute.AppPredefined ({-
          isInPredefined, typPredefined, arrityPredefined, predefModInfo, appPredefined-}
		  ) where
{-
import GF.Compile.TypeCheck.Primitives
import GF.Infra.Option
import GF.Data.Operations
import GF.Grammar
import GF.Grammar.Predef

import qualified Data.Map as Map
import Text.PrettyPrint
import Data.Char (isUpper,toUpper,toLower)

-- predefined function type signatures and definitions. AR 12/3/2003.

isInPredefined :: Ident -> Bool
isInPredefined f = Map.member f primitives

arrityPredefined :: Ident -> Maybe Int
arrityPredefined f = do ty <- typPredefined f
                        let (ctxt,_) = typeFormCnc ty
                        return (length ctxt)

predefModInfo :: SourceModInfo
predefModInfo = ModInfo MTResource MSComplete noOptions [] Nothing [] [] "Predef.gf" Nothing primitives

appPredefined :: Term -> Err (Term,Bool)
appPredefined t = case t of
  App f x0 -> do
   (x,_) <- appPredefined x0
   case f of
    -- one-place functions
    Q (mod,f) | mod == cPredef ->
      case x of
        (K s) | f == cLength  -> retb $ EInt $ length s
        (K s) | f == cIsUpper -> retb $ if (all isUpper s) then predefTrue else predefFalse
        (K s) | f == cToUpper -> retb $ K $ map toUpper s
        (K s) | f == cToLower -> retb $ K $ map toLower s
        (K s) | f == cError   -> retb $ Error s

        _                    -> retb t

    -- two-place functions
    App (Q (mod,f)) z0 | mod == cPredef -> do
     (z,_) <- appPredefined z0
     case (norm z, norm x) of
      (EInt i, K s)    | f == cDrop    -> retb $ K (drop i s)
      (EInt i, K s)    | f == cTake    -> retb $ K (take i s)
      (EInt i, K s)    | f == cTk      -> retb $ K (take (max 0 (length s - i)) s)
      (EInt i, K s)    | f == cDp      -> retb $ K (drop (max 0 (length s - i)) s)
      (K s,    K t)    | f == cEqStr   -> retb $ if s == t then predefTrue else predefFalse
      (K s,    K t)    | f == cOccur   -> retb $ if substring s t then predefTrue else predefFalse
      (K s,    K t)    | f == cOccurs  -> retb $ if any (flip elem t) s then predefTrue else predefFalse
      (EInt i, EInt j) | f == cEqInt   -> retb $ if i==j then predefTrue else predefFalse
      (EInt i, EInt j) | f == cLessInt -> retb $ if i<j  then predefTrue else predefFalse
      (EInt i, EInt j) | f == cPlus    -> retb $ EInt $ i+j
      (_,      t)      | f == cShow  && notVar t  -> retb $ foldrC $ map K $ words $ render (ppTerm Unqualified 0 t)
      (_,      K s)    | f == cRead    -> retb $ Cn (identS s) --- because of K, only works for atomic tags
      (_,      t)      | f == cToStr   -> trm2str t >>= retb
      _ -> retb t ---- prtBad "cannot compute predefined" t

    -- three-place functions
    App (App (Q (mod,f)) z0) y0 | mod == cPredef -> do
     (y,_) <- appPredefined y0
     (z,_) <- appPredefined z0
     case (z, y, x) of
       (ty,op,t) | f == cMapStr -> retf $ mapStr ty op t
       _ | f == cEqVal && notVar y && notVar x -> retb $ if y==x then predefTrue else predefFalse
       _ -> retb t ---- prtBad "cannot compute predefined" t

    _ -> retb t ---- prtBad "cannot compute predefined" t
  _ -> retb t
                  ---- should really check the absence of arg variables
 where
   retb t = return (retc t,True)  -- no further computing needed
   retf t = return (retc t,False) -- must be computed further
   retc t = case t of
     K [] -> t
     K s  -> foldr1 C (map K (words s))
     _    -> t
   norm t = case t of
     Empty -> K []
     C u v -> case (norm u,norm v) of
       (K x,K y) -> K (x +++ y)
       _ -> t
     _ -> t
   notVar t = case t of
     Vr _ -> False
     App f a -> notVar f && notVar a
     _ -> True ---- would need to check that t is a value
   foldrC ts = if null ts then Empty else foldr1 C ts

-- read makes variables into constants

predefTrue = QC (cPredef,cPTrue)
predefFalse = QC (cPredef,cPFalse)

substring :: String -> String -> Bool
substring s t = case (s,t) of
  (c:cs, d:ds) -> (c == d && substring cs ds) || substring s ds
  ([],_) -> True
  _ -> False

trm2str :: Term -> Err Term
trm2str t = case t of
  R ((_,(_,s)):_) -> trm2str s
  T _ ((_,s):_)   -> trm2str s
  V _ (s:_)       -> trm2str s
  C _ _           -> return $ t
  K _             -> return $ t
  S c _           -> trm2str c
  Empty           -> return $ t
  _               -> Bad (render (text "cannot get Str from term" <+> ppTerm Unqualified 0 t))

-- simultaneous recursion on type and term: type arg is essential!
-- But simplify the task by assuming records are type-annotated
-- (this has been done in type checking)
mapStr :: Type -> Term -> Term -> Term
mapStr ty f t = case (ty,t) of
  _ | elem ty [typeStr,typeTok] -> App f t
  (_,        R ts)    -> R [(l,mapField v)   | (l,v) <- ts]
  (Table a b,T ti cs) -> T ti [(p,mapStr b f v) | (p,v) <- cs]
  _    -> t 
 where
   mapField (mty,te) = case mty of
     Just ty -> (mty,mapStr ty f te)
     _ -> (mty,te)
-}