summaryrefslogtreecommitdiff
path: root/app/Frontend.hs
blob: 2c92e1f6c13e84c176de93b38ef4b7a06c63575c (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
module Frontend where

import qualified Compiler as C
import Control.Monad.IO.Class
import Control.Monad.Trans.Class
import Control.Monad.Trans.State.Lazy
import Data.Foldable (traverse_)
import qualified Data.Map as M
import qualified Interpreter as I
import qualified Parser as P
import System.Console.Haskeline
import qualified Text.Megaparsec as MP
import Text.Pretty.Simple

data PrlgState =
  PrlgState
    { defs :: I.Defs
    , ops :: P.Ops
    , strtable :: I.StrTable
    }
  deriving (Show)

type PrlgEnv a = StateT PrlgState (InputT IO) a

ppr :: Show a => a -> PrlgEnv ()
ppr x =
  liftIO $
  pPrintOpt
    CheckColorTty
    defaultOutputOptionsDarkBg
      { outputOptionsCompactParens = True
      , outputOptionsIndentAmount = 2
      , outputOptionsPageWidth = 80
      }
    x

withStrTable :: (I.StrTable -> (I.StrTable, a)) -> PrlgEnv a
withStrTable f = do
  st <- gets strtable
  let (st', x) = f st
  modify (\s -> s {strtable = st'})
  return x

findStruct :: String -> Int -> PrlgEnv I.Id
findStruct str arity = do
  stri <- findAtom str
  return I.Id {I.str = stri, I.arity = arity}

findAtom :: String -> PrlgEnv Int
findAtom = withStrTable . flip I.strtablize

interpret :: String -> PrlgEnv Bool
interpret = (>> return True) . lex
  where
    lex input = do
      case MP.parse P.lexPrlg "-" input of
        Left bundle -> liftIO $ putStr (MP.errorBundlePretty bundle)
        Right toks -> parse toks
    parse toks = do
      case MP.parse P.parsePrlg "-" toks of
        Left bundle -> liftIO $ putStr (MP.errorBundlePretty bundle)
        Right asts -> traverse_ prologize asts
    prologize ast = do
      o <- gets ops
      case P.ast2prlg o ast of
        Left err -> liftIO $ putStrLn $ "expression parsing: " ++ err
        Right prlg -> intern prlg
    intern prlgs = do
      prlgi <-
        withStrTable $ \st -> C.strtablizePrlg (C.varnames prlgs) st prlgs
      compile prlgi
    compile prlgi
      {- TODO: switch between prove goal/compile clause here -}
     = do
      commaId <- findStruct "," 2
      let code = C.seqGoals $ C.compileGoals commaId prlgi
      execute code
    execute code = do
      ds <- gets defs
      let (_, res) = I.prove code ds
      case res of
        Left err -> liftIO $ putStrLn err
        Right res ->
          liftIO $
          putStrLn $
          if res
            then "yes."
            else "no proof."

addBuiltins = do
  a1 <- findStruct "a" 1
  a <- findAtom "a"
  b <- findAtom "b"
  c <- findAtom "c"
  b0 <- findStruct "b" 0
  any <- findStruct "any" 1
  eq <- findStruct "=" 2
  modify $ \s ->
    s
      { defs =
          M.fromList
            [ (eq, [[I.U (I.LocalRef 0),I.U (I.LocalRef 0), I.NoGoal]])
            , (a1, [[I.U (I.Atom a), I.NoGoal], [I.U (I.Atom b), I.NoGoal]])
            , ( b0
              , [ [I.Goal, I.U (I.Struct a1), I.U (I.Atom c), I.LastCall]
                , [I.Goal, I.U (I.Struct a1), I.U (I.Atom b), I.LastCall]
                ])
            , (any, [[I.U I.VoidRef, I.NoGoal]])
            ]
      , ops =
        [ (",", P.Op 1000 $ P.Infix P.X P.Y)
        , ("=", P.Op 700 $ P.Infix P.X P.X)
        ]
      }

interpreterStart :: PrlgEnv ()
interpreterStart = do
  addBuiltins
  interpreterLoop

interpreterLoop :: PrlgEnv ()
interpreterLoop = do
  minput <- lift $ getInputLine "prlg> "
  case minput of
    Nothing -> return ()
    Just input -> do
      continue <- interpret input
      if continue
        then interpreterLoop
        else return ()

interpreter :: InputT IO ()
interpreter =
  evalStateT
    interpreterStart
    (PrlgState {defs = M.empty, ops = [], strtable = I.emptystrtable})