493ef51a6a
This new output form allows easy piping to the decode function of the tricu executable. Includes a new test for roundtrip evaluation of map, compilation to tree calculus terms, and decoding back to a human readable string.
164 lines
4.2 KiB
Haskell
164 lines
4.2 KiB
Haskell
module Research where
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import Control.Monad.State
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import Data.List (intercalate)
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import Data.Map (Map)
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import Data.Text (Text, replace)
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import System.Console.CmdArgs (Data, Typeable)
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import qualified Data.Map as Map
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import qualified Data.Text as T
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-- Tree Calculus Types
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data T = Leaf | Stem T | Fork T T
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deriving (Show, Eq, Ord)
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-- Abstract Syntax Tree for tricu
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data TricuAST
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= SVar String
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| SInt Int
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| SStr String
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| SList [TricuAST]
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| SFunc String [String] TricuAST
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| SApp TricuAST TricuAST
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| TLeaf
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| TStem TricuAST
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| TFork TricuAST TricuAST
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| SLambda [String] TricuAST
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| SEmpty
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deriving (Show, Eq, Ord)
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-- Tokens from Lexer
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data LToken
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= LKeywordT
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| LIdentifier String
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| LIntegerLiteral Int
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| LStringLiteral String
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| LAssign
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| LColon
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| LBackslash
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| LOpenParen
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| LCloseParen
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| LOpenBracket
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| LCloseBracket
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| LNewline
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deriving (Show, Eq, Ord)
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-- Output formats
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data CompiledForm = TreeCalculus | FSL | AST | Ternary | Ascii
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deriving (Show, Data, Typeable)
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-- Environment containing previously evaluated TC terms
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type Env = Map.Map String T
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-- Tree Calculus Reduction
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apply :: T -> T -> T
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apply Leaf b = Stem b
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apply (Stem a) b = Fork a b
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apply (Fork Leaf a) _ = a
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apply (Fork (Stem a1) a2) b = apply (apply a1 b) (apply a2 b)
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apply (Fork (Fork a1 a2) a3) Leaf = a1
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apply (Fork (Fork a1 a2) a3) (Stem u) = apply a2 u
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apply (Fork (Fork a1 a2) a3) (Fork u v) = apply (apply a3 u) v
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-- SKI Combinators
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_S :: T
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_S = Fork (Stem (Fork Leaf Leaf)) Leaf
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_K :: T
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_K = Stem Leaf
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-- Identity
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-- We use the "point-free" style which drops a redundant node
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-- Full I form (SKK): Fork (Stem (Stem Leaf)) (Stem Leaf)
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_I :: T
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_I = Fork (Stem (Stem Leaf)) Leaf
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-- Booleans
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_false :: T
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_false = Leaf
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_true :: T
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_true = Stem Leaf
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_not :: T
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_not = Fork (Fork _true (Fork Leaf _false)) Leaf
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-- Marshalling
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ofString :: String -> T
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ofString str = ofList (map ofNumber (map fromEnum str))
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ofNumber :: Int -> T
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ofNumber 0 = Leaf
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ofNumber n =
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Fork
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(if odd n then Stem Leaf else Leaf)
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(ofNumber (n `div` 2))
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ofList :: [T] -> T
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ofList [] = Leaf
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ofList (x:xs) = Fork x (ofList xs)
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toNumber :: T -> Either String Int
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toNumber Leaf = Right 0
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toNumber (Fork Leaf rest) = case toNumber rest of
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Right n -> Right (2 * n)
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Left err -> Left err
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toNumber (Fork (Stem Leaf) rest) = case toNumber rest of
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Right n -> Right (1 + 2 * n)
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Left err -> Left err
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toNumber _ = Left "Invalid Tree Calculus number"
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toString :: T -> Either String String
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toString tc = case toList tc of
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Right list -> traverse (fmap toEnum . toNumber) list
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Left err -> Left "Invalid Tree Calculus string"
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toList :: T -> Either String [T]
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toList Leaf = Right []
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toList (Fork x rest) = case toList rest of
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Right xs -> Right (x : xs)
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Left err -> Left err
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toList _ = Left "Invalid Tree Calculus list"
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-- Outputs
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formatResult :: CompiledForm -> T -> String
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formatResult TreeCalculus = toSimpleT . show
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formatResult FSL = show
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formatResult AST = show . toAST
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formatResult Ternary = toTernaryString
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formatResult Ascii = toAscii
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toSimpleT :: String -> String
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toSimpleT s = T.unpack
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$ replace "Fork" "t"
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$ replace "Stem" "t"
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$ replace "Leaf" "t"
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$ (T.pack s)
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toTernaryString :: T -> String
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toTernaryString Leaf = "0"
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toTernaryString (Stem t) = "1" ++ toTernaryString t
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toTernaryString (Fork t1 t2) = "2" ++ toTernaryString t1 ++ toTernaryString t2
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toAST :: T -> TricuAST
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toAST Leaf = TLeaf
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toAST (Stem a) = TStem (toAST a)
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toAST (Fork a b) = TFork (toAST a) (toAST b)
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toAscii :: T -> String
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toAscii tree = go tree "" True
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where
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go :: T -> String -> Bool -> String
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go Leaf prefix isLast =
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prefix ++ (if isLast then "`-- " else "|-- ") ++ "Leaf\n"
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go (Stem t) prefix isLast =
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prefix ++ (if isLast then "`-- " else "|-- ") ++ "Stem\n"
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++ go t (prefix ++ (if isLast then " " else "| ")) True
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go (Fork left right) prefix isLast =
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prefix ++ (if isLast then "`-- " else "|-- ") ++ "Fork\n"
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++ go left (prefix ++ (if isLast then " " else "| ")) False
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++ go right (prefix ++ (if isLast then " " else "| ")) True
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-- Utility
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