git.iko.soy/elk
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elk/elm/src/Optimize.hs
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1module Optimize (optimize) where
3import Ast
4import Control.Arrow (second)
5import Data.Char (isAlpha)
8optimize exp = if exp == exp' then exp' else optimize exp'
9 where exp' = simp exp
11simp expr =
12 let f = simp in
13 case expr of
14 Range e1 e2 -> Range (f e1) (f e2)
15 Binop op e1 e2 -> simp_binop op (f e1) (f e2)
16 Lambda x e -> Lambda x (f e)
17 App e1 e2 -> App (f e1) (f e2)
18 If e1 e2 e3 -> simp_if (f e1) (f e2) (f e3)
19 Let defs e -> Let (map (second f) defs) (f e)
20 Data name es -> Data name (map f es)
21 Case e cases -> Case (f e) (map (second f) cases)
22 _ -> expr
24simp_if (Boolean b) e2 e3 = if b then e2 else e3
25simp_if a b c = If a b c
27simp_binop "mod" (Number n) (Number m) = Number (mod n m)
28simp_binop "mod" e1 e2 = Binop "mod" e1 e2
29simp_binop str e1 e2
30 | isAlpha (head str) || '_' == head str = App (App (Var str) e1) e2
31 | otherwise = binop str e1 e2
33binop op (Number n) (Number m) = f n m
34 where f a b = case op of
35 { "+" -> Number $ (+) a b
36 ; "-" -> Number $ (-) a b
37 ; "*" -> Number $ (*) a b
38 --; "/" -> Number $ div a b
39 ; "<" -> Boolean $ a < b
40 ; ">" -> Boolean $ a < b
41 ; "<=" -> Boolean $ a <= b
42 ; ">=" -> Boolean $ a >= b
43 ; "==" -> Boolean $ a == b
44 ; "/=" -> Boolean $ a /= b
45 ; _ -> Binop op (Number n) (Number m) }
47binop "-" e (Number 0) = e
48binop "+" (Number 0) e = e
49binop "+" (Number n) (Binop "+" (Number m) e) = binop "+" (Number (n+m)) e
50binop "+" (Number n) (Binop "+" e (Number m)) = binop "+" (Number (n+m)) e
52binop "/" e (Number 1) = e
53binop "*" (Number 0) e = Number 0
54binop "*" (Number 1) e = e
55binop "*" (Number n) (Binop "*" (Number m) e) = binop "*" (Number (n*m)) e
56binop "*" (Number n) (Binop "*" e (Number m)) = binop "*" (Number (n*m)) e
58binop "+" e (Number n) = binop "+" (Number n) e
59binop "*" e (Number n) = binop "*" (Number n) e
61binop op (Boolean n) (Boolean m) = f n m
62 where f a b = case op of { "&&" -> Boolean $ (&&) n m
63 ; "||" -> Boolean $ (||) n m
64 ; _ -> Binop op (Boolean n) (Boolean m) }
66binop "&&" (Boolean True) e = e
67binop "&&" (Boolean False) e = Boolean False
68binop "||" (Boolean True) e = Boolean True
69binop "||" (Boolean False) e = e
71binop op e (Boolean n) = binop op (Boolean n) e
73binop ":" h t = cons h t
74binop "++" (Str s1) (Str s2) = Str $ s1 ++ s2
75binop "++" (Str s1) (Binop "++" (Str s2) e) = Binop "++" (Str $ s1 ++ s2) e
76binop "++" (Binop "++" e (Str s1)) (Str s2) = Binop "++" e (Str $ s1 ++ s2)
77binop "++" (Data "Nil" []) e = e
78binop "++" e (Data "Nil" []) = e
79binop "++" (Data "Cons" [h,t]) e = Data "Cons" [h, binop "++" t e]
81binop "$" e1 e2 = App e1 e2
83binop op e1 e2 = Binop op e1 e2
84--}