On 8/16/06, Casey Hawthorne <[EMAIL PROTECTED]> wrote:
The Q Programming Language can do symbolic manipulation -- Haskell?
The Q Programming Language can do the following:
sqr X = X*X
==>sqr 5
25
==>sqr (X+1)
(X+1)*(X+1)
Can Haskell do symbolic manipulation?
Or are term-rewriting and the lambda calculus sufficiently far enough
apart concepts?
You can do (if you don't mind cheating) :
Compiling Sym ( Sym.hs, interpreted )
:Ok, modules loaded: Sym.
*Sym> :!cat Sym.hs
module Sym where
data Sym a = Const a
| Var String
| Sym a `Mult` Sym a
| Sym a `Plus` Sym a
| Sym a `Minus` Sym a
deriving (Eq,Show)
instance Num a => Num (Sym a) where
(+) = Plus
(*) = Mult
abs = id
signum = id
fromInteger = Const . fromInteger
sqr x = x*x
*Sym> sqr 5
25
*Sym> sqr (Var "X" + 1)
(Var "X" Plus Const 1) Mult (Var "X" Plus Const 1)
--
Cheers,
Lemmih
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