arithmetic_expression_recap.hs

let e = add [ cst(1)
            , cst(2)
            , mul [cst(0), var("x"), var("y")]
            , mul [cst(1), var("y"), cst(2)]
            , add [cst(0), var("x") ]
            ]             

-- Pretty printing an expression
prn e
> "(+ 1 2 (* 0 x y) (* 1 y 2) (+ 0 x))"

-- Optimization of an expression
prn (optimize e)
> "(+ 3 (* 2 y) x)"

-- Partial evaluation of an expression
prn $ partial (Map.fromList [("y", 0)]) e
> "(+ 3 x)"

-- Getting the list of variable names in an expression
dependencies e
> fromList ["x","y"]

-- Full evaluation of an expression
eval (Map.fromList [("x", 1), ("y", 0)]) e
> 4