dsl_arithmetic_1_eval_test.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") ]]

> let env = Map.fromList [("x", 1), ("y", 2)]

> prn e
"(+ 1 2 (* 0 x y) (* 1 y 2) (+ 0 x))"

> eval env e
8
-- (+ 1 2 (* 0 1 2) (* 1 2 2) (+ 0 1))
-- (+ 3 4 1)
-- 8