+++ /dev/null
-import "Prelude"\r
-\r
-data E = E String\r
-\r
-instance Additive E where\r
- zero = E "0"\r
- E a + E b = E ("(" + a + "+" + b + ")")\r
- \r
-instance Ring E where\r
- one = E "1"\r
- neg (E a) = E ("(-" + a + ")")\r
- E a - E b = E ("(" + a + "-" + b + ")")\r
- E a * E b = E ("(" + a + "*" + b + ")") \r
- fromInteger x = E (show x)\r
-\r
-eToString (E a) = a\r
-\r
-a = E "a"\r
-b = E "b"\r
-c = E "c"\r
-d = E "d"\r
-\r
-main = eToString (-a + b + (-c*d))\r
---\r
-(((-a)+b)+(-(c*d)))
\ No newline at end of file