Joel Reymont wrote:
Support I want to infer the type given an Op that looks like this (incomplete):
data Op = Minus | Plus | Mul | LT | GT
Is there a shorthand way of bunching Minus, Plus and Mul in a function guard since they all result in TyNum whereas the rest in TyBool?
data NumOrBool = JNum | JBool deriving (Eq) numorbool Minus = JNum numorbool Plus = JNum numorbool Mul = JNum numorbool LT = JBool numorbool GT = JBool f o | numorbool o == JNum = TyNum (...) | numorbool o == JBool = TyBool (...) ...so you have to define one function rather verbosely (numorbool) but once you've done it once you can use it in a guard to define others more quickly. You could use pattern guards instead of == and forget about deriving Eq if you prefer. Jules