prettyop f a
  | Just (V "if") <- unVar f
  , [c,x,y] <- a = 1 #> "if" <+> pretty c <+> "then" <+> pretty x <+> "else" <+> pretty y
prettyop f a
  | Just (V "if") <- unVar f
  , [c,x,y] <- a = 1 #> "if" <+> pretty c <+> "then" <+> pretty x <+> "else" <+> pretty y
prettyop f a
  | Just (V "if") <- unVar f
  , [c,x,y] <- a = 1 #> "if" <+> pretty c <+> "then" <+> pretty x <+> "else" <+> pretty y