plicitSum alt arity expr _)
  = text "(#" <+> ppr_bars (alt - 1) <+> ppr expr <+> ppr_bars (arity - alt) <+> text "#)"
  where
    ppr_bars n = hsep (replicate n (char '|'))

ppr_expr (
ppr_expr (ExplicitSum alt arity expr _)
  = text "(#" <+> ppr_bars (alt - 1) <+> ppr expr <+> ppr_bars (arity - alt) <+> text "#)"
  where
    ppr_bars n = hsep (replicate n (char '|'))
ppr_expr (ExplicitSum alt arity expr _)
  = text "(#" <+> ppr_bars (alt - 1) <+> ppr expr <+> ppr_bars (arity - alt) <+> text "#)"
  where
    ppr_bars n = hsep (replicate n (char '|'))