prettyPreAcc pp alvl wrap (Index _ty acc ix)
  = wrap $ sep [pp alvl parens acc, char '!', prettyPreExp pp 0 alvl id ix]
prettyPreAcc pp alvl wrap (Index _ty acc ix)
  = wrap $ sep [pp alvl parens acc, char '!', prettyPreExp pp 0 alvl id ix]
prettyPreAcc pp alvl wrap (Index _ty acc ix)
  = wrap $ sep [pp alvl parens acc, char '!', prettyPreExp pp 0 alvl id ix]