Since lambda is a lower-case letter, it's debatable whether we want to
steal it to mean lambda in Haskell source. However if we did, then we
would probably want to make it a "special" symbol, not just a reserved
symbol, otherwise writing \x->... (using unicode characters of course)
wouldn't work, because \x would be treated as a single identifier,
you'd need a space.
,(">>-", ITRarrowtail, bit arrowsBit)
#if __GLASGOW_HASKELL__ >= 605
- ,("λ", ITlam, bit glaExtsBit)
,("∷", ITdcolon, bit glaExtsBit)
,("⇒", ITdarrow, bit glaExtsBit)
,("∀", ITforall, bit glaExtsBit)