I said 'combinators', not 'instances'.

A lot of popular parsers
combinators can be written exclusively from (<|>) and empty, but make
little sense for List and Maybe, and may not even function properly.
The 'trifecta' package includes a nice reference:

http://hackage.haskell.org/packages/archive/trifecta/0.49.1/doc/html/Text-Trifecta-Parser-Combinators.html

See 'skipSome' through 'chainr1' - I wouldn't be surprised if most of
these lead to the same infinite loop behavior for Maybe as the stock
'many' and 'some' in base.

These sorts of functions are what Alternative is for.

Okay, I see better now what you mean.  Thank you.

But then, if so much code based on Alternative makes little sense for List and Maybe, then maybe this should be a signal they we should remove their instance from Alternative?  After all, we already have the Monad typeclass which gives them essentially the same functionality.

Cheers,

Greg