Re: looking for data structure advice

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"Graham" == Graham Klyne writes:

Graham> I apologize... my question was unclear. It was not the Graham> standard MonadPlus class and functions that I was asking Graham> about, but the specific instance for Maybe (i.e. or_maybe). Graham> As it happens, a couple of times in the past couple of weeks, Graham> I might have used such a function if it were available in the Graham> standard libraries. I think there has been some misunderstanding here. What the other posters wrote is that it is definitely available, but under the "mplus" name. If you want the "or_maybe" name, you can define it as: or_maybe :: Maybe a -> Maybe a -> Maybe a or_maybe = mplus but you should rather use "mplus" where you would instead use "or_maybe" because not only is "mplus" standard (you have to "import Monad"), also it allows you to use something else than "Maybe" later if you need to. So, in short: the "or_maybe" you are looking for is already available, but you should spell it "mplus". Sam -- Samuel Tardieu -- sam@rfc1149.net -- http://www.rfc1149.net/sam