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view lib/ur/option.ur @ 845:6725d73c3c31

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Mark current as effectful; add List functions
author Adam Chlipala <adamc@hcoop.net>
date Tue, 09 Jun 2009 11:12:34 -0400
parents 74a1e3bdf430
children 0d30e6338c65
line wrap: on
line source
datatype t = datatype Basis.option

fun isSome [a] x =
    case x of
        None => False
      | Some _ => True

fun mp [a] [b] f x =
    case x of
        None => None
      | Some y => Some (f y)