view lib/ur/option.urs @ 1394:d328983dc5a6

Allow subqueries to reference aggregate-only columns of free tables; treat non-COUNT aggregate functions as possibly returning NULL
author Adam Chlipala <adam@chlipala.net>
date Sat, 15 Jan 2011 14:53:13 -0500
parents 757dbac0454d
children a99b743a3087
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datatype t = datatype Basis.option

val eq : a ::: Type -> eq a -> eq (t a)
val ord : a ::: Type -> ord a -> ord (t a)

val isNone : a ::: Type -> t a -> bool
val isSome : a ::: Type -> t a -> bool

val mp : a ::: Type -> b ::: Type -> (a -> b) -> t a -> t b
val bind : a ::: Type -> b ::: Type -> (a -> option b) -> t a -> t b

val get : a ::: Type -> a -> option a -> a