Mercurial > urweb
view lib/ur/option.ur @ 930:51bc7681c47e
Nullable columns *might* be working, but too much JS is generated for the page to load in finite time
author | Adam Chlipala <adamc@hcoop.net> |
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date | Sat, 12 Sep 2009 15:08:16 -0400 |
parents | 0d30e6338c65 |
children | da3ec6014d2f |
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datatype t = datatype Basis.option fun eq [a] (_ : eq a) = mkEq (fn x y => case (x, y) of (None, None) => True | (Some x, Some y) => x = y | _ => False) 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) fun bind [a] [b] f x = case x of None => None | Some y => f y