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bool.opa
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bool.opa
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/*
Copyright © 2011 MLstate
This file is part of OPA.
OPA is free software: you can redistribute it and/or modify it under the
terms of the GNU Affero General Public License, version 3, as published by
the Free Software Foundation.
OPA is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for
more details.
You should have received a copy of the GNU Affero General Public License
along with OPA. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* Basic functions on booleans.
*
* @category data
* @destination public
* @author David Rajchenbach-Teller, 2010 (documentation)
* @stability stable
*/
/**
* {1 About this module}
*
* {1 Where should I start?}
*
* {1 What if I need more?}
*/
/**
* {1 Types defined in this module}
*/
/**
* Order type label for bool
*/
type Bool.order = Order.default
/**
* {1 Interface}
*/
Bool =
{{
/**
* Convert a boolean to a string representation.
*
* @return ["true"] or ["false"]
*/
@stringifier(bool) to_string(b: bool) = if b then "true" else "false"
/**
* Convert a string to a boolean representation.
*/
of_string =
| "true" -> some(true)
| "false" -> some(false)
| _ -> none
/**
* Order on boolean values ([false] < [true])
*/
order = Order.make(ordering) : order(bool, Bool.order)
/**
* Comparing boolean values ([false] < [true])
*/
ordering(b1, b2) : Order.ordering =
// TODO: Do we want BSL for that? Guess not...
match (b1: bool, b2: bool) with
| ({false}, {true}) -> {lt}
| ({true}, {false}) -> {gt}
| ({false}, {false})
| ({true}, {true}) -> {eq}
}}