mirror of
https://github.com/Mercury-Language/mercury.git
synced 2025-12-16 14:25:56 +00:00
fa09dd0b55
Add a function enum.det_from_int, as requested by Julien and Zoltan. library/enum.m: library/diet.m: Move det_from_int from diet to enum. tests/hard_coded/bitmap_simple.m: Remove redundant and conflicting definition.
50 lines
1.7 KiB
Mathematica
50 lines
1.7 KiB
Mathematica
%-----------------------------------------------------------------------------%
|
|
% vim: ft=mercury ts=4 sw=4 et wm=0 tw=0
|
|
%-----------------------------------------------------------------------------%
|
|
% Copyright (C) 2000, 2005-2006 The University of Melbourne.
|
|
% This file may only be copied under the terms of the GNU Library General
|
|
% Public License - see the file COPYING.LIB in the Mercury distribution.
|
|
%-----------------------------------------------------------------------------%
|
|
%
|
|
% File: enum.m.
|
|
% Author: stayl.
|
|
% Stability: medium
|
|
%
|
|
% This module provides the typeclass `enum', which describes types
|
|
% which can be converted to and from integers without loss of information.
|
|
%
|
|
%-----------------------------------------------------------------------------%
|
|
%-----------------------------------------------------------------------------%
|
|
|
|
:- module enum.
|
|
:- interface.
|
|
|
|
% For all instances the following must hold:
|
|
% all [X] (X = from_int(to_int(X)))
|
|
% all [Int] (some [Y] Int = to_int(Y) => from_int(Int) = Y)
|
|
:- typeclass enum(T) where [
|
|
func to_int(T) = int,
|
|
func from_int(int) = T is semidet
|
|
].
|
|
|
|
% `det_from_int(I)' returns the result of `from_int(I)', but throws an
|
|
% exception if `from_int' fails.
|
|
%
|
|
:- func det_from_int(int) = T <= enum(T).
|
|
|
|
%-----------------------------------------------------------------------------%
|
|
%-----------------------------------------------------------------------------%
|
|
|
|
:- implementation.
|
|
|
|
:- import_module require.
|
|
|
|
det_from_int(I) = X :-
|
|
( X0 = from_int(I) ->
|
|
X = X0
|
|
;
|
|
unexpected($module, $pred, "from_int failed")
|
|
).
|
|
|
|
%-----------------------------------------------------------------------------%
|