/
NemerleCollectionsComparer.n
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/
NemerleCollectionsComparer.n
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/*
* Copyright (c) 2009-2009 rampelstinskin@gmail.com
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of rampelstinskin may not be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
* NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
using System;
using Nemerle.Collections;
using Nemerle.Text;
using Nemerle.Utility;
namespace Nemerle.Collections
{
internal class NemerleCollectionsComparer
{
public abstract class Comparer[T]
{
private static default_ : T * T -> int = Create();
public static Default : T * T -> int
{
get
{
if (default_ == null)
{
throw ArgumentException($"Type $(typeof(T).FullName) must implement System.IComparable[$(typeof(T).FullName)].");
}
else
{
default_;
}
}
}
public abstract CreateImpl() : T * T -> int;
private static Create() : T * T -> int
{
def create(comparerType, comparableType)
{
def comparerType = comparerType.GetGenericTypeDefinition().MakeGenericType(array[comparableType]);
def creator = Activator.CreateInstance(comparerType) :> Comparer[T];
creator.CreateImpl();
}
match (typeof(T))
{
| comparableType when typeof(IComparable[T]).IsAssignableFrom(comparableType) =>
create(typeof(GenericComparer[int]), comparableType);
| _ => null;
}
}
}
private class GenericComparer[T] : Comparer[T]
where T : IComparable[T]
{
public override CreateImpl() : T * T -> int
{
_.CompareTo(_)
}
}
/*
private class NullableComparer[T] : Comparer[T?]
where T : struct
{
private _cmp : T * T -> int = NemerleCollectionsComparer.Comparer.Default;
protected override CreateImpl() : T? * T? -> int
{
fun(x, y)
{
if (x.HasValue)
{
if (y.HasValue)
{
_cmp(x.Value, y.Value);
}
else
{
1;
}
}
else
{
if (y.HasValue)
{
-1;
}
else
{
0;
}
}
}
}
}
*/
}
}