100 lines
2.1 KiB
ObjectPascal
100 lines
2.1 KiB
ObjectPascal
type
|
|
Ordering = (_EQ, _LT, _GT);
|
|
|
|
Eq<T> = abstract class
|
|
public
|
|
|
|
function equal(x, y: T): boolean; virtual;
|
|
begin
|
|
Result := not notEqual(x, y);
|
|
end;
|
|
|
|
function notEqual(x, y: T) :boolean; virtual;
|
|
begin
|
|
Result := not equal(x, y);
|
|
end;
|
|
end;
|
|
|
|
Ord<T, EqT> = abstract class
|
|
where EqT: Eq<T>;
|
|
public
|
|
|
|
|
|
function compare(x, y: T): Ordering; virtual;
|
|
begin
|
|
var eqInst := __ConceptSingleton&<EqT>.&Instance;
|
|
if eqInst.equal(x, y) then
|
|
Result := _EQ
|
|
else if less(x, y) then
|
|
Result := _LT
|
|
else
|
|
Result := _GT;
|
|
end;
|
|
function less(x, y: T): boolean; virtual;
|
|
begin
|
|
Result := compare(x, y) = _LT;
|
|
end;
|
|
function lessEqual(x, y: T): boolean; virtual;
|
|
begin
|
|
Result := compare(x, y) <> _GT;
|
|
end;
|
|
function greater(x, y: T): boolean; virtual;
|
|
begin
|
|
Result := compare(x, y) = _GT;
|
|
end;
|
|
function greaterEqual(x, y: T): boolean; virtual;
|
|
begin
|
|
Result := compare(x, y) <> _LT;
|
|
end;
|
|
function min(x, y: T): T; virtual;
|
|
begin
|
|
Result := lessEqual(x, y) ? x : y;
|
|
end;
|
|
function max(x, y: T): T; virtual;
|
|
begin
|
|
Result := lessEqual(x, y) ? y : x;
|
|
end;
|
|
end;
|
|
|
|
|
|
Eq_integer = class(Eq<integer>)
|
|
public
|
|
|
|
function equal(x, y: integer): boolean; override;
|
|
begin
|
|
Result := x = y;
|
|
end;
|
|
end;
|
|
|
|
|
|
Ord_integer<EqT> = class(Ord<integer, EqT>)
|
|
where EqT: Eq<integer>, constructor;
|
|
public
|
|
|
|
function compare(x, y:integer): Ordering; override;
|
|
begin
|
|
var eqInst := __ConceptSingleton&<EqT>.&Instance;
|
|
if eqInst.equal(x, y) then
|
|
Result := _EQ
|
|
else if x < y then
|
|
Result := _LT
|
|
else
|
|
Result := _GT;
|
|
end;
|
|
end;
|
|
|
|
|
|
function Max3<T, EqT, OrdT>(v1, v2, v3: T): T;
|
|
where EqT: Eq<T>, constructor;
|
|
where OrdT: Ord<T, EqT>, constructor;
|
|
begin
|
|
var eqInst := __ConceptSingleton&<EqT>.&Instance;
|
|
var ordInst := __ConceptSingleton&<OrdT>.&Instance;
|
|
|
|
Result := ordInst.max(v1, ordInst.max(v2, v3));
|
|
end;
|
|
|
|
|
|
begin
|
|
writeln(Max3&<integer, Eq_integer, Ord_integer<Eq_integer>>(1, 2, 3))
|
|
end. |