84 lines
1.8 KiB
ObjectPascal
84 lines
1.8 KiB
ObjectPascal
type
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Ordering = (_EQ, _LT, _GT);
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Eq<T> = interface
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function equal(x, y: T): boolean;
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function notEqual(x, y: T) :boolean;
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end;
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Ord<T> = interface(Eq<T>)
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function compare(x, y: T): Ordering;
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function less(x, y: T): boolean;
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function lessEqual(x, y: T): boolean;
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function greater(x, y: T): boolean;
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function greaterEqual(x, y: T): boolean;
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function min(x, y: T): T;
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function max(x, y: T): T;
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end;
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Eq_integer = class(Eq<integer>)
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public
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function equal(x, y: integer): boolean;
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begin
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Result := x = y;
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end;
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function notEqual(x, y: integer) :boolean;
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begin
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Result := x <> y;
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end;
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end;
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Ord_integer = class(Eq_integer, Ord<integer>)
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public
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function compare(x, y:integer): Ordering;
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begin
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if self.equal(x, y) then
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Result := _EQ
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else if x < y then
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Result := _LT
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else
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Result := _GT;
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end;
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function less(x, y: integer): boolean;
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begin
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Result := compare(x, y) = _LT;
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end;
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function lessEqual(x, y: integer): boolean;
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begin
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Result := compare(x, y) <> _GT;
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end;
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function greater(x, y: integer): boolean;
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begin
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Result := compare(x, y) = _GT;
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end;
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function greaterEqual(x, y: integer): boolean;
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begin
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Result := compare(x, y) <> _LT;
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end;
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function min(x, y: integer): integer;
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begin
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Result := lessEqual(x, y) ? x : y;
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end;
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function max(x, y: integer): integer;
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begin
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Result := lessEqual(x, y) ? y : x;
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end;
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end;
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function Max3<T, OrdT>(v1, v2, v3: T): T;
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where OrdT: Ord<T>, constructor;
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begin
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var ordInst := __ConceptSingleton&<OrdT>.&Instance;
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Result := ordInst.max(v1, ordInst.max(v2, v3));
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end;
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begin
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writeln(Max3&<integer, Ord_integer>(1, 2, 3))
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end. |