56 lines
1.1 KiB
Text
56 lines
1.1 KiB
Text
unit TrinaryLogic;
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interface
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//Define our own type for ternary logic.
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//This is actually still a Boolean, but the compiler will use distinct RTTI information.
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type
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TriBool = type Boolean;
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const
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TTrue:TriBool = True;
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TFalse:TriBool = False;
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TMaybe:TriBool = TriBool(2);
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function TVL_not(Value: TriBool): TriBool;
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function TVL_and(A, B: TriBool): TriBool;
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function TVL_or(A, B: TriBool): TriBool;
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function TVL_xor(A, B: TriBool): TriBool;
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function TVL_eq(A, B: TriBool): TriBool;
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implementation
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Uses
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SysUtils;
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function TVL_not(Value: TriBool): TriBool;
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begin
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if Value = True Then
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Result := TFalse
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else If Value = False Then
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Result := TTrue
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else
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Result := Value;
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end;
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function TVL_and(A, B: TriBool): TriBool;
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begin
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Result := TriBool(Iff(Integer(A * B) > 1, Integer(TMaybe), A * B));
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end;
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function TVL_or(A, B: TriBool): TriBool;
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begin
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Result := TVL_not(TVL_and(TVL_not(A), TVL_not(B)));
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end;
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function TVL_xor(A, B: TriBool): TriBool;
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begin
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Result := TVL_and(TVL_or(A, B), TVL_not(TVL_or(A, B)));
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end;
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function TVL_eq(A, B: TriBool): TriBool;
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begin
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Result := TVL_not(TVL_xor(A, B));
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end;
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end.
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