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Same

Same = 0

Example​

procedure ScriptEvent(var Value: variant);
var
  Relationship: Integer;
begin
  Relationship := CompareValueEpsilon(10.0, 10.04, 0.05);

  if Relationship = Same then
    Value := 'Within tolerance';
end;

Usage​

Same identifies the zero ordering result returned when a Velox numeric comparison treats two values as equal within tolerance.

Meaning of the result

For finite values and a valid tolerance, Same means the absolute difference falls within an inclusive equality band. It means approximate equality under the chosen comparison, not bit-for-bit identity and not equality after decimal rounding.

  • CompareValue passes no epsilon, causing Velox to calculate a magnitude- and platform-dependent default.
  • CompareValueEpsilon passes the script's absolute tolerance. A difference exactly equal to a positive epsilon still returns Same.
  • Passing epsilon zero selects Velox's calculated default rather than exact numeric equality.

Additional Technical Info​

Same is the LongInt result code for the equal branch of Velox's three-way numeric comparison. In the example, the difference is inside the explicit 0.05 boundary, so CompareValueEpsilon returns zero and Value becomes Within tolerance. The example is source-reviewed and is not executed by the documentation workflow.

Registration and implementation

vxCommonNumber declares Same as zero, and the PascalScript compile-time import registers it as a LongInt constant. It has no mutable storage or runtime callback.

Velox delegates its three-way comparison functions to Delphi System.Math.CompareValue. Delphi defines TValueRelationship as -1..1 and its equal member EqualsValue as zero. Same mirrors that result under a Velox-oriented name. Active native code returns this value through CompareValue; no active branch directly references the Same identifier itself.

Edge cases and quirks

  • Same shares its numeric value with Boolean False, but it is an ordering code. if Relationship = Same is clear; if not Relationship is not a valid or maintainable substitute.
  • NaN values do not enter Delphi's equality branch. Equal same-signed infinities also subtract to NaN and are not classified as Same by the current implementation.
  • With the calculated default tolerance, opposite infinities can produce an infinite tolerance and can classify as Same. Do not use the floating comparison as a total ordering for exceptional values.
  • A negative or NaN explicit epsilon disables conventional equality, including for equal finite values. Validate a configurable epsilon before use.
  • Default tolerance can vary with Delphi platform because Extended precision differs.

Type and conversion boundaries

The imported constant is LongInt, while Delphi's native return type is the bounded TValueRelationship. Accept only the documented LessThan, Same and MoreThan values when consuming a stored or dynamic relationship result.

Side effects

None. The constant is resolved at script compile time.

Errors

Referencing Same does not raise. Invalid numeric conversion can fail before a comparison produces the result.

Performance and concurrency

Reading the constant is allocation-free and has no shared mutable state.

Related entries

External references

Created 2026-07-15