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SoundexSimilar

Function SoundexSimilar( const AText, AOther : string; ALength : TSoundexLength) : Boolean

Example​

procedure ScriptEvent(var Value: variant);
begin
  Value := SoundexSimilar('Robert', 'Rupert', 4);
end;

Usage​

SoundexSimilar reports whether two strings produce exactly equal Soundex codes at the requested length.

Parameters

NameTypeDescription
ATextstring, constFirst text to encode.
AOtherstring, constSecond text to encode.
ALengthTSoundexLengthRequested code length. Velox exposes this reference as LongInt; validate it before calling.

Returns

True when Soundex(AText, ALength) = Soundex(AOther, ALength); otherwise False.

Behaviour

The function is a grouping predicate. It answers whether the codes collide, not whether the source strings are identical, valid names or the same real-world entity.

Errors

Normal bounded inputs have no expected exception. Excessive length can raise an allocation/length error; invalid lengths can produce nonstandard codes without a validation exception.

Usage notes

Use this only as one candidate-matching signal. Confirm identity with authoritative fields and business rules. Use ResemblesText only when the host-configurable procedure indirection is intended.

Additional Technical Info​

SoundexSimilar generates a Soundex code for each input at the requested length and returns exact code equality.

The example returns True because both codes are R163. It is source-reviewed and is not executed by the documentation workflow.

Implementation

Velox binds directly to System.StrUtils.SoundexSimilar. Current Delphi source calls Soundex twice and compares the managed result strings case-sensitively. Because normal generated codes are canonical uppercase/digit strings, no additional case fold is needed.

Edge cases and quirks

  • Two empty strings return True because both codes are empty. One empty and one non-empty string return False.
  • All Soundex rules are inherited: ASCII-focused scoring, retained first character, no normalisation, invalid script lengths and the length-one bug.
  • Shorter requested lengths increase collisions. Increasing length can distinguish more later consonant groups but does not make Soundex language-neutral or unique.
  • Non-Latin or punctuation-heavy values can produce weak codes and misleading True results.
  • A very large positive length can allocate large zero-padded codes twice before comparison.

Side effects

None. Two temporary result strings are allocated.

Performance and concurrency

Work is linear in both inputs up to code completion, plus comparison proportional to the generated code length. There is no shared mutable state.

Related entries

  • Soundex returns each code for inspection.
  • SoundexCompare returns the code ordering.
  • ResemblesText normally uses four-character Soundex through a configurable procedure.

External references

Created 2026-07-15