RemoveChars2

Function RemoveChars2( const S : string; const aCharsToRemove : TvxChars) : string

Example

procedure ScriptEvent(var Value: variant);
begin
  Value := RemoveChars2('AB-12 34', ['-', ' ']); // AB1234
end;

Usage

RemoveChars2 removes every character listed in a TvxChars set, but stops at the first embedded NUL character.

Parameters and return value

Item	Meaning
S	Source string. Empty input returns empty immediately.
aCharsToRemove	set of Char; every represented set member is filtered out.
Result	Concatenation of accepted characters before the first NUL.

Exact scan behavior

Any text after an embedded NUL is omitted from the result. Reject or normalise such input when the complete string must be processed.

Important behavior and quirks

• An embedded #0 terminates processing. The NUL and the complete suffix after it are omitted, even if those later characters are not in the removal set.
• Empty input and a string beginning with NUL both return empty.
• Membership is exact and case-sensitive.
• TvxChars is a Velox set of Char, so it represents only the set ordinal domain supported by the compiled type. It is not a Unicode category or grapheme set.
• The routine appends one character at a time. It does not modify S or the set.

Selection guidance

Use RemoveChars when the removal values are naturally supplied as a string and embedded NUL data must not silently hide the suffix. Use RemoveChars2 for a small, trusted character set and ordinary text known not to contain NUL.

Additional Technical Info

RemoveChars2 returns the source characters that are not members of aCharsToRemove. It performs a single membership scan through a NUL-terminated PChar view of the string.

The example is fictional and source-reviewed only.

Performance and concurrency

Membership testing is constant-time, but repeated result concatenation can reallocate/copy as the result grows. The function reads no shared state.

Created 2026-07-15