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ContainsText

Function ContainsText( const AText, ASubText : string) : Boolean

Example​

procedure ScriptEvent(var Value: variant);
begin
  Value := ContainsText('Velox integration', 'INTEGRATION');
end;

Usage​

ContainsText reports whether text contains a substring using Velox's case-insensitive text comparison.

Parameters

NameTypeDescription
ATextstring, constComplete text to search.
ASubTextstring, constSubstring to find. Parameter order is text first, substring second.

Returns

True when the case-insensitive transformed substring occurs at a one-based position in the transformed text; otherwise False.

Behaviour

ASCII case variants normally match. The match can start at any character. The function returns only presence, not the match position or count.

An empty substring returns False in the current path because Velox's AnsiPos('', AText) returns zero. This differs from many mathematical definitions of an empty substring and from EndsText, where an empty suffix returns True.

Errors

There is no normal content-dependent exception. Large allocations can fail under general memory pressure.

Usage notes

Use this routine for human-facing case-insensitive containment when the deployed Velox/Windows case rules are acceptable. For technical identifiers or protocol fields, define the required normalisation and comparison explicitly.

Additional Technical Info​

ContainsText reports whether ASubText occurs anywhere within AText using Delphi's case-insensitive System.StrUtils routine. Velox binds directly to the RTL implementation.

The example returns True. It is source-reviewed and is not executed by the documentation workflow.

Implementation

The PascalScript import points directly to System.StrUtils.ContainsText, which calls AnsiContainsText. Current Delphi source uppercases both strings with AnsiUpperCase, searches with AnsiPos, and tests whether the returned position is greater than zero.

This implementation can allocate uppercase copies of both inputs. Its case mapping can use Windows/user-locale behaviour; the subsequent substring search is ordinal over the transformed strings.

Edge cases and quirks

  • Parameter order is AText, ASubText; reversing them changes the search.
  • Case behaviour is not the ordinal ASCII-only implementation used by CompareText. Locale-specific mappings can affect results.
  • Unicode case mappings that expand, contract or have context-sensitive forms can produce results that differ from full Unicode case-folding expectations.
  • The function does not normalise Unicode. Visually equivalent precomposed and decomposed strings may not match.
  • Empty text with a nonempty substring returns False; an empty substring also returns False, including when both arguments are empty.
  • The routine is a substring test, not token, word, path or identifier matching. For example, searching for cat can match inside concatenate.

Side effects

None. The supplied strings are not modified; temporary transformed strings are local to the call.

Performance and concurrency

Uppercasing is proportional to both input lengths and creates temporary strings. Substring-search cost depends on the transformed lengths and match position. The function has no private shared state, but case mapping can depend on process/user locale state.

Related entries

  • CompareText performs ordinal case-insensitive ordering.
  • EndsText tests a suffix and has different empty-input behaviour.
  • Comparison compares the group's text semantics.

External references

Created 2026-07-15