Find whole words within a string

Problem/Question/Abstract:

Does anyone know of a function that finds a whole word within a string as in the search and replace options?

Answer:

{Function FindWord

Parameters:
pattern: word to search for
text: text to search
caseSensitive: determines whether search is case sensitive or not. Default is not case-sensitive.
startAt: first character to search, default is 1.

Returns:
The start of the first instance of the word, or 0, if the word was not found or only as part of larger words. A word in this context is any sequence of alphanumeric characters delimited by non-alphanumeric characters.

Error Conditions: none

Created: 18.05.99 by P. Below}

function FindWord(pattern, text: string; caseSensitive: Boolean = false; startAt:
  Integer = 1): Integer;
var
  offset, endOfPattern: Integer;
begin
  Result := 0;
  if Length(text) = 0 then
    exit;
  if Length(pattern) = 0 then
  begin
    {By definition a pattern of length 0 is always found}
    result := 1;
    Exit;
  end;
  if not caseSensitive then
  begin
    pattern := AnsiLowerCase(pattern);
    text := AnsiLowerCase(text);
  end;
  endOfPattern := startAt + Length(pattern);
  for offset := startAt to Length(text) - Length(pattern) + 1 do
  begin
    if pattern[1] = text[offset] then
    begin
      if ((offset = 1) or not IsCharAlphaNumeric(text[offset - 1])) and ((endOfPattern
        > Length(text)) or  not IsCharAlphaNumeric(text[endOfPattern]))
                                and (StrLComp(@text[offset], @pattern[1], Length(pattern)) = 0) then
      begin
        Result := offset;
        exit;
      end;
    end;
    Inc(endOfPattern);
  end;
end;