Title: How to split text into words
procedure SplitTextIntoWords(const S: string; words: TstringList);
var
startpos, endpos: Integer;
begin
Assert(Assigned(words));
words.Clear;
startpos := 1;
while startpos = Length(S) do
begin
// skip non-letters
while (startpos = Length(S)) and not IsCharAlpha(S[startpos]) do
Inc(startpos);
if startpos = Length(S) then
begin
// find next non-letter
endpos := startpos + 1;
while (endpos = Length(S)) and IsCharAlpha(S[endpos]) do
Inc(endpos);
words.Add(Copy(S, startpos, endpos - startpos));
startpos := endpos + 1;
end; { If }
end; { While }
end; { SplitTextIntoWords }
function StringMatchesMask(S, mask: string;
case_sensitive: Boolean): Boolean;
var
sIndex, maskIndex: Integer;
begin
if not case_sensitive then
begin
S := AnsiUpperCase(S);
mask := AnsiUpperCase(mask);
end; { If }
Result := True; // blatant optimism
sIndex := 1;
maskIndex := 1;
while (sIndex = Length(S)) and (maskIndex = Length(mask)) do
begin
case mask[maskIndex] of
'?':
begin
// matches any character
Inc(sIndex);
Inc(maskIndex);
end; { case '?' }
'*':
begin
// matches 0 or more characters, so need to check for
// next character in mask
Inc(maskIndex);
if maskIndex Length(mask) then
// * at end matches rest of string
Exit
else if mask[maskindex] in ['*', '?'] then
raise Exception.Create('Invalid mask');
// look for mask character in S
while (sIndex = Length(S)) and
(S[sIndex] mask[maskIndex]) do
Inc(sIndex);
if sIndex Length(S) then
begin
// character not found, no match
Result := False;
Exit;
end;
{ If }
end; { Case '*' }
else if S[sIndex] = mask[maskIndex] then
begin
Inc(sIndex);
Inc(maskIndex);
end { If }
else
begin
// no match
Result := False;
Exit;
end;
end; { Case }
end; { While }
// if we have reached the end of both S and mask we have a complete
// match, otherwise we only have a partial match
if (sIndex = Length(S)) or (maskIndex = Length(mask)) then
Result := False;
end; { stringMatchesMask }
procedure FindMatchingWords(const S, mask: string;
case_sensitive: Boolean; matches: Tstrings);
var
words: TstringList;
i: Integer;
begin
Assert(Assigned(matches));
words := TstringList.Create;
try
SplitTextIntoWords(S, words);
matches.Clear;
for i := 0 to words.Count - 1 do
begin
if stringMatchesMask(words[i], mask, case_sensitive) then
matches.Add(words[i]);
end; { For }
finally
words.Free;
end;
end;
{
The Form has one TMemo for the text to check, one TEdit for the mask,
one TCheckbox (check = case sensitive), one TListbox for the results,
one Tbutton
}
procedure TForm1.Button1Click(Sender: TObject);
begin
FindMatchingWords(memo1.Text, edit1.Text, checkbox1.Checked, listbox1.Items);
end;