(Delphi ActiveX) Regular Expression with Multiple Matches and Named Capture Groups

See more Regular Expressions Examples

Note: This example requires Chilkat v11.1.0 or greater.

Chilkat for Delphi Downloads Chilkat ActiveX DLL for Delphi Chilkat non-ActiveX DLL for Delphi * The examples here use the ActiveX DLL.

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Chilkat_TLB;

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Integer;
sb: TChilkatStringBuilder;
crlf: Integer;
pattern: WideString;
json: TChilkatJsonObject;
timeoutMs: Integer;
numMatches: Integer;
idx_first: Integer;
idx_last: Integer;
i: Integer;
matchCount: Integer;

begin
success := 0;

sb := TChilkatStringBuilder.Create(Self);
crlf := 1;
sb.AppendLine('Name: John Smith',crlf);
sb.AppendLine('Name: Jack Johnson',crlf);
sb.AppendLine('Name: Mary Adams',crlf);

Memo1.Lines.Add(sb.GetAsString());

// We have the following string:
// Name: John Smith
// Name: Jack Johnson
// Name: Mary Adams

pattern := 'Name:\\s+(?<first>\\w+)\\s+(?<last>\\w+)';
json := TChilkatJsonObject.Create(Self);
json.EmitCompact := 0;

timeoutMs := 2000;
numMatches := sb.RegexMatch(pattern,json.ControlInterface,timeoutMs);
if (numMatches < 0) then
  begin
    // Probably an error in the regular expression.
    // Suggestion: Use AI to help create and/or diagnose regular expressions.
    Memo1.Lines.Add(sb.LastErrorText);
    Exit;
  end;

// Examine the matches:
Memo1.Lines.Add(json.Emit());

// Here is the JSON showing the matches.
// Important:  Capture group 0 always contains the entire match — that is, the portion of the input string that matches the full regular expression.

// {
//   "named": {
//     "first": 1,
//     "last": 2
//   },
//   "match": [
//     {
//       "group": [
//         {
//           "cap": "Name: John Smith",
//           "idx": 0,
//           "len": 16
//         },
//         {
//           "cap": "John",
//           "idx": 6,
//           "len": 4
//         },
//         {
//           "cap": "Smith",
//           "idx": 11,
//           "len": 5
//         }
//       ]
//     },
//     {
//       "group": [
//         {
//           "cap": "Name: Jack Johnson",
//           "idx": 18,
//           "len": 18
//         },
//         {
//           "cap": "Jack",
//           "idx": 24,
//           "len": 4
//         },
//         {
//           "cap": "Johnson",
//           "idx": 29,
//           "len": 7
//         }
//       ]
//     },
//     {
//       "group": [
//         {
//           "cap": "Name: Mary Adams",
//           "idx": 38,
//           "len": 16
//         },
//         {
//           "cap": "Mary",
//           "idx": 44,
//           "len": 4
//         },
//         {
//           "cap": "Adams",
//           "idx": 49,
//           "len": 5
//         }
//       ]
//     }
//   ]
// }

// The capture group index is obtained by looking up the name in the JSON result.
// For example:

idx_first := json.IntOf('named.first');
idx_last := json.IntOf('named.last');

i := 0;
matchCount := json.SizeOfArray('match');
while i < matchCount do
  begin
    Memo1.Lines.Add('Match ' + IntToStr(i + 1) + ':');
    json.I := i;

    json.J := idx_first;
    Memo1.Lines.Add('first: ' + json.StringOf('match[i].group[j].cap'));

    json.J := idx_last;
    Memo1.Lines.Add('first: ' + json.StringOf('match[i].group[j].cap'));

    Memo1.Lines.Add('');
    i := i + 1;
  end;

// Output is: 

// Match 1:
// first: John
// first: Smith
// 
// Match 2:
// first: Jack
// first: Johnson
// 
// Match 3:
// first: Mary
// first: Adams
end;