[NumLock]

Код:

unit Unit1;

interface

uses
  StrUtils,
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, ComCtrls;

type
  TForm1 = class(TForm)
    RichEdit1: TRichEdit;
    procedure RichEdit1Change(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.RichEdit1Change(Sender: TObject);
var
  i: Integer;
begin
  for i:=0 to RichEdit1.Lines.Count-1 do
    if (Length(RichEdit1.Lines[i])>4) and AnsiStartsStr('mes ', RichEdit1.Lines[i]) and not AnsiStartsStr('mes "', RichEdit1.Lines[i]) then ShowMessage('Пропущена открывающая кавычка')
    else if AnsiEndsStr(';', RichEdit1.Lines[i]) and not AnsiEndsStr('";', RichEdit1.Lines[i]) then ShowMessage('Пропущена закрывающая кавычка');
end;

end.