class TQCommand: public TList, public TQObject

 common protected method used in several constructors

 Constructor.

   Input parameters:
     1. clname - class name.
     2. obj - an object
     3. redo - method or function to do/redo operation
     4. undo - method or function to undo operation

 Comments:
    - if either clname or obj is NULL that means that redo/undo is function
    - to specify default arguments for redo/undo method/function
       '=' must precede to argument value.

  Example:
    TQCommand("TPad", gPad, "SetEditable(=kTRUE)", "SetEditable(=kFALSE)");

    - undo method can be same as redo one. In that case undo parameter
       can be omitted.

  Example:
    TQCommand("TPad", gPad, "SetFillStyle(Style_t)");

 Constructor.

   Input parameters:
     1. obj - an object
     2. redo - method or function to do/redo operation
     3. undo - method or function to undo operation

 Comments:
    - to specify default arguments for redo/undo method/function
       '=' must precede to argument value.

  Example:
    TQCommand(gPad, "SetEditable(=kTRUE)", "SetEditable(=kFALSE)");

    - undo method can be same as redo one. In that case "undo"
       can parameter be omitted.

  Example:
    TQCommand(gPad, "SetFillStyle(Style_t)");

 Copy constructor.

 dtor.

 Return a command which is doing redo/undo action.

 This static method allows to set undo parameters dynamically, i.e.
 during execution of Redo function.

 Example:
    For redo actions like TGTextEdit::DelChar() it is not possible to
    know ahead what character will be deleted.
    To set arguments for undo action ( e.g. TGTextEdit::InsChar(char)),
    one needs to call TQCommand::SetUndoArgs(1, character) from
    inside of TGTextEdit::DelChar() method, i.e.

    TQCommand::GetCommand()->SetUndoArgs(1, somechar);

 If "opt" is not zero delete every merged command which option string is
 equal to "opt". If "opt" is zero - delete all merged commands.

 Two commands can be merged if they can be composed into
 a single command (Macro command).

 To allow merging commands user might override this function.

 Add command to the list of merged commands.
 This make it possible to group complex actions together so an end user
 can undo and redo them with one command. Execution of TQUndoManager::Undo(),
 TQUndoManager::Redo() methods only invokes the top level command as a whole.

 Merge method is analogous to logical join operation.

 Note:  Merge method invokes redo action.

 Merge a collection of TQCommand.

 Add command to the list of merged commands.

 Option string can contain substrings:
  "compress" - try to compress input command
  "radd" - execute redo action of input command
  "uadd" - execute undo action of input command

 By default, commands can be compressed if they are:

  - equal
  - setter commands

 More complicated commands might want to override this function.

 Compress command. Compression is analogous to arithmetic "addition operation".

 Note:
    - The compressed command will be deleted.
    - Execution Compress method invokes Redo action with new redo arguments
      inheritied from compressed command.

 More complicated commands might want to override this function.

 Equal comparison. The commands are equal if they are
 applied to the same object and have the same Redo/Undo actions

 More complicated commands might want to override this function.

 Returns kTRUE is command if Redo is the same as Undo function
 and is the setter action.

 By default, all functions with names like "SetXXX" or "setXXX"
 considered as setters. Another type of setters are Move, Resize operations

 More complicated commands might want to override this function.

 Set do/redo and undo parameters. The format is
    SetArgs(number_of_params, redo_params, undo_params)

 Example:
     move_command->SetArgs(2, 100, 100, 200, 200);
      2 params, (100,100) - do/redo position, (200,200) - undo position

 Set redo parameters. The format is
    SetRedoArgs(number_of_params, params)

 Example:
     move_command->SetRedoArgs(2, 100, 100);

 Set undo parameters. The format is
    SetUndoArgs(number_of_params, params)

 Example:
     move_command->SetUndoArgs(2, 200, 200);

 Returns kTRUE if Redo action is possible, kFALSE if it's not.
 By default, only single sequential redo action is possible.

 Returns kTRUE if Undo action is possible, kFALSE if it's not.
 By default, only single tial undo action is possible.

 Execute command and then smerged commands

 Unexecute all merged commands and the command.
 Merged commands are executed in reverse order.

 Returns the command name. Default name is "ClassName::RedoName(args)"
 If list of merged commands is not empty the name is
 "ClassName::RedoName(args):cname1:cname2 ..."

 Returns command description.
 By default, "ClassName::RedoName(args)_ClassName::UndoName(args)"

 Returns the name of redo command

 Returns the name of undo command

 Returns a pointer to array of redo arguments

 Returns a pointer to array of undo arguments

 Returns a number of redo arguments

 Returns a number of undo arguments

 Returns an object for which undo redo acions are applied

 Returns a number of sequential undo or redo operations

 Returns kTRUE if neither redo nor undo action specified

 Undo action is in progress

 Redo action is in progress

 Returns kTRUE if command execution is in progress

 Sets name of the command

 Sets description of the command

 ls this command and merged commands

 Print collection header.