NAME

       is - test argument to see if it is a class or an object

SYNOPSIS

       itcl::is option ?arg arg ...?

DESCRIPTION

       The  is  command is used to check if the argument given is a class or an object; depending
       on the option given. If the argument if a class or object, then 1 is returned.  Otherwise,
       0  is  returned.   The  is  command  also recognizes the commands wrapped in the itcl code
       command.

       The option argument determines what action is carried  out  by  the  command.   The  legal
       options (which may be abbreviated) are:

       is class command
              Returns 1 if command is a class, and returns 0 otherwise.

              The  fully  qualified  name of the class needs to be given as the command argument.
              So, if a class resides in a namespace, then the namespace needs to be specified  as
              well.  So, if a class C resides in a namespace N, then the command should be called
              like: is N::C
                  or is ::N::C

       is object ?-class className? command
              Returns 1 if command is an object, and returns 0 otherwise.

              If the optional "-class" parameter is specified, then the command will  be  checked
              within  the  context  of the class given. Note that className has to exist. If not,
              then an error will be given. So, if className is uncertain to be a class, then  the
              programmer  will  need  to  check  it's existance beforehand, or wrap it in a catch
              statement.

              So, if c is an  object  in  the  class  C,  in  namespace  N  then  these  are  the
              possibilities (all return 1): set obj [N::C c] itcl::is object N::c itcl::is object
              c itcl::is object $obj itcl::is object [itcl::code c]

KEYWORDS

       class, object