is(n)                             [incr Tcl]                             is(n)



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

SYNOPSIS
       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  com-
       mand.  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 com-
              mand 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] is object
              N::c is object c is object $obj is object [code c]


KEYWORDS
       class, object




itcl                                  3.3                                is(n)