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is(3itcl) [incr Tcl] is(3itcl) 





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:



  

  
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





  

  
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









  

    3.3
    itcl