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ActiveTcl User Guide
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[incr\ Tcl]
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
[ itcl ]
Copyright © 1989-1994 The Regents of the University of California.
Copyright © 1994-1996 Sun Microsystems, Inc.