'\"
'\" Copyright (c) 2007 Donal K. Fellows
'\"
'\" See the file "license.terms" for information on usage and redistribution
'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
'\"
'\" RCS: @(#) $Id: object.n,v 1.1 2008/05/31 11:42:13 dkf Exp $
'\"
.so man.macros
.TH object n 0.1 TclOO "TclOO Commands"
.BS
'\" Note:  do not modify the .SH NAME line immediately below!
.SH NAME
oo::object \- root class of the class hierarchy
.SH SYNOPSIS
.nf
package require TclOO

\fBoo::object\fI method \fR?\fIarg ...\fR?
.fi
.SH "CLASS HIERARCHY"
.nf
\fBoo::object\fR
.fi
.BE

.SH DESCRIPTION
The \fBoo::object\fR class is the root class of the object hierarchy; every
object (and hence every class) is an instance of this class. Objects are
always referred to by their name, and may be \fBrename\fRd while maintaining
their identity. Each object has a unique namespace associated with it.
Instances of objects may be made with either the \fBcreate\fR or \fBnew\fR
methods of the \fBoo::object\fR object itself, or by invoking those methods on
any of the subclass objects; see \fBoo::class\fR for more details.
.SS CONSTRUCTOR
The \fBoo::object\fR class does not define an explicit constructor.
.SS DESTRUCTOR
The \fBoo::object\fR class does not define an explicit destructor.
.SS "EXPORTED METHODS"
The \fBoo::object\fR class supports the following exported methods:
.TP
\fIobj \fBdestroy\fR
.
This method destroys the object, \fIobj\fR, that it is invoked upon, invoking
any destructors on the object's class in the process. It is equivalent to
using \fBrename\fR to delete the object command. The result of this method is
always the empty string.
.SS "NON-EXPORTED METHODS"
The \fBoo::object\fR class supports the following non-exported methods:
.TP
\fIobj \fBeval\fR ?\fIarg ...\fR?
.
This method concatenates the arguments, \fIarg\fR, as if with \fBconcat\fR,
and then evaluates the resulting script in the namespace that is uniquely
associated with \fIobj\fR, returning the result of the evaluation.
.TP
\fIobj \fBunknown \fImethodName\fR ?\fIarg ...\fR?
.
This method is called when an attempt to invoke the method \fImethodName\fR on
object \fIobj\fR fails. The arguments that the user supplied to the method are
given as \fIarg\fR argments. The default implementation (i.e. the one defined
by the \fBoo::object\fR class) generates a suitable error, detailing what
methods the object supports given whether the object was invoked by its public
name or through the \fBmy\fR command.
.TP
\fIobj \fBvariable \fIvarName \fR?\fIvarName ...\fR?
.
This method arranges for each variable called \fIvarName\fR to be linked from
the object \fIobj\fR's unique namespace into the caller's context. Thus, if it
is invoked from inside a procedure then the namespace variable in the object
is linked to the local variable in the procedure. Each \fIvarName\fR argument
must not have any namespace separators in it. The result is the empty string.
.TP
\fIobj \fBvarname \fIvarName\fR
.
This method returns the globally qualified name of the variable \fIvarName\fR
in the unique namespace for the object \fIobj\fR.
.SH EXAMPLES
This example demonstrates basic use of an object.
.CS
set obj [\fBoo::object\fR new]
$obj foo             \fI\(-> error "unknown method foo"\fR
oo::define $obj method foo {} {
    my \fBvariable\fR count
    puts "bar[incr count]"
}
$obj foo             \fI\(-> prints "bar1"\fR
$obj foo             \fI\(-> prints "bar2"\fR
$obj variable count  \fI\(-> error "unknown method variable"\fR
$obj \fBdestroy\fR
$obj foo             \fI\(-> error "unknown command obj"\fR
.CE
.SH "SEE ALSO"
my(n), oo::class(n)
.SH KEYWORDS
base class, class, object, root class

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