'\"
'\" Copyright (c) 2011-2015 Andreas Kupries
'\" Copyright (c) 2018 Donal K. Fellows
'\"
'\" See the file "license.terms" for information on usage and redistribution
'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
'\"
.TH link 3tcl 0.3 TclOO "TclOO Commands"
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'\" Note:  do not modify the .SH NAME line immediately below!
.SH NAME
link \- create link from command to method of object
.SH SYNOPSIS
.nf
package require tcl::oo

\fBlink\fR \fImethodName\fR ?\fI...\fR?
\fBlink\fR \fB{\fIcommandName methodName\fB}\fR ?\fI...\fR?
.fi
.BE
.SH DESCRIPTION
The \fBlink\fR command is available within methods. It takes a series of one
or more method names (\fImethodName ...\fR) and/or pairs of command- and
method-name (\fB{\fIcommandName methodName\fB}\fR) and makes the named methods
available as commands without requiring the explicit use of the name of the
object or the \fBmy\fR command. The method does not need to exist at the time
that the link is made; if the link command is invoked when the method does not
exist, the standard \fBunknown\fR method handling system is used.
.PP
The command name under which the method becomes available defaults to the
method name, except where explicitly specified through an alias/method pair.
Formally, every argument must be a list; if the list has two elements, the
first element is the name of the command to create and the second element is
the name of the method of the current object to which the command links;
otherwise, the name of the command and the name of the method are the same
string (the first element of the list).
.PP
If the name of the command is not a fully-qualified command name, it will be
resolved with respect to the current namespace (i.e., the object namespace).
.SH EXAMPLES
This demonstrates linking a single method in various ways. First it makes a
simple link, then a renamed link, then an external link. Note that the method
itself is unexported, but that it can still be called directly from outside
the class.
.PP
.CS
oo::class create ABC {
    method Foo {} {
        puts "This is Foo in [self]"
    }

    constructor {} {
        \fBlink\fR Foo
        # The method foo is now directly accessible as foo here
        \fBlink\fR {bar Foo}
        # The method foo is now directly accessible as bar
        \fBlink\fR {::ExternalCall Foo}
        # The method foo is now directly accessible in the global
        # namespace as ExternalCall
    }

    method grill {} {
        puts "Step 1:"
        Foo
        puts "Step 2:"
        bar
    }
}

ABC create abc
abc grill
        \fI\(-> Step 1:\fR
        \fI\(-> This is foo in ::abc\fR
        \fI\(-> Step 2:\fR
        \fI\(-> This is foo in ::abc\fR
# Direct access via the linked command
puts "Step 3:"; ExternalCall
        \fI\(-> Step 3:\fR
        \fI\(-> This is foo in ::abc\fR
.CE
.PP
This example shows that multiple linked commands can be made in a call to
\fBlink\fR, and that they can handle arguments.
.PP
.CS
oo::class create Ex {
    constructor {} {
        \fBlink\fR a b c
        # The methods a, b, and c (defined below) are all now
        # directly acessible within methods under their own names.
    }

    method a {} {
        puts "This is a"
    }
    method b {x} {
        puts "This is b($x)"
    }
    method c {y z} {
        puts "This is c($y,$z)"
    }

    method call {p q r} {
        a
        b $p
        c $q $r
    }
}

set o [Ex new]
$o 3 5 7
        \fI\(-> This is a\fR
        \fI\(-> This is b(3)\fR
        \fI\(-> This is c(5,7)\fR
.CE
.SH "SEE ALSO"
interp(3tcl), my(3tcl), oo::class(3tcl), oo::define(3tcl)
.SH KEYWORDS
command, method, object
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