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self(n)                         TclOO Commands                         self(n)

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NAME
       self - method call internal introspection

SYNOPSIS
       package require TclOO

       self ?subcommand?
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DESCRIPTION
       The self command, which should only be used from within the context of
       a call to a method (i.e. inside a method, constructor or destructor
       body) is used to allow the method to discover information about how it
       was called. It takes an argument, subcommand, that tells it what sort
       of information is actually desired; if omitted the result will be the
       same as if self object was invoked. The supported subcommands are:

       self call
              This returns a two-element list describing the method            |
              implementations used to implement the current call chain. The    |
              first element is the same as would be reported by info object    |
              call for the current method (except that this also reports       |
              useful values from within constructors and destructors), and the |
              second element is an index into the first element's list that    |
              indicates which actual implementation is currently executing     |
              (the first implementation to execute is always at index 0).

       self caller
              When the method was invoked from inside another object method,
              this subcommand returns a three element list describing the
              containing object and method. The first element describes the
              declaring object or class of the method, the second element is
              the name of the object on which the containing method was
              invoked, and the third element is the name of the method (with
              the strings <constructor> and <destructor> indicating
              constructors and destructors respectively).

       self class
              This returns the name of the class that the current method was
              defined within.  Note that this will change as the chain of
              method implementations is traversed with next, and that if the
              method was defined on an object then this will fail.

              If you want the class of the current object, you need to use
              this other construct:

                     info object class [self object]

       self filter
              When invoked inside a filter, this subcommand returns a three
              element list describing the filter. The first element gives the
              name of the object or class that declared the filter (note that
              this may be different from the object or class that provided the
              implementation of the filter), the second element is either
              object or class depending on whether the declaring entity was an
              object or class, and the third element is the name of the
              filter.

       self method
              This returns the name of the current method (with the strings
              <constructor> and <destructor> indicating constructors and
              destructors respectively).

       self namespace
              This returns the name of the unique namespace of the object that
              the method was invoked upon.

       self next
              When invoked from a method that is not at the end of a call
              chain (i.e. where the next command will invoke an actual method
              implementation), this subcommand returns a two element list
              describing the next element in the method call chain; the first
              element is the name of the class or object that declares the
              next part of the call chain, and the second element is the name
              of the method (with the strings <constructor> and <destructor>
              indicating constructors and destructors respectively). If
              invoked from a method that is at the end of a call chain, this
              subcommand returns the emtpy string.

       self object
              This returns the name of the object that the method was invoked
              upon.

       self target
              When invoked inside a filter implementation, this subcommand
              returns a two element list describing the method being filtered.
              The first element will be the name of the declarer of the
              method, and the second element will be the actual name of the
              method.

EXAMPLES
       This example shows basic use of self to provide information about the
       current object:

              oo::class create c {
                  method foo {} {
                      puts "this is the [self] object"
                  }
              }
              c create a
              c create b
              a foo                -> prints "this is the ::a object"
              b foo                -> prints "this is the ::b object"

       This demonstrates what a method call chain looks like, and how
       traversing along it changes the index into it:

              oo::class create c {
                  method x {} {
                      puts "Cls: [self call]"
                  }
              }
              c create a
              oo::objdefine a {
                  method x {} {
                      puts "Obj: [self call]"
                      next
                      puts "Obj: [self call]"
                  }
              }
              a x     -> Obj: {{method x object method} {method x ::c method}} 0
                      -> Cls: {{method x object method} {method x ::c method}} 1
                      -> Obj: {{method x object method} {method x ::c method}} 0

SEE ALSO
       info(n), next(n)

KEYWORDS
       call, introspection, object

TclOO                                 0.1                              self(n)