# tcl::transform::core(3tcl) 1 virtchannel_core "Reflected/virtual channel support"

## Name

tcl::transform::core - Basic reflected/virtual channel transform support

## Table Of Contents

## Synopsis

- package require Tcl 8.5
- package require TclOO
- package require tcl::transform::core ?1?

- ::tcl::transform::core objectName
- objectName initialize thechannel mode
- objectName finalize thechannel
- objectName destroy

## Description

The tcl::transform::core package provides a TclOO class implementing common behaviour needed by virtually every reflected or virtual channel transformation (initialization, finalization).

This class expects to be used as either superclass of a concrete channel class, or to be mixed into such a class.

## Class API

::tcl::transform::core objectName

  This command creates a new transform core object with an associated global Tcl command whose name is objectName. This command may be used to invoke various operations on the object, as described in the section for the Instance API.

## Instance API

The API of transform core instances provides only two methods, both corresponding to transform handler commands (For reference see TIP 230). They expect to be called from whichever object instance the transform core was made a part of.

objectName initialize thechannel mode

  This method implements standard behaviour for the initialize method of transform handlers. Using introspection it finds the handler methods supported by the instance and returns a list containing their names, as expected by the support for reflected transformation in the Tcl core.

  It further remembers the channel handle in an instance variable for access by sub-classes.

objectName finalize thechannel

  This method implements standard behaviour for the finalize method of channel handlers. It simply destroys itself.

objectName destroy

  Destroying the transform core instance closes the channel and transform it was initialized for, see the method initialize. When destroyed from within a call of finalize this does not happen, under the assumption that the channel and transform are being destroyed by Tcl.

## Bugs, Ideas, Feedback

This document, and the package it describes, will undoubtedly contain bugs and other problems. Please report such in the category virtchannel of the Tcllib Trackers. Please also report any ideas for enhancements you may have for either package and/or documentation.

## Keywords

reflected channel, tip 219, virtual channel

## Category

Channels

## Copyright

Copyright © 2009 Andreas Kupries <andreas_kupries@users.sourceforge.net>