[Xotcl] XOTcl 0.9

[Gustaf Neumann]

Fellow XOTcl community,

here comes the annoucemnt of XOTcl 0.9.

best regards
-gustaf neumann
.uwe zdun
==================================================================================

Announcing XOTcl 0.9
********************

WHAT IS XOTCL?

  XOTcl is an object-oriented extension of Tcl that was derived from
  OTcl. In short, XOTcl tries to provide a highly flexible,
  reflective, component-based, and object-oriented environment. It
  integrates language support for high level concepts which are not
  found in other languages, with reasonable performance. It prevails
  the Tcl programming style and the dynamic/introspective nature of
  the language, rather than introducing other language's styles and
  rigidness (such as C++) into Tcl.


RECENT CHANGES relative to 0.85 are:

  - new functionality:

    * Per object filters: in addition to traditional filters
      (which are called now "instfilters") one can define now
      filters per objects as well. XOTcl supports now
      the following interceptors: per class filters and
      mixins (called instfilters and instmixins), 
      and per object filters and mixins (called filters and 
      mixins).

    * filterguards: 
      This is a new mechanism to specify when filters
      should be applied (see tutorial and language reference). 

    * Namespace transparency for XOTcl procs and instprocs:
      In previous releases, the programmer was responsible
      to use :: prefixes in order to safely address Tcl commands
      from XOTcl (e.g. an instance of a class defining 
      "set" had to use ::set). Now, the namespaces of Classes 
      and objects are ignored for command resolutions avoiding
      potential interferences.

    * Namespace on demand: 
      XOTcl objects allocate namespaces on demand 
      (e.g. when procs or child objects are defined).

    * XOTcl is now a "well behaved" extension:
      When libxotcl is loaded everything resides in 
      the ::xotcl namespace. Use "namespace import xotcl::*" 
      to import the global commands (xotclsh and xowish do 
      this per default).

    * Improved parameter settings (see tutorial)


  - Speed improvements: 
    * Significant speedup through the more consequent use
      of Tcl_Objs for accessing classes and objects.

    * Methods for append/lappend/array etc. are about 3 times
      faster through the use of insttclcmd (see below)

    * Parameter methods:
      Methods for accessing parameters are now 4 to 5 times faster.
      In the following example, "name" and "age" are parameters:
        Class Person -parameter {{age 0} name}
        Person p1 -age 99 -name gustaf
	puts [p1 age]
      setting and retrieving of parameters has now roughly the same
      speed as the set methods


  - Reduced memory consumption for objects and classes:

    The size of XOTclObject structure went from 172 bytes 
    to 48 bytes by 

      * allocating assertion structures and namespaces on demand, and 
      * by and by omitting in the default setup metadata

    10 thousand XOTcl objects consume now on a 32bit machine
    about 2 MB of memory in total (including whatever Tcl needs 
    for commands etc)


  - new Class methods
    * instparametercmd: define a new getter/setter for instance 
      variables for instances of used class
    * insttclcmd: evaluate an Tcl command in the context of an object

  - new Object methods:
    * parametercmd: define a new getter/setter for instance 
      variables for an object
    * configure: method to call a series of methods on an object
      e.g.
       Object o1
       o1 configure -set x 1 -set y 2 


  - new subcommands for info method: 
    * info methods:
      returns procs, commands and mixins, accepts 
      modifiers: -noprocs, -nocmds, -nomixins
    * info instfilters
    * info filter 
      accepts new modifiers: -guards, -order




  - fixes:
     * propagation of return codes (e.g. ... return -code continue ...)
       which is needed for Tk event maps

     * various actiweb fixes (agent migration was broken)

     * improved documentation


  - Support for AOLserver:
 
    XOTcl is now prepared for use in the AOL-server. The stubs for
    AOL-server are integrated in XOTcl (many thanks to 
    Zoran Vasiljevic). The required patch for the AOL-Server 
    is available from http://media.wu-wien.ac.at/download.html#aol


  - Stub-library support:

    XOTcl supports now the stub library. This means that
    it is less dependent on particular Tcl implementations.
    The support was quite tricky since some commands used by XOTcl
    (like Tcl_IncrObjCmd, Tcl_UpvarObjCmd, ...) are 
    not exported by the stub library, and the solution
    has to work in the multithreaded AOL-server environment)



  - potential incompatibilities:
    * "[self] next" is gone, use "next" instead.
    * The access of instance variables through the
      tcl-set command is deprecated and works only
      when the namespace is created. Instead of 
         Object o
         set o::x 1
      use 
         Object o
         o set x 1
    * procsearch returns a different format (see Changelog)



MORE INFO
  General and more detailed information about XOTcl and its components
  can be found at http://www.xotcl.org


Best regards,

Gustaf Neumann
Uwe Zdun