''[[This page is being used to work on building more user-oriented descriptions of the new features of 8.6; please have a bit of care as this is work-in-progress right now]]''

**Included Object Systems**
Tcl 8.6 includes two object systems (that's two more than any previous release of Tcl). But just because we provide them does not mean that your scripts have to change; objects in Tcl are just commands that have a particular way of accessing subcommands that you should already be familiar with:

    :   ''someCommandThatIsAnObject'' '''theSubcommandThatIsAMethod''' ''someArgument1'' ''someArgument2'' …

If you've used Tk, you've used that pattern. If you've used many of Tcl's commands (the [ensemble]s, like [string] or [namespace] or [chan] or [interp]), you've used that pattern.

[TclOO] (also available as a stand-alone package for Tcl 8.5) is designed to be a small, efficient and powerful object system core that is deeply connected into Tcl and into the way that Tcl works logically. It currently does not ship with a substantial class library, but it is designed to offer a base on which other object systems can be built.

[incr Tcl] 4 also ships with Tcl (and it's an example of an object system built on top of [TclOO]). There's a much larger class library available for itcl.

**The Non-Recursive Evaluation Engine**
Tcl 8.6 is in many ways a “stackless Tcl”. This has many subtle consequences.
   1. Tcl can now support very deep recursion (though it usually has a limit of 1000 imposed, which you can control with [interp recursionlimit]).
   2. Tcl can now perform [tailcall%|%tail-calls], which ''replace'' the current procedure call with a call to some other command.
   3. Tcl supports [coroutine]s, a system for allowing you to restructure your programs from continuation-passing style into much more straight-line code (with appropriate [yield]s at the points where you want to stop the coroutine from running while something else is happening).

**Database Support**
We now define a standard interface ([TDBC]) for accessing databases, and ship a few database drivers that support the interface. We also include [SQLite], the database engine that started as a Tcl extension and then escaped into the big bad world!

**New Commands**
[lmap] and [try] and [zlib] and …

***msgcat::mcflset***
Facilates to translate your application using message catalog files by not repeating the locale for each command.

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