** Summary ** 

How to use and manage Tcl packages.

** See Also **

[Tcl User Guide%|%User Guide%|%]

[Tcl Package Developer Guide%|%Package Developer Guide%|%]

[Teapot]:   A package distribution system, for [ActiveState::ActiveTcl] 


** Description **

In the most elementary case, using a package is a matter of directly employing
the [load] or [source] command to make the code in some file available to Tcl.
This can be seen in the following examples:

[extension example]

Typically, however, packages are distributed such that they can be loaded via the [package] command.

** Installing packages **

   [Just getting a package found already]:   

[LV] Another common encounter is getting "can't find" and the cause is that the
directory in which it was installed isn't on $auto_path , or perhaps the
pkgIndex.tcl contains code that just doesn't work. In fact, I've seen cases
where syntax code in one package's pkgIndex.tcl caused tcl problems when some
other package was required....

[Where does the package command find the packages it seeks?]:   


** Building Packages **

[Building an extension for Tcl under Mac OS X]

[How to build for WinCE]


** Unloading a Package **

[How to unload a package]:   

** List of Currently Loaded Packages **

======
proc packages {} {
    # returns the list of presently loaded packages
    set res {}
    foreach i [package names] {
        if {[string length [package provide $i]]} {
            lappend res $i
        }
    }
    set res
} ;# RS
======


[LV] Is there a way to modify this packages proc so that it also reports the
version of the package that was loaded?

[Lars H]: Yes, simply change the

======
lappend res $i
======

line to

======
lappend res $i [package provide $i]
======

** Report Package Versions **

[RS] 2006-01-29: Here's a package version retriever that returns a list, which
can be put into a [dict] or [array]:

======
proc packages {{pattern *}} {
        catch {package require ""}
        set res {}
        foreach p [lsort [package names]] {
                if [string match $pattern $p] {
                        lappend res $p [package versions $p]
                }
        }
        set res
}
======

Incidentally, packages [Tcl] and [ActiveTcl] report {} at [package versions],
seen on 8.4.5 and 8.4.12. At least the former could do the same as what [info
patchlevel] does... [Tk] says 8.4 at least, but there are many precedents of
packaging reporting 3-part version numbers, [Mk4tcl] even does four: 2.4.9.2.
Test:
======none
% foreach {p v} [packages T*] {puts "$p : $v"}
Tcl :
TclScript : 1.0
Tclx : 8.4
Tk : 8.4
Tkhtml : 2.0
Tktable : 2.8
Tkx : 8.3
Trf : 2.1
======

** Modules **

See also [Tcl modules] for possibly new alternatives to packages. Then there is
[kitten], which is an example of storing packages in a single [starkit] which
is easier to ship around.


** Misc **

[Package tips and tricks]:   

[package equivalences]:   [jcs]: a page  to sort out issues regarding packages which need to co-exist, such as binaries with a fallback to a pure Tcl implementation.



<<categories>>