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For 2023 (and 2024 ...) - we are now fully retired from IT training.
We have made many, many friends over 25 years of teaching about Python, Tcl, Perl, PHP, Lua, Java, C and C++ - and MySQL, Linux and Solaris/SunOS too. Our training notes are now very much out of date, but due to upward compatability most of our examples remain operational and even relevant ad you are welcome to make us if them "as seen" and at your own risk.

Lisa and I (Graham) now live in what was our training centre in Melksham - happy to meet with former delegates here - but do check ahead before coming round. We are far from inactive - rather, enjoying the times that we are retired but still healthy enough in mind and body to be active!

I am also active in many other area and still look after a lot of web sites - you can find an index ((here))
Loading packages in your Tcl program

In Tcl, extra bundles of code can be loaded from packages which are files of more ... brought in with package require from a folder that's listed in the auto_path variable.

Packages are defined with a package provide in the source code of the package which must be indexed in a file called pkgIndex.tcl. Failure to index will result in Tcl failing to find the package. There's a built in Tcl command called pkg_mkIndex which allows you to generate the index automatically.

Namespaces are technically different to packages, but it'c common practise to define a package in a Tcl namespace to avoid any risk of conflicting names of procedures, and to make it clearer for the maintenance programmer later on to know what's loaded from where.

Example of a program that loads packages - [here]. The packages it loads are [here] (without a namespace and [here] for one with a namespace

(written 2015-10-09)

 
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles
T213 - Tcl/Tk - Libraries, Packages and Namespaces
  [146] example of Tcl namespaces and packages - (2004-12-10)
  [1339] Packages and Namespaces are like Suitcases and Aircraft - (2007-09-09)
  [1529] Tcl - learning how to use namespaces, packages and libraries together - (2008-02-02)
  [2476] Tcl - uplevel to run code at calling level - (2009-10-24)
  [3066] Separating groups of variables into namespaces - (2010-11-24)
  [3417] What is a namespace and why do we need them? - (2011-09-03)
  [3418] Tcl packages, pkg_mkIndex, pkgIndex.tcl -what are they and why use them. - (2011-09-03)


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Course Schedule - October 2015 to June 2016
Open source programming courses - October to December 2015
Black dog day - and Bobby still seeks his new home
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This is a page archived from The Horse's Mouth at http://www.wellho.net/horse/ - the diary and writings of Graham Ellis. Every attempt was made to provide current information at the time the page was written, but things do move forward in our business - new software releases, price changes, new techniques. Please check back via our main site for current courses, prices, versions, etc - any mention of a price in "The Horse's Mouth" cannot be taken as an offer to supply at that price.

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