Training, Open Source Computer Languages

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For 2021 - online Python 3 training - see ((here)).

Our plans were to retire in summer 2020 and see the world, but Coronavirus has lead us into a lot of lockdown programming in Python 3 and PHP 7.
We can now offer tailored online training - small groups, real tutors - works really well for groups of 4 to 14 delegates. Anywhere in the world; course language English.

Please ask about private 'maintenance' training for Python 2, Tcl, Perl, PHP, Lua, etc.
Brackets and Braces in Tcl


One of the big issues that newcomers feel is most difficult to get their head around in Tcl is when to use square brackets, when to use round brackets, and when to use curly braces.


SQUARE BRACKETS are used to define a block that's run BEFORE the rest of the command on the current line, and the result is substituted into the line.

CURLY BRACES are used to define a block that's deferred - in other words it may be run AFTER the rest of the command on the current line.


ROUND BRACKETS are different - they're used either to indicate an array subscript, or to alter operator precedence in an expr command. They are not used in command precedence.

How do I help people remember this? I often equate the Square brackets with the very irritating Donkey in the Shrek Movies that always saying "Pick me ... pick me" ... an irritating but, as it turns out, very necessary and faithful friend.

Donkey Week Horseshoe Sidmouth 2005

This image is reproduced with permission of where painted horseshoes are offered for sale in support of The Donkey Sanctuary, near Sidmouth, Devon

See also Tcl training course

Please note that articles in this section of our web site were current and correct to the best of our ability when published, but by the nature of our business may go out of date quite quickly. The quoting of a price, contract term or any other information in this area of our website is NOT an offer to supply now on those terms - please check back via our main web site

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Solutions centre home page

You'll find shorter technical items at The Horse's Mouth and delegate's questions answered at the Opentalk forum.

At Well House Consultants, we provide training courses on subjects such as Ruby, Lua, Perl, Python, Linux, C, C++, Tcl/Tk, Tomcat, PHP and MySQL. We're asked (and answer) many questions, and answers to those which are of general interest are published in this area of our site.

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