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 Our training notes are now very much out of date, but due to upward compatability most of our examples remain operational and even relevant ad you are welcome to make us if them "as seen" and at your own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)) |
Tcl variable names - no real limits!
In Tcl, there are no limits as to what you use as a vaiable name in Tcl, although I would reommend that you stick with "letter, followed by letters, digits, underscores". Here are some examples of thinks you can, but should not, write:
% set " " ohdear!
ohdear!
% puts ${ }
ohdear!
%
%
% set 7 34
34
% puts $7
34
%
% set print puts
puts
%
% $print "Hello World"
Hello World
%
Remember that in Tcl, you put s $ in front of a varioable name if you're just using the existing content, and no $ if you;re setting (or in a syntax where it will possibly be set) (written 2015-03-10, updated 2015-03-11)
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles T202 - Tcl/Tk - Tcl Fundamentals [3] Looking for a donkey - (2004-08-05) [210] Joining lists in Tcl. Indirect variables in Tcl. - (2005-02-12) [328] Making programs easy for any user to start - (2005-05-29) [349] Comments in Tcl - (2005-06-16) [362] The ireallyreallywanna operator - (2005-06-28) [782] Converting between Hex and Decimal in Tcl - (2006-06-28) [1136] Buffering output - why it is done and issues raised in Tcl, Perl, Python and PHP - (2007-04-06) [1282] Stringing together Tcl scripts - (2007-07-29) [1426] Buffering up in Tcl - the empty coke can comparison - (2007-11-10) [1469] Curley brackets v double quotes - Tcl, Tk, Expect - (2007-12-12) [2442] Variable storage - Perl, Tcl and Python compared - (2009-10-08) [3917] BODMAS - the order a computer evaluates arithmetic expressions - (2012-11-09) [4324] Learning to program - variables and constants - (2014-11-22)
Some other Articles
Test framework for TCL - Tcltest - some examplesObjects in Tcl - iTcl - updated first steps exampleWorking out distance between places, using OS grid references and a program in TclEverything is a string - even a listTcl variable names - no real limits!Binary data handling - Python and PerlRunning an operating system command from your Python program - the new way with the subprocess moduleDeciding whether to use parameters, conditional statements or subclassesSpike solution, refactoring into encapsulated object methods - good design practiseWhat is the difference between a function and a method?
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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.
Link to Ezine home page (for reading).
Link to Blogging home page (to add comments).
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