if 0 {
<<TOC>>
----

**Introduction**
[MiHa] 2015-06-13: 
HelloWorld-programs are supposed to be the most simple, working programs of a given language.

But I want to extend such a HelloWorld-program to a one-page - reference-card, <<br>>
that shows all the essential features of the language. <<br>>
If possible, it should also do something useful (and/or funny).

Tcl by itself (without Tk) is quite simple, so an amount of code  
to fill about one printed page should be enough.

Basic features to cover:
   * Comments
   * Output / format
   * Numeric variables
   * String  variables
   * simple calculations / expr
   * if / then / else
   * for - loop,  maybe while-loop
   * foreach

Advanced features (to include if space permits):
   * input / checking the input
   * catch
   * string-operations (e.g. find/extract/replace char in a string, append, delete/split ...)
   * array / list / dict
...

Things to be aware of:
   * comments are commands, so quotes and braces inside need to be balanced
   * when to use / not to use "$" with variablenames ( set i 1; puts $i; incr i $i )

Maybe there already are some programs here in the wiki 
that would qualify for such a refcard-program...

}
----
**Program 1**
======tcl
  # HelloWorld001.tcl - 2015-06-13 - http://wiki.tcl.tk/41268
  # Output string to terminal:

  puts "Hello, World!"

  ### EOF ###
======

**Program 2**
======tcl
 # HelloWorld002.tcl - MiHa - 2015-06-13
 # http://wiki.tcl.tk/41268

 # http://ideone.com/xxx
  puts "Demo:"
  set i 0
  foreach s { Hello , world ! }  { incr i; puts "$i $s" }
 ### EOF ###
======

----
**Output**
======none
Demo:
1 Hello
2 ,
3 World
4 !
======

----
**Remarks**
This is the Alpha-version, there ''will'' be bugs,
so use with caution <<br>>
...

----
'''See also:'''
   * http://wiki.tcl.tk/41210%|%ClockDemo%|%
   * ...

   
<<categories>> Example | Tutorial