TCL

TCL is an imperative, interpreted, dynamically typed programming language. The Tool Command Language appeared in 1988. In Tcl, everything is a string.

It is probably best (and completely?) described by the 12 Rules for Tcl.

Basic Syntax by Example ¶

Some nice comparisons of the syntax of many languages can be found at rigaux.org

Hello World ¶

set myVariable "Hallo World!"
puts $myVariable

Loop over a list ¶

% foreach element {1 2 3} {
    puts $element
}

Fibonacci ¶

proc fib {n} {
    if {$n < 2} {
        return $n
    } else {
        return [expr {[fib [expr {$n-2}]] + [fib [expr {$n-1}]]}]
    }
}

for {set x 0} {$x<10} {incr x} {
    puts [fib $x]
}

Comments ¶

TCL uses # as a line comment and does not offer block comments. In fact, they recommend this:

if 0 {
    Any Tcl code to be commented out (with matching braces, of course!)
    or any other kind of text, will be ignored - and even [exit] won't fire
    because it's in braces, so left unevaluated!
}

Source: wiki.tcl.tk/1669

Logical operators ¶

99 bottles of beer ¶

#!/usr/bin/tclsh

# 99.tcl; Tcl version of 99 Bottles of Beer Song

proc findBString { count } {
  return [switch -exact -- $count {
    0       { expr {"No more bottles"}  }
    1       { expr {"1 bottle"}         }
    default { expr {"$count bottles"}   }
  }]
}

set bottles 99
set bString [findBString $bottles]
while {$bottles + 1} {
  puts "$bString of beer on the wall.  $bString of beer."
  incr bottles -1
  if {$bottles + 1} {
    set bString [findBString $bottles]
    puts "Take one down, pass it round, $bString of beer on the wall.\n"
  } else {
    puts "Go to the store and buy some more...99 bottles of beer."
  }
}

Source: 99-bottles-of-beer.net

Argument parsing ¶

See itfParseArgv

Naming schemes ¶

• Variables have to fit to the pattern [_a-zA-Z][_a-zA-Z0-9]*.
• Functions have to fit to the pattern [^ \t\n\r\f]+.
• Variables and function are scrunched together by camelCase or CamelCase.

Community ¶

I think one indicator for the quality of the community is it's size. And the community will grow, when the language gets more popular.

According to Ohloh, TCL is quite unpopular:

• 

  Monthly Commits
• 

  Monthly Contributors
• 

  Monthly Lines of Code
• 

  Monthly Projects

You can also take a look at Google Trends:

• The TIOBE Index ranked Tcl on place 43 in March 2014.
• lang-index ranked Tcl on place 84 in the general category and on place 34 in the script category.
• There are 2,490 Tcl questions on StackOverflow. Compare that to 286,244 questions about Python or 609,648 questions about Java.
• Tcl is on rank 18 for GitHub (source).

Execution Speed ¶

Speed comparisons of programming languages are difficult. One nice way to compare the execution speed of programming languages is the benchmarksgame. But sadly, they don't have TCL.

Additional information ¶

• Official website
• Wikipedia