Tcl, or Tool Command Language, will not be found in the ‘most popular languages’ hall of fame. That is partly because of its ‘wierd’ syntax. But those who know Tcl will tell you that Tcl is a pleasure to work with. I have a special interest in Tcl – its the language that introduced me to GUI programming(Tcl/Tk). Now, when ever I see a GUI toolkit, I compare it to Tcl.

I have a few years experience in Tcl – I have written a very popular Tcl/Tk Tutorial and also a few small applications in Tcl. I am not using it a lot now a days because Tk apps look really bad in Linux. This problem is not present in Windows.

Hello Code

#!/usr/bin/tclsh

# Printing(IO)
puts "Hello World!\n" 

# Variables, concatenation
set name 'Binny'
set year 2008
puts [concat "Hello, "  $name  " - welcome to "  $year]

#If,else conditions
if { $year > 2008 } {
	 puts "Welcome to the future - yes, we have flying cars!" 

} elseif { $year < 2008 }  {
	 puts "The past - please don't change anything. Don't step on any butterflies. And for the sake of all that's good and holy, stay away from your parents!" 

} else {
	 puts "Anything wrong with your time machine? You have not gone anywhere, kiddo."
}

# For loop
for { set i 0 } { $i<3 } { incr i  }  {
	 puts "$i) Hi there!"
}

#Numerical Array, foreach
set rules [list "Do no harm" "Obey" "Continue Living"]

set i 0
while { $i < [llength $rules] } {
	puts [concat "Rule " [expr $i+1] " : "  [lindex $rules $i]]
	incr i
}

# Associated array, while
array set associated {
	hello	"world"
	foo		"bar"
	lorem	"ipsum"
}

foreach key [array names associated] {
	 puts [concat $key " : " $associated($key)]
}

# Using Join and Split
set csv_values [split "hello,world,how,are,you\n" ","]
puts [join $csv_values ":"]

# Function, argument, return, call
proc hello { person_name } {
	return [concat "Hello, " $person_name]
}
puts [hello "Binny"]

# File IO
# File reading, easy method...
set IN [open "Hello.tcl" r]
set contents [read $IN]
close $IN
puts [concat "Hello has " [string length $contents] " chars"]

# Writing to a file
set OUT [open "/tmp/hello.txt" w]
puts $OUT "Hello World"
close $OUT

# Regular Expressions
set str "Hello World"
if { [regexp {^Hell} $str] } {
	puts "Yup, its evil"
}

puts [regsub -all {l([^l])} $str {\1}]

# Special Tcl Syntax
# Math ops
set answer [expr {3 + 2}]

# Comments
puts $answer ;# Comments in the same line as code must use ;# instead of just #

Tcl/Tk Links

• Tcl Developer Xchange
• Tcler’s Wiki
• Tcl in Wikipedia
• I can’t believe I’m praising Tcl

But when I actually ran the programs in Linux, I got the shock of a lifetime. The applications I created looked bad – really bad…

I still use many Tk programs – but because of the looks issue, I decided to stop using Tk for my new programs. So I decided to try GTK. I even created a small application using PyGTK(my first) to view the harddisk space usage in Linux – Frees.

It was a very simple application – all I had to do is run the ‘df’ command, parse its output, and display a small table using that data. I was expecting around 100, 150 lines of code at the most. But after I created the app, I have 500+ lines of code.

At first, I thought that it was a mistake on my part – I thought that I was not using the best method. But then I came across an article in Reddit – gnocl or PyGtk?.

PyGtk is still the most recommended binding for Gtk. A lot of programs in Linux is written using PyGtk. So naturally there are a few advantages for using it…

• It will be the more ‘road-tested’ binding.
• Many system will have it installed by default.
• Bigger community – so…
  • more support
  • more examples
  • more tutorials
  • etc.

One the other hand, I have to write more code.

Conclusion

If it is a private script – only useful for myself, then I will use Tcl/Tk or Gnometcl. If the script could be distributed, like Frees, then I will use Python GTK.

What about the other options…

• wxWidgets
• PyQT
• Ruby/GTK
• Perl/GTK

Any recommendations for me on which library to use? Please leave it in the comments.