Tk was very handy for whipping up GUI apps. However those comparison examples written in Perl (not Pearl!), Ruby & Python could be improved to look (at least a little!) better.
For a completely different comparison (non Tk) here is the first example (http://www.tkdocs.com/tutorial/firstexample.html) written in Rebol:
Rebol []
convert-to-metres: func [in-feet] [
(round 0.3048 * in-feet * 10000.0) / 10000.0
]
default-feet: 1
my-window: layout [
style input-feet field 80 left
style label lab 90 left
tabs [140 230]
across
tab feet: input-feet (to-string default-feet)
tab label "feet"
return
text "is equivalent to"
tab in-metres: text (to-string convert-to-metres default-feet)
tab label "metres"
return
tabs 230
tab button "calculate" [
in-metres/text: to-string convert-to-metres to-decimal feet/text
show in-metres
]
]
view/title my-window "Feet to Metres"
The above is written in the Visual Interface Dialect of Rebol 2. I made it look visually
identical to the example provided however this was the first time I've ever written any VID code so I'm sure it can be improved upon :)