From: Ferenc Engard <engard@...>
Date: 2002-08-25T05:40:44+09:00
Subject: interactive ruby/tk app (was: ruby/tk internals)

Hello,

I am trying to achieve the same thing what is the default in tck/tk: I
start the application, and afterwards I can execute statements, changing
the user interface, creating new objects.

My first thought was the following:

------------------------------------------
evalFrame=TkFrame.new { pack }
evalBox=TkText.new(evalFrame) {
    height 10
    pack('fill'=>'x')
}
evalBtn=TkButton.new(evalFrame) {
    text "Execute"
    command proc {evalText(evalBox.value)}
    pack()
}

def evalText(text)
    puts eval text
end
------------------------------------------

The problem is, if I create a new Tk object runtime (a TkButton, for
example), I cannot store it into a local variable, as I will not be able
to reference that (was-local) variable.

While I was writing this mail, it came to my mind that I can pass a
Binding object to eval(). So, the solution is:

------------------------------------------
$topContext=binding()
....
def evalText(text)
    puts eval text, $topContext
end
------------------------------------------

It looks better. Are there other (more pretty :) solutions? 

Bye:
Circum