The code below, which puts "Hello" in a label on press of a button,
works if the command for the button is { a.value = "Hello" }, but not if
it is { a = "Hello" }.  I'm trying to understand "why", and can't find
anything on the ".value" method in in the Pragmatic Programmers' book on
Ruby.

Can someone explain why {a = "Hello"} won't work, and why I need to do
{a.value = "Hello"?}

Thanks in advance.

------------------------------------
require 'tk'

root = TkRoot.new.title("Example")

a = TkVariable.new
Labels = TkLabel.new(root) do
  textvariable a
  pack('side' => "top")
end

TkButton.new(root) do
  text "Press"
  command { a.value = "Hello" }
  pack('side' => "top")
end

Tk.mainloop
----------------------------

-- 
Posted via http://www.ruby-forum.com/.