tk special variables

[Alan Lake]

How does one refer to a tk special variable in Ruby? In Perl, it is
$Tk::<variable>. What tk special variables are available in Ruby? I'm
referring to variables like patchLevel, strictMotif, VERSION and
version.

In /usr/lib/ruby/1.8/tk.rb, I found TCL_VERSION, TCL_PATCHLEVEL,
TCL_MAJOR_VERSION, TCL_MINOR_VERSION, TK_VERSION, TK_PATCHLEVEL,
TK_MAJOR_VERSION, TK_MINOR_VERSION and JAPANIZED_TK. This may be what
I'm looking for, but these are constants, not variables.

When I try to refer to them (in irb), but after saying
require 'tk'
I have tried as many different ways as I can...
puts tk::TK_VERSION
puts TK_VERSION
puts TK::TK_VERSION

 

[Stefano Crocco]

Alle sabato 3 marzo 2007, Alan Lake ha scritto:

How does one refer to a tk special variable in Ruby? In Perl, it is
$Tk::<variable>. What tk special variables are available in Ruby? I'm
referring to variables like patchLevel, strictMotif, VERSION and
version.

In /usr/lib/ruby/1.8/tk.rb, I found TCL_VERSION, TCL_PATCHLEVEL,
TCL_MAJOR_VERSION, TCL_MINOR_VERSION, TK_VERSION, TK_PATCHLEVEL,
TK_MAJOR_VERSION, TK_MINOR_VERSION and JAPANIZED_TK. This may be what
I'm looking for, but these are constants, not variables.

When I try to refer to them (in irb), but after saying
require 'tk'
I have tried as many different ways as I can...
puts tk::TK_VERSION
puts TK_VERSION
puts TK::TK_VERSION

I know nothing of tk, but the constants you looked for are in module Tk, not
TK and not tk (which can't be a module name since it doesn't begin with an
uppercase character). So, you should do:

require 'tk'
puts Tk::TK_VERSION
...

Looking at the names of the variables you mentioned (keeping in mind that I
don't know tk), I think there's a good reason for which they're constants:
for instance, TK_VERSION is the version of tk you have on your system, so I
can't think of a reason to change them.

By the way, to get the names of the constants (including classes and modules)
defined in a class or module, you can use the constants method of the Module
class. If you call it as a class method of the module class (i.e
Module.constants), it will return an array with the top-level constants. If
you call it as an instance method of a class / module it will return the
names of the constants defined in it. In your case:

require 'tk'
Module.constants.sort
=> ["ARGF", "ARGV", "ArgumentError", "Array", ..., "Tk", "TkAfter", ...]

This tells you the module you needed is called Tk. To know the constants
defined in the Tk module, you can do:

Tk.constants.sort
=> ["AUTO_PATH", "BinaryString", ..., "TK_PATCHLEVEL", "TK_VERSION", ...]

I hope this helps

Stefano