[Tutor] Re: Python vs. Ruby

[Gregor Lingl]

...

>In Ruby, you can subclass everything, modify all classes, call methods on
>everything.
>
>Ruby              Python
>=====================================
>2.times do        for i in range(2):
>    puts "ok"         print "ok"
>end
>- - - - - - - - - - - - - - - - - - -
>ok                ok
>ok                ok
>=> 2
>=====================================
>5.0.+(3)          5.0 + 3
>- - - - - - - - - - - - - - - - - - -
>=> 8.0            8
>  
>
at least this last example is not so much different from Python:

 >>> 5.0.__add__(3)
8.0
 >>>
which shows that in Python + also is only some sort of syntactical
sugar.

On the other hand there are types of objects, e.g. type 'function',
which cannot be subclassed as far as I know (and regret).

Testtask: is it possible to subclass (numerical)  functions - say this
new class is named Fun - e.g. by adding a __add__ method, in a
way that their instances can be added, like:
 >>> from math import sin, cos
 >>> f = Fun(sin) + Fun(cos)   ### see remark below
 >>> f(1)
#### should output sin(1)+cos(1)
In short: it would be nice to create some sort of function algebra.

In Python this seems a bit weird because of the special
way functions are defined (namely via the reserved word def).
So how should (or could) one define a "fun"? Maybe by making
it "callable" somehow? (Oh, I feel that this is not a very sharply
defined problem ...)

Is a task of this sort more easily ( and/or more
in accordance with the philosophy of the language)
solvable in Ruby?

Gregor