Agreed. I find it quite a bit more elegant overall, and I decided to just jump in and do my throwaway scripts in Lua and see how much of a difference that makes. If I like it enough to write a few small libraries along the way, everybody wins.

Lua has tail-call elimination, coroutines, closures, and lambdas. I'm pretty sure Python has none of these, except for (possibly) a limited form of coroutines. (The Python lambda is too crippled, its closures are broken.) Lua is also one of the most deliberately portable languages I've seen, too. I have a hunch it would be a great language for bootstrapping a Lisp or Scheme compiler, though I haven't tried this yet.

   >>> def makeAdder(x):
   	def inc(y):
   		return y+x
   	return inc
   
   >>> f = makeAdder(3)
   >>> f(4)
   7

   >>> def makeAdder2(x):
   	v = x
   	def inc(y):
   		v += y
   		return v
   	return inc
   
   >>> f2 = makeAdder2(3)
   >>> f2(4)
   
   Traceback (most recent call last):
     File "<pyshell#15>", line 1, in <module>
       f2(4)
     File "<pyshell#13>", line 4, in inc
       v += y
   UnboundLocalError: local variable 'v' referenced before assignment
   >>>

--

In Lua:

  > function adder(x)
      local v = x
      function inc(y)
          v = v + y
          return v
          end
      return inc
      end
  >> >> >> >> >> >> >> > f = adder(3)
  > =f(4)
  7
  > =f(4)
  11
  > =f(4)
  15
  >

def makeAdder2(x):

    v = [x,]
    def inc(y):
        v[0] += y
   	return v[0]
    return inc

def makeAdder2(x):

    def inc(y, v=[x,]):
        v[0] += y
   	return v[0]
    return inc

Good to know it's possible, though I'd rather it handle closures / lexical scoping directly.

Generally I do not mutate variables as far as possible, so I have not hit this problem myself, yet. Perhaps there is someone more knowledgeable about Python to step in.