turing machine in an LC

[Michael Spencer]

Jeremy Bowers wrote:
> On Tue, 08 Feb 2005 17:36:19 +0100, Bernhard Herzog wrote:

> 
> Now you *can* get at the previous state and write a state-transition
> expression in perfectly legal Python.
> 
> What do you know, generator comprehensions are Turing Complete and list
> comprehensions aren't. I wouldn't have expected that.
> 
I see no difference between LCs and GEs in this respect:

  >>> import itertools as it
  >>>
  >>> def fact_ge(n):
  ...     f = [1]
  ...     f.extend(i*j for i,j in it.izip(xrange(1,1+n), f))
  ...     return f
  ...
  >>> def fact_lc(n):
  ...     f = [1]
  ...     [f.append(i*j) for i,j in it.izip(xrange(1,1+n), f)]
  ...     return f
  ...
  ...
  >>> fact_ge(10)
[1, 1, 2, 6, 24, 120, 720, 5040, 40320, 362880, 3628800]
  >>> fact_lc(10)
[1, 1, 2, 6, 24, 120, 720, 5040, 40320, 362880, 3628800]

Michael