Programming D. E. Knuth in Python with the Deterministic Finite Automaton construct

Sat Mar 17 22:59:31 EDT 2012

On 3/17/2012 9:03, Antti J Ylikoski wrote:
>> In his legendary book series The Art of Computer Programming,
> Professor Donald E. Knuth presents many of his algorithms in the form
> that they have been divided in several individual phases, with
> instructions to GOTO to another phase interspersed in the text of the
> individual phases.
>>> A1. (Do the work of Phase A1.) If <zap> then go to Phase A5,
> otherwise continue.
>> A2. (Do some work.) If <zorp> go to Phase A4.
>> A3. (Some more work.)
>> A4. (Do something.) If <condition ZZZ> go to Phase A1.
>> A5. (Something more). If <foobar> then go to Phase A2, otherwise
> end.

Clearly you just need the goto module (http://entrian.com/goto/):
 from goto import goto, label
 label .A1
 # do work of phase A1
 if <zap>: goto .A5
 label .A2
 # do some work
 if <zorp>: goto .A4
 # do some more work
 label .A4
 # do something
 if <condition zzz>: goto .A1
 label .A5
 # something more
 if <foobar>: goto .A2
Clearly the best solution of all.
(Note: do not actually do this.)
Evan
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