Path: csiph.com!usenet.pasdenom.info!weretis.net!feeder1.news.weretis.net!feeder.erje.net!newsfeed.xs4all.nl!newsfeed6.news.xs4all.nl!xs4all!newsgate.cistron.nl!newsgate.news.xs4all.nl!post.news.xs4all.nl!not-for-mail
Return-Path: <driscoll@cs.wisc.edu>
X-Original-To: python-list@python.org
Delivered-To: python-list@mail.python.org
X-Spam-Status: OK 0.040
X-Spam-Evidence: '*H*': 0.92; '*S*': 0.00; 'subject:Python': 0.05; 'content-type:multipart/signed': 0.09; 'filename:fname piece:signature': 0.09; '(do': 0.16; '(note:': 0.16; 'a2,': 0.16; 'antti': 0.16; 'content-type:application/pgp-signature': 0.16; 'filename:fname piece:asc': 0.16; 'filename:fname:signature.asc': 0.16; 'goto,': 0.16; 'phases.': 0.16; 'subject: \n ': 0.16; 'subject:Programming': 0.16; 'wrote:': 0.18; 'to:2**1': 0.21; 'header:In-Reply-To:1': 0.22; 'module': 0.26; 'import': 0.27; 'url:)': 0.29; 'goto': 0.30; 'actually': 0.31; 'header:User- Agent:1': 0.33; 'programming,': 0.34; 'all.': 0.34; 'algorithms': 0.34; 'end.': 0.34; 'to:addr:python-list': 0.35; 'something': 0.35; 'to:name:python-list': 0.37; 'another': 0.37; 'subject:with': 0.37; 'received:128': 0.38; 'received:192': 0.38; 'some': 0.38; 'several': 0.38; 'clearly': 0.39; 'to:addr:python.org': 0.40; 'more': 0.61; 'art': 0.61; 'subject:. ': 0.63; 'donald': 0.67; 'series': 0.67; 'presents': 0.71; 'divided': 0.73; 'phase': 0.82; 'knuth': 0.84; 'more).': 0.84; 'url:goto': 0.84
Date: Sat, 17 Mar 2012 21:59:31 -0500
From: Evan Driscoll <driscoll@cs.wisc.edu>
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:10.0.2) Gecko/20120216 Thunderbird/10.0.2
MIME-Version: 1.0
To: Antti J Ylikoski <antti.ylikoski@tkk.fi>, python-list <python-list@python.org>
Subject: Re: Programming D. E. Knuth in Python with the Deterministic Finite Automaton construct
References: <gR09r.22645$I33.16090@uutiset.elisa.fi>
In-Reply-To: <gR09r.22645$I33.16090@uutiset.elisa.fi>
X-Enigmail-Version: 1.4
Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig9C55FFF1FB2BDE6E723C8B0D"
X-BeenThere: python-list@python.org
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: General discussion list for the Python programming language <python-list.python.org>
List-Unsubscribe: <http://mail.python.org/mailman/options/python-list>, <mailto:python-list-request@python.org?subject=unsubscribe>
List-Archive: <http://mail.python.org/pipermail/python-list>
List-Post: <mailto:python-list@python.org>
List-Help: <mailto:python-list-request@python.org?subject=help>
List-Subscribe: <http://mail.python.org/mailman/listinfo/python-list>, <mailto:python-list-request@python.org?subject=subscribe>
Newsgroups: comp.lang.python
Message-ID: <mailman.773.1332040943.3037.python-list@python.org>
Lines: 74
NNTP-Posting-Host: 2001:888:2000:d::a6
X-Trace: 1332040943 news.xs4all.nl 6909 [2001:888:2000:d::a6]:35290
X-Complaints-To: abuse@xs4all.nl
Xref: csiph.com comp.lang.python:21849

This is an OpenPGP/MIME signed message (RFC 2440 and 3156)
--------------enig9C55FFF1FB2BDE6E723C8B0D
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable

On 3/17/2012 9:03, Antti J Ylikoski wrote:
>=20
> 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.
>=20
>=20
> A1.  (Do the work of Phase A1.)  If <zap> then go to Phase A5,
> otherwise continue.
>=20
> A2.  (Do some work.) If <zorp> go to Phase A4.
>=20
> A3.  (Some more work.)
>=20
> A4.  (Do something.)  If <condition ZZZ> go to Phase A1.
>=20
> 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


--------------enig9C55FFF1FB2BDE6E723C8B0D
Content-Type: application/pgp-signature; name="signature.asc"
Content-Description: OpenPGP digital signature
Content-Disposition: attachment; filename="signature.asc"

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.10 (MingW32)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/

iQEcBAEBAgAGBQJPZU+ZAAoJEAOzoR8eZTzgx6YH/1r43y6XWZixjFMgw8w4KFrO
gQdYN1sB/sjfjkMnqf8QmN7GKAlXWe9QxuqqqIB1E7dqNrIYwLgbhM2KaQe72huU
NSAlpSjbBeZNYnpZOYE0ITGQxKfpHV+b82FAGUYHMOoK4uJEpUQhmE5FBMW/+T82
3AF+mNSJddDbP/qEUv8x9BSjPuzl4NuC4Q1epnYJU7WQySvg4OM+UWDENaTEGTtq
VDYUDRRkbjHnZ0iSA9YLge44yehdHchAx+K6DKvnmwSHsD8Ozsy2z3gRbG2nd1Rq
0EBesNyYYlsJOUPJyec2BLw4AXGK9MfIbu38JHeS1lxPxuoMtBK++TlJuYkWGAk=
=Gb8C
-----END PGP SIGNATURE-----

--------------enig9C55FFF1FB2BDE6E723C8B0D--