Python 3 regex?
Steven D'Aprano
steve at pearwood.info
Tue Jan 13 01:39:44 EST 2015
On Mon, 12 Jan 2015 15:47:08 -0800, Rick Johnson wrote:
>> 'Some people, when confronted with a problem, think "I know, I'll use
>> regular expressions." Now they have two problems.' - Jamie Zawinski.
>
> I wonder if Jamie's conclusions are a result of careful study, or
> merely, an attempt to resolve his own cognitive dissonance?
Zawinski is one of the pantheon of geek demi-gods, with Linus, Larry,
Guido, RMS, and a few others. (Just don't ask me to rank them. I'm not
qualified.) His comment isn't based on a failure to grok regular
expressions, but on an understanding that many people use regular
expressions inappropriately.
Here is more on the context of the famous quote:
http://regex.info/blog/2006-09-15/247
(By the way, the quote actually wasn't original to JZ, he stole it from
an all but identical quote about awk.)
[...]
> For instance, in the following example, i contrive a similarly ironic
> statement to showcase the effects of such propaganda, but one that
> covers a subject matter in which laymen either: already understand, or,
> can easily attain "enough knowledge" to appreciate the humor.
>
> ############################################################ #
> Ironic Twist #
> ############################################################ # Some
> diabetics, when confronted with hunger, think "I # # know, I'll
> eat a box of sugar cookies." -- now they have # # two problems!'
Not the best of analogies, since there are two forms of diabetes. Those
with Type 2 diabetes can best manage their illness by avoiding sugar
cookies. Those with Type 1 should keep a box of sugar cookies (well,
perhaps glucose lollies are more appropriate) on hand for emergencies.
http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Diabetes_explained?open
In any case, most people with diabetes (or at least those who are still
alive) are reasonably good at managing their illness and wouldn't make
the choice you suggest. You have missed the point that people who misuse
regexes are common in programming circles, while diabetics who eat a box
of sugar cookies instead of a meal are rare.
To take your analogy to an extreme:
Some people, when faced with a problem, say "I know, I'll cut
my arm off with a pocketknife!" Now they have two problems.
This is not insightful or useful. Except in the most specialised and
extreme circumstances, such as being trapped in the wilderness with a
boulder on your arm, nobody would consider this to be good advice. But
using regexes to validate email addresses or parse HTML? The internet is
full of people who thought that was a good idea.
[...]
> Yes, i'll admit, regexps are very cryptic, but once you grasp their
> intricacies, you appreciate the succinctness of there syntax, because,
> what makes them so powerful is not only the extents of their pattern
> matching abilities, but their conciseness.
Even Larry Wall says that regexes are too concise and cryptic:
http://perl6.org/archive/doc/design/apo/A05.html
--
Steve
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