Comments on: Source of the famous “Now you have two problems” quote http://regex.info/blog/2006-09-15/247 Not a photo blog. A personal blog with photos. Tue, 07 Feb 2012 15:03:59 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: DavidY http://regex.info/blog/2006-09-15/247#comment-44632 DavidY Fri, 25 Nov 2011 21:49:57 +0000 http://regex.info/blog/2006-09-15/247#comment-44632 I know this post is now very old, but since it pertains to the origins of a quote equating a solution to a problem, I thought you might be interested in this quote, which was quothed sometime before 1832: "The solution of every problem is another problem." -Johann Wolfgang von Goethe I know this post is now very old, but since it pertains to the origins of a quote equating a solution to a problem, I thought you might be interested in this quote, which was quothed sometime before 1832:
“The solution of every problem is another problem.” -Johann Wolfgang von Goethe

]]> By: MikeP http://regex.info/blog/2006-09-15/247#comment-38487 MikeP Wed, 17 Mar 2010 03:21:34 +0000 http://regex.info/blog/2006-09-15/247#comment-38487 I know why regular expressions are a problem. It's quite simple: It's hard to distinguish between the data and operators. It's even more difficult when you add in another layer of escaping, such as emacs or perl. For example, I'm continually wondering if a parenthesis will match literally or if it will be interpreted as a grouping operator. How many backslashes will I need to get it right? In xemacs, it's always a little confusing because sometimes you're prompted for a regular expression, and sometimes you code it in lisp. I vaguely remember using a language many years back called REXX on IBM mainframes that had an interesting instruction called 'parse' that did only a fraction of what regular expressions would do, but there seemed to be a clear idea what was a pattern you were matching. I know why regular expressions are a problem.

It’s quite simple: It’s hard to distinguish between the data and operators.

It’s even more difficult when you add in another layer of escaping, such as emacs or perl.

For example, I’m continually wondering if a parenthesis will match literally or if it will be interpreted as a grouping operator. How many backslashes will I need to get it right? In xemacs, it’s always a little confusing because sometimes you’re prompted for a regular expression, and sometimes you code it in lisp.

I vaguely remember using a language many years back called REXX on IBM mainframes that had an interesting instruction called ‘parse’ that did only a fraction of what regular expressions would do, but there seemed to be a clear idea what was a pattern you were matching.

]]> By: Peter J. Hart http://regex.info/blog/2006-09-15/247#comment-38486 Peter J. Hart Wed, 17 Mar 2010 00:04:50 +0000 http://regex.info/blog/2006-09-15/247#comment-38486 "The <center> will not hold" http://stackoverflow.com/questions/1732348/regex-match-open-tags-except-xhtml-self-contained-tags “The <center> will not hold”
http://stackoverflow.com/questions/1732348/regex-match-open-tags-except-xhtml-self-contained-tags

]]> By: Eric TF Bat http://regex.info/blog/2006-09-15/247#comment-38484 Eric TF Bat Tue, 16 Mar 2010 22:49:16 +0000 http://regex.info/blog/2006-09-15/247#comment-38484 <i>Perl regex R.I.P.</i> "My name is <a href='http://en.wikipedia.org/wiki/Ozymandias' rel="nofollow">Ozymandias</a>, King of Kings \ Look on my works, ye Mighty, and despair!" Still, it would be nice to have a friendlier way to do every single thing that Perl regexps do... Perl regex R.I.P.

“My name is Ozymandias, King of Kings \ Look on my works, ye Mighty, and despair!”

Still, it would be nice to have a friendlier way to do every single thing that Perl regexps do…

]]> By: Dr. Jochen L. Leidner http://regex.info/blog/2006-09-15/247#comment-38478 Dr. Jochen L. Leidner Tue, 16 Mar 2010 15:23:26 +0000 http://regex.info/blog/2006-09-15/247#comment-38478 There's a nicer alternative to the ugly model "use regular expressions to match text patterns and print out replacements as Perl actions": Xerox has defined a language that allows name abstraction, i.e. sub-expressions can be named for comprehension, modularity and re-use. Furthermore, their language is symmetric between input and output, i.e. extended regular expressions can be run forwards and backwards (which means, if you specify a converter, you get the back converter for free). http://www.cis.upenn.edu/~cis639/docs/xfst.html http://www.stanford.edu/~laurik/fsmbook/home.html (e.g. http://www.stanford.edu/~laurik/fsmbook/examples/NumbersToNumerals.html shows a converter between English numberals: 15 -> "fifteen" or back "two hundred" -> 200) Perl regex R.I.P. <span class='jfriedl'>There are lots of languages and systems that all sort of do the same thing, and Perl was certainly not the first nor the best, but whatever gave it its staying power for the last 20 years will not vanish overnight. Given that the language you cite has been around for seven years and had no apparent impact, your "R.I.P." comment seems a touch comical. Still, I'm all for anything useful, so if it is, let's hope it gets some traction. —Jeffrey</span> There’s a nicer alternative to the ugly model “use regular expressions to match text patterns and print out replacements as Perl actions”: Xerox has defined a language that allows name abstraction, i.e. sub-expressions can be named for comprehension, modularity and re-use.
Furthermore, their language is symmetric between input and output, i.e. extended regular expressions can be run forwards and backwards (which means, if you specify a converter, you get the back converter for free).

http://www.cis.upenn.edu/~cis639/docs/xfst.html
http://www.stanford.edu/~laurik/fsmbook/home.html
(e.g. http://www.stanford.edu/~laurik/fsmbook/examples/NumbersToNumerals.html shows a converter between English numberals: 15 -> “fifteen” or back “two hundred” -> 200)

Perl regex R.I.P.

There are lots of languages and systems that all sort of do the same thing, and Perl was certainly not the first nor the best, but whatever gave it its staying power for the last 20 years will not vanish overnight. Given that the language you cite has been around for seven years and had no apparent impact, your “R.I.P.” comment seems a touch comical. Still, I’m all for anything useful, so if it is, let’s hope it gets some traction. —Jeffrey

]]> By: Fredrik http://regex.info/blog/2006-09-15/247#comment-18969 Fredrik Sat, 26 Jul 2008 12:39:18 +0000 http://regex.info/blog/2006-09-15/247#comment-18969 And for the record, I can confirm that I got the quotation from that thread. As we all know, "All good quotes come from jwz, or are slightly paraphrased versions of something he's said." (use google if you want the source of *that* quotation ;-) As for the mistaken attribution, it's just a silly mistake. But it has been fun to see how it's spread over the net over the years. And for the record, I can confirm that I got the quotation from that thread. As we all know, “All good quotes come from jwz, or are slightly paraphrased versions of something he’s said.” (use google if you want the source of *that* quotation ;-)

As for the mistaken attribution, it’s just a silly mistake. But it has been fun to see how it’s spread over the net over the years.

]]> By: Leigh L. Klotz, Jr. http://regex.info/blog/2006-09-15/247#comment-18269 Leigh L. Klotz, Jr. Fri, 06 Jun 2008 18:22:40 +0000 http://regex.info/blog/2006-09-15/247#comment-18269 OK, I think I've written more PostScript by hand than Jamie, so I assume he thinks I'm not reading this. Back in the old days, I designed a system that used incredible amounts of PostScript. One thing that made it easier for us was a C-like syntax to PS compiler, done by a fellow at the Turning Institute. We licensed it and used it heavily, and I extended it a bit to be able to handle uneven stack-armed IF, and added varieties of inheritance. The project was called <a href="http://compilers.iecc.com/comparch/article/93-01-152" rel="nofollow">PdB</a> and eventually it folded, and the author left and went to First Person Software, where he wrote a very similar language syntax for something called Oak, and it compiled to bytecodes instead of PostScript. Oak got renamed Java. So there. And yes, we did have two problems... OK, I think I’ve written more PostScript by hand than Jamie, so I assume he thinks I’m not reading this. Back in the old days, I designed a system that used incredible amounts of PostScript. One thing that made it easier for us was a C-like syntax to PS compiler, done by a fellow at the Turning Institute. We licensed it and used it heavily, and I extended it a bit to be able to handle uneven stack-armed IF, and added varieties of inheritance. The project was called
PdB and eventually it folded, and the author left and went to First Person Software, where he wrote a very similar language syntax for something called Oak, and it compiled to bytecodes instead of PostScript. Oak got renamed Java.

So there.

And yes, we did have two problems…

]]> By: Kragen Javier Sitaker http://regex.info/blog/2006-09-15/247#comment-17469 Kragen Javier Sitaker Tue, 13 May 2008 20:37:03 +0000 http://regex.info/blog/2006-09-15/247#comment-17469 Maybe the people who are claiming PostScript can be readable can post links to their readable PostScript? I agree that most PostScript you run across is less readable than it could be, and I admit I've probably written less than a thousand lines of PostScript in my life, but even the stuff in the Blue Book doesn't seem all that readable to me, compared to C or Python or elisp or, yes, even Perl. The postfix syntax (what is this block for again? is this a loop or a conditional or what? let me scan down to the end of the block --- oh, there's another block there, what's after that? Oh, ifelse, okay, where was I again?) and the point-free style (how many things does this function <code>foo</code> want on the stack? Well, apparently one less than this <code>bar</code> that it calls; where is <code>bar</code> again?), the pervasive use of higher-order programming both because it's easy and because the built-in control features are a little lame (where was that function defined again? grep can't find it...), and certain "noisy" idioms like explicit manipulation of symbol tables in order to get named local variables and fixed-size aggregate data structures... it's all kind of a mess. However, it does have some big readability <i>advantages</i> over, say, C, at least sometimes. The graphics drawing API is to die for; as long as you don't care about the error handling, it's ideal for defining embedded DSLs, precisely because of its point-free higher-order nature; it has built-in arrays and dicts (even if they are fixed-size); and so on. But these are mostly a help to readability in the large, not in the small. Anyway, this is already too long for an off-topic comment, so I'll stop. <span class='jfriedl'>I've written full-fledged applications in PostScript – it can be done – but it's important to remember that PostScript has been designed for machine-generated scripts. A human does not normally code in PostScript directly, but rather, they write a program in another language that produces PostScript to do what they want. (I realized this <i>after</i> having written said applications :-)) —Jeffrey</span> Maybe the people who are claiming PostScript can be readable can post links to their readable PostScript? I agree that most PostScript you run across is less readable than it could be, and I admit I’ve probably written less than a thousand lines of PostScript in my life, but even the stuff in the Blue Book doesn’t seem all that readable to me, compared to C or Python or elisp or, yes, even Perl. The postfix syntax (what is this block for again? is this a loop or a conditional or what? let me scan down to the end of the block — oh, there’s another block there, what’s after that? Oh, ifelse, okay, where was I again?) and the point-free style (how many things does this function foo want on the stack? Well, apparently one less than this bar that it calls; where is bar again?), the pervasive use of higher-order programming both because it’s easy and because the built-in control features are a little lame (where was that function defined again? grep can’t find it…), and certain “noisy” idioms like explicit manipulation of symbol tables in order to get named local variables and fixed-size aggregate data structures… it’s all kind of a mess.

However, it does have some big readability advantages over, say, C, at least sometimes. The graphics drawing API is to die for; as long as you don’t care about the error handling, it’s ideal for defining embedded DSLs, precisely because of its point-free higher-order nature; it has built-in arrays and dicts (even if they are fixed-size); and so on. But these are mostly a help to readability in the large, not in the small.

Anyway, this is already too long for an off-topic comment, so I’ll stop.

I’ve written full-fledged applications in PostScript – it can be done – but it’s important to remember that PostScript has been designed for machine-generated scripts. A human does not normally code in PostScript directly, but rather, they write a program in another language that produces PostScript to do what they want. (I realized this after having written said applications :-) ) —Jeffrey

]]> By: Andy http://regex.info/blog/2006-09-15/247#comment-13604 Andy Wed, 23 Jan 2008 08:36:01 +0000 http://regex.info/blog/2006-09-15/247#comment-13604 Following Yakugo's lead... “Give a man a regular expression and he’ll match a string… teach him to make his own regular expressions and you’ve got a man with problems.” –me_da_clever_one "Give a man a regular expression and he'll match a string... but by teaching him how to create them, you've given him enough rope to hang himself" - Andy Hood Following Yakugo’s lead…

“Give a man a regular expression and he’ll match a string…
teach him to make his own regular expressions and you’ve got a man with problems.”
–me_da_clever_one

“Give a man a regular expression and he’ll match a string… but by teaching him how to create them, you’ve given him enough rope to hang himself” – Andy Hood

]]> By: Marius Andersen http://regex.info/blog/2006-09-15/247#comment-11005 Marius Andersen Sat, 03 Nov 2007 22:08:39 +0000 http://regex.info/blog/2006-09-15/247#comment-11005 BTW, a preview button would have been nice. BTW, a preview button would have been nice.

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