Most unusable technology award (my nomination - regular expressions)
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Every now and then I need to solve a problem for which regular expressions looks like it is the "perfect" answer. Today that happens to be validating and extracting UK postal codes from addresses. BUT Every time I try to use regular expressions I find that no-one (especially me) has a clue how to use them and that all "posted" solutions can be demonstrated as flawed and therefore dangerous to use. The sheer complexity of the expressions makes them virtually impossible to read and therefore understand. I post the wikipedia solution to demonstrate my case (GIR 0AA)|(((A[BL]|B[ABDHLNRSTX]?|C[ABFHMORTVW]|D[ADEGHLNTY]|E[HNX]?|F[KY]|G[LUY]?|H[ADGPRSUX]|I[GMPV]|JE|K [ATWY]|L[ADELNSU]?|M[EKL]?|N[EGNPRW]?|O[LX]|P[AEHLOR]|R[GHM]|S[AEGKLMNOPRSTY]?|T[ADFNQRSW]|UB|W[ADFNRSV] |YO|ZE)[1-9]?[0-9]|((E|N|NW|SE|SW|W)1|EC[1-4]|WC[12])[A-HJKMNPR-Y]|(SW|W)([2-9]|[1-9][0-9])|EC[1-9] [0-9]) [0-9][ABD-HJLNP-UW-Z]{2}) Can anyone think of a less usable technology?
www.it-workplace.com
"If a man speaks in a forest where there is no woman to hear him, is he still wrong?"Alternate nomination: XSL
-- What's a signature?
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Every now and then I need to solve a problem for which regular expressions looks like it is the "perfect" answer. Today that happens to be validating and extracting UK postal codes from addresses. BUT Every time I try to use regular expressions I find that no-one (especially me) has a clue how to use them and that all "posted" solutions can be demonstrated as flawed and therefore dangerous to use. The sheer complexity of the expressions makes them virtually impossible to read and therefore understand. I post the wikipedia solution to demonstrate my case (GIR 0AA)|(((A[BL]|B[ABDHLNRSTX]?|C[ABFHMORTVW]|D[ADEGHLNTY]|E[HNX]?|F[KY]|G[LUY]?|H[ADGPRSUX]|I[GMPV]|JE|K [ATWY]|L[ADELNSU]?|M[EKL]?|N[EGNPRW]?|O[LX]|P[AEHLOR]|R[GHM]|S[AEGKLMNOPRSTY]?|T[ADFNQRSW]|UB|W[ADFNRSV] |YO|ZE)[1-9]?[0-9]|((E|N|NW|SE|SW|W)1|EC[1-4]|WC[12])[A-HJKMNPR-Y]|(SW|W)([2-9]|[1-9][0-9])|EC[1-9] [0-9]) [0-9][ABD-HJLNP-UW-Z]{2}) Can anyone think of a less usable technology?
www.it-workplace.com
"If a man speaks in a forest where there is no woman to hear him, is he still wrong?" -
Every now and then I need to solve a problem for which regular expressions looks like it is the "perfect" answer. Today that happens to be validating and extracting UK postal codes from addresses. BUT Every time I try to use regular expressions I find that no-one (especially me) has a clue how to use them and that all "posted" solutions can be demonstrated as flawed and therefore dangerous to use. The sheer complexity of the expressions makes them virtually impossible to read and therefore understand. I post the wikipedia solution to demonstrate my case (GIR 0AA)|(((A[BL]|B[ABDHLNRSTX]?|C[ABFHMORTVW]|D[ADEGHLNTY]|E[HNX]?|F[KY]|G[LUY]?|H[ADGPRSUX]|I[GMPV]|JE|K [ATWY]|L[ADELNSU]?|M[EKL]?|N[EGNPRW]?|O[LX]|P[AEHLOR]|R[GHM]|S[AEGKLMNOPRSTY]?|T[ADFNQRSW]|UB|W[ADFNRSV] |YO|ZE)[1-9]?[0-9]|((E|N|NW|SE|SW|W)1|EC[1-4]|WC[12])[A-HJKMNPR-Y]|(SW|W)([2-9]|[1-9][0-9])|EC[1-9] [0-9]) [0-9][ABD-HJLNP-UW-Z]{2}) Can anyone think of a less usable technology?
www.it-workplace.com
"If a man speaks in a forest where there is no woman to hear him, is he still wrong?"I think you are being a touch harsh on regular expressions. In this case it is the complexity of the postcode system that is causing the complexity of the regular expression not the other way round. Compare it to the regular expression for US zip codes (apologies if this is not entirely correct - this was grabbed from a quick google):
^(\d{5})(-\d{4})?$
The problem is that here in the UK we use a complicated postcode system that is difficult to validate via regular expressions, but that is probably easier to read by the human eye. Plus, I would add that you have managed to validate the string in a single (albeit a very long one) line. That is a plus in my book. You could also use (again from wikipedia):
[A-Z]{1,2}[0-9R][0-9A-Z]? [0-9][ABD-HJLNP-UW-Z]{2}
as a simpler more readable alternative, but which will allow some non-existent codes that do fit the normal pattern.
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Nearly, but doesn't cover the case where the user has not entered the space (i.e. 'LS1 9EL' vs 'LS19EL'). We also have some other occasional but common variations such as 'LS1_9EL' that we can try to parse for. My understanding is also that whilst this expression will validate the general format of the postcode there are specific exceptions that it does not cover. Unfortunately the task is not one of validating data at point of entry but matching data that has not been properly validated in the first place (>5m records), so refering to a web service such as the BING api is ruled out for performance reasons.
www.it-workplace.com
"If a man speaks in a forest where there is no woman to hear him, is he still wrong?"Forcing the space is trivial - every postcode ends SPACE NUMERIC ALPHA ALPHA so if there's no space just add it. The problem only comes in if you need to deal with partial entries i.e. is B11 supposed to be B1 1?? or B11 ??? If you need to properly validate as opposed to just ensuring the format is correct you will need to perform a lookup against the likes of PAF so validating at point of entry and also performing batch validation on existing data is really the best option.
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Every now and then I need to solve a problem for which regular expressions looks like it is the "perfect" answer. Today that happens to be validating and extracting UK postal codes from addresses. BUT Every time I try to use regular expressions I find that no-one (especially me) has a clue how to use them and that all "posted" solutions can be demonstrated as flawed and therefore dangerous to use. The sheer complexity of the expressions makes them virtually impossible to read and therefore understand. I post the wikipedia solution to demonstrate my case (GIR 0AA)|(((A[BL]|B[ABDHLNRSTX]?|C[ABFHMORTVW]|D[ADEGHLNTY]|E[HNX]?|F[KY]|G[LUY]?|H[ADGPRSUX]|I[GMPV]|JE|K [ATWY]|L[ADELNSU]?|M[EKL]?|N[EGNPRW]?|O[LX]|P[AEHLOR]|R[GHM]|S[AEGKLMNOPRSTY]?|T[ADFNQRSW]|UB|W[ADFNRSV] |YO|ZE)[1-9]?[0-9]|((E|N|NW|SE|SW|W)1|EC[1-4]|WC[12])[A-HJKMNPR-Y]|(SW|W)([2-9]|[1-9][0-9])|EC[1-9] [0-9]) [0-9][ABD-HJLNP-UW-Z]{2}) Can anyone think of a less usable technology?
www.it-workplace.com
"If a man speaks in a forest where there is no woman to hear him, is he still wrong?"Maybe my RE-fu is strong today, but this seems fairly easy to follow - just a matter of breaking it down: GIR special case (permitted letter groups starting with each letter of alphabet) number (and additional following number) London variants (E, EC, etc) etc... However, I personally would have split the London codings away from the rest, as this RE permits say "YO1EC4 1XY" which is nonsense.
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Every now and then I need to solve a problem for which regular expressions looks like it is the "perfect" answer. Today that happens to be validating and extracting UK postal codes from addresses. BUT Every time I try to use regular expressions I find that no-one (especially me) has a clue how to use them and that all "posted" solutions can be demonstrated as flawed and therefore dangerous to use. The sheer complexity of the expressions makes them virtually impossible to read and therefore understand. I post the wikipedia solution to demonstrate my case (GIR 0AA)|(((A[BL]|B[ABDHLNRSTX]?|C[ABFHMORTVW]|D[ADEGHLNTY]|E[HNX]?|F[KY]|G[LUY]?|H[ADGPRSUX]|I[GMPV]|JE|K [ATWY]|L[ADELNSU]?|M[EKL]?|N[EGNPRW]?|O[LX]|P[AEHLOR]|R[GHM]|S[AEGKLMNOPRSTY]?|T[ADFNQRSW]|UB|W[ADFNRSV] |YO|ZE)[1-9]?[0-9]|((E|N|NW|SE|SW|W)1|EC[1-4]|WC[12])[A-HJKMNPR-Y]|(SW|W)([2-9]|[1-9][0-9])|EC[1-9] [0-9]) [0-9][ABD-HJLNP-UW-Z]{2}) Can anyone think of a less usable technology?
www.it-workplace.com
"If a man speaks in a forest where there is no woman to hear him, is he still wrong?"I nominate windows command prompt..... but i dont agree with regular expressions being unusable. Its been years since they were developed and today also they perform their basic task very well for which they were formed - to save space in code. Always i use them i think of all the if-else conditions which would have haunted me in the absence of regular expressions
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I first saw that line was used in the end-of-mag article for "Language" magazine (an early issue). The article showed how to write a program that called a function that returned the cube of the numbers 1 through 10, doing so in a large number of languages for comparison. Interestingly, the shortest version was one of the Unix shells. I believe the magazine to have gone away to wherever they go to.
"The difference between genius and stupidity is that genius has its limits." - Albert Einstein
"As far as we know, our computer has never had an undetected error." - Weisert
"If you are searching for perfection in others, then you seek disappointment. If you are seek perfection in yourself, then you will find failure." - Balboos HaGadol Mar 2010
I recall reading that line at least some 10 years ago, and I wondered where it came from. Apparently it's much older: at least from 1964
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Nearly, but doesn't cover the case where the user has not entered the space (i.e. 'LS1 9EL' vs 'LS19EL'). We also have some other occasional but common variations such as 'LS1_9EL' that we can try to parse for. My understanding is also that whilst this expression will validate the general format of the postcode there are specific exceptions that it does not cover. Unfortunately the task is not one of validating data at point of entry but matching data that has not been properly validated in the first place (>5m records), so refering to a web service such as the BING api is ruled out for performance reasons.
www.it-workplace.com
"If a man speaks in a forest where there is no woman to hear him, is he still wrong?"If variable formats are that much of an issue, why not just put it through a preprocessor that standardizes the format (in your example, to weed out superfluous spaces and '_'). Sounds inpractical to me to add formating issues to the RE.
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Alternate nomination: XSL
-- What's a signature?
Yes, I've considered that too - and most of the XML-related stuff. But at least you have the option to make it halfway readable. It can be a real pain though if you have to delve in to other people's code and the original programmer took no care of naming conventions and formatting...
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Every now and then I need to solve a problem for which regular expressions looks like it is the "perfect" answer. Today that happens to be validating and extracting UK postal codes from addresses. BUT Every time I try to use regular expressions I find that no-one (especially me) has a clue how to use them and that all "posted" solutions can be demonstrated as flawed and therefore dangerous to use. The sheer complexity of the expressions makes them virtually impossible to read and therefore understand. I post the wikipedia solution to demonstrate my case (GIR 0AA)|(((A[BL]|B[ABDHLNRSTX]?|C[ABFHMORTVW]|D[ADEGHLNTY]|E[HNX]?|F[KY]|G[LUY]?|H[ADGPRSUX]|I[GMPV]|JE|K [ATWY]|L[ADELNSU]?|M[EKL]?|N[EGNPRW]?|O[LX]|P[AEHLOR]|R[GHM]|S[AEGKLMNOPRSTY]?|T[ADFNQRSW]|UB|W[ADFNRSV] |YO|ZE)[1-9]?[0-9]|((E|N|NW|SE|SW|W)1|EC[1-4]|WC[12])[A-HJKMNPR-Y]|(SW|W)([2-9]|[1-9][0-9])|EC[1-9] [0-9]) [0-9][ABD-HJLNP-UW-Z]{2}) Can anyone think of a less usable technology?
www.it-workplace.com
"If a man speaks in a forest where there is no woman to hear him, is he still wrong?"I get where you are coming from but you are only saying it because you haven't learned regex. Its a bit like saying I dont think Spanish is a usable language because I haven't learned it :) I have casually learned it over the last few years and I couldn't live without it these days. First off you need a tool (I use Expresso, linked elsewhere in this thread). This will parse your regex into a tree that helps you understand it. It also lets you store test cases so you can quickly check what is valid and what isn't. If you so choose you can format your regex on multiple lines and and # comments explaining what each line does. That is a big regex that you have posted but its because it is trying to do something complicated. You can make a regex to recognise potential postcodes which would be a lot simpler and it would just recognise a pattern of letters+numbers but that one takes into account every known postcode and only allows valid postcodes. It depends what you're trying to achieve. Also there are sites that share regex and people can vote on them. Anyway i'm obviously a fan of regex :) Here is my vote for most unusable tech: The Brainfuck programming language http://en.wikipedia.org/wiki/Brainfuck[^]
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I get where you are coming from but you are only saying it because you haven't learned regex. Its a bit like saying I dont think Spanish is a usable language because I haven't learned it :) I have casually learned it over the last few years and I couldn't live without it these days. First off you need a tool (I use Expresso, linked elsewhere in this thread). This will parse your regex into a tree that helps you understand it. It also lets you store test cases so you can quickly check what is valid and what isn't. If you so choose you can format your regex on multiple lines and and # comments explaining what each line does. That is a big regex that you have posted but its because it is trying to do something complicated. You can make a regex to recognise potential postcodes which would be a lot simpler and it would just recognise a pattern of letters+numbers but that one takes into account every known postcode and only allows valid postcodes. It depends what you're trying to achieve. Also there are sites that share regex and people can vote on them. Anyway i'm obviously a fan of regex :) Here is my vote for most unusable tech: The Brainfuck programming language http://en.wikipedia.org/wiki/Brainfuck[^]
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Every now and then I need to solve a problem for which regular expressions looks like it is the "perfect" answer. Today that happens to be validating and extracting UK postal codes from addresses. BUT Every time I try to use regular expressions I find that no-one (especially me) has a clue how to use them and that all "posted" solutions can be demonstrated as flawed and therefore dangerous to use. The sheer complexity of the expressions makes them virtually impossible to read and therefore understand. I post the wikipedia solution to demonstrate my case (GIR 0AA)|(((A[BL]|B[ABDHLNRSTX]?|C[ABFHMORTVW]|D[ADEGHLNTY]|E[HNX]?|F[KY]|G[LUY]?|H[ADGPRSUX]|I[GMPV]|JE|K [ATWY]|L[ADELNSU]?|M[EKL]?|N[EGNPRW]?|O[LX]|P[AEHLOR]|R[GHM]|S[AEGKLMNOPRSTY]?|T[ADFNQRSW]|UB|W[ADFNRSV] |YO|ZE)[1-9]?[0-9]|((E|N|NW|SE|SW|W)1|EC[1-4]|WC[12])[A-HJKMNPR-Y]|(SW|W)([2-9]|[1-9][0-9])|EC[1-9] [0-9]) [0-9][ABD-HJLNP-UW-Z]{2}) Can anyone think of a less usable technology?
www.it-workplace.com
"If a man speaks in a forest where there is no woman to hear him, is he still wrong?"Reminds me very much of some of the formulas in the Excel Sheets we're supposed to fill in for certain reports - only those are much longer! It can get pretty awful to find the problem when they reference not only other sheets, but sheets in other tables that are supposed to be in the same folder (but weren't included in the copy you were sent) :doh: On the plus side, they are slightly more verbose. Not that it helps ...
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Yes, I've considered that too - and most of the XML-related stuff. But at least you have the option to make it halfway readable. It can be a real pain though if you have to delve in to other people's code and the original programmer took no care of naming conventions and formatting...
Quite true, though its possible to make a regex readable (at least in PERL) by using the "ignore whitespace" option which allows you both to break it over several lines and to embed comments see this article[^]
-- What's a signature?
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Every now and then I need to solve a problem for which regular expressions looks like it is the "perfect" answer. Today that happens to be validating and extracting UK postal codes from addresses. BUT Every time I try to use regular expressions I find that no-one (especially me) has a clue how to use them and that all "posted" solutions can be demonstrated as flawed and therefore dangerous to use. The sheer complexity of the expressions makes them virtually impossible to read and therefore understand. I post the wikipedia solution to demonstrate my case (GIR 0AA)|(((A[BL]|B[ABDHLNRSTX]?|C[ABFHMORTVW]|D[ADEGHLNTY]|E[HNX]?|F[KY]|G[LUY]?|H[ADGPRSUX]|I[GMPV]|JE|K [ATWY]|L[ADELNSU]?|M[EKL]?|N[EGNPRW]?|O[LX]|P[AEHLOR]|R[GHM]|S[AEGKLMNOPRSTY]?|T[ADFNQRSW]|UB|W[ADFNRSV] |YO|ZE)[1-9]?[0-9]|((E|N|NW|SE|SW|W)1|EC[1-4]|WC[12])[A-HJKMNPR-Y]|(SW|W)([2-9]|[1-9][0-9])|EC[1-9] [0-9]) [0-9][ABD-HJLNP-UW-Z]{2}) Can anyone think of a less usable technology?
www.it-workplace.com
"If a man speaks in a forest where there is no woman to hear him, is he still wrong?"You're not supposed to understand it, just go to a "regular expression website", read the description and the comments and copy/paste what you need. Never try to debug it yourself, just complain to the person who wrote it. :laugh: There's a community of "special people" for everything.
Giraffes are not real.
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Manfred R. Bihy wrote:
If the only tool you've got is a hammer, every problem looks like a nail!
I like that. :thumbsup:
Just along for the ride. "the meat from that butcher is just the dogs danglies, absolutely amazing cuts of beef." - DaveAuld (2011)
"No, that is just the earthly manifestation of the Great God Retardon." - Nagy Vilmos (2011) "It is the celestial scrotum of good luck!" - Nagy Vilmos (2011)Slacker007 wrote:
Manfred R. Bihy wrote:
If the only tool you've got is a hammer, every problem looks like a nail!
I like that. :thumbsup:
I believe it was a quote from Jesus, in an early draft of the Bible. It was discarded the final edit, along with many other gems, like "Ow, my #$%&ing thumb!"
I wanna be a eunuchs developer! Pass me a bread knife!
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Nearly, but doesn't cover the case where the user has not entered the space (i.e. 'LS1 9EL' vs 'LS19EL'). We also have some other occasional but common variations such as 'LS1_9EL' that we can try to parse for. My understanding is also that whilst this expression will validate the general format of the postcode there are specific exceptions that it does not cover. Unfortunately the task is not one of validating data at point of entry but matching data that has not been properly validated in the first place (>5m records), so refering to a web service such as the BING api is ruled out for performance reasons.
www.it-workplace.com
"If a man speaks in a forest where there is no woman to hear him, is he still wrong?"Then test for basic, then retest the exceptions. Beats the Hell out of a 300-character regex.
I wanna be a eunuchs developer! Pass me a bread knife!
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Every now and then I need to solve a problem for which regular expressions looks like it is the "perfect" answer. Today that happens to be validating and extracting UK postal codes from addresses. BUT Every time I try to use regular expressions I find that no-one (especially me) has a clue how to use them and that all "posted" solutions can be demonstrated as flawed and therefore dangerous to use. The sheer complexity of the expressions makes them virtually impossible to read and therefore understand. I post the wikipedia solution to demonstrate my case (GIR 0AA)|(((A[BL]|B[ABDHLNRSTX]?|C[ABFHMORTVW]|D[ADEGHLNTY]|E[HNX]?|F[KY]|G[LUY]?|H[ADGPRSUX]|I[GMPV]|JE|K [ATWY]|L[ADELNSU]?|M[EKL]?|N[EGNPRW]?|O[LX]|P[AEHLOR]|R[GHM]|S[AEGKLMNOPRSTY]?|T[ADFNQRSW]|UB|W[ADFNRSV] |YO|ZE)[1-9]?[0-9]|((E|N|NW|SE|SW|W)1|EC[1-4]|WC[12])[A-HJKMNPR-Y]|(SW|W)([2-9]|[1-9][0-9])|EC[1-9] [0-9]) [0-9][ABD-HJLNP-UW-Z]{2}) Can anyone think of a less usable technology?
www.it-workplace.com
"If a man speaks in a forest where there is no woman to hear him, is he still wrong?"Can I nominate Lotus Notes? "I am rarely happier than when spending entire day programming my computer to perform automatically a task that it would otherwise take me a good ten seconds to do by hand." - Douglas Adams
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Every now and then I need to solve a problem for which regular expressions looks like it is the "perfect" answer. Today that happens to be validating and extracting UK postal codes from addresses. BUT Every time I try to use regular expressions I find that no-one (especially me) has a clue how to use them and that all "posted" solutions can be demonstrated as flawed and therefore dangerous to use. The sheer complexity of the expressions makes them virtually impossible to read and therefore understand. I post the wikipedia solution to demonstrate my case (GIR 0AA)|(((A[BL]|B[ABDHLNRSTX]?|C[ABFHMORTVW]|D[ADEGHLNTY]|E[HNX]?|F[KY]|G[LUY]?|H[ADGPRSUX]|I[GMPV]|JE|K [ATWY]|L[ADELNSU]?|M[EKL]?|N[EGNPRW]?|O[LX]|P[AEHLOR]|R[GHM]|S[AEGKLMNOPRSTY]?|T[ADFNQRSW]|UB|W[ADFNRSV] |YO|ZE)[1-9]?[0-9]|((E|N|NW|SE|SW|W)1|EC[1-4]|WC[12])[A-HJKMNPR-Y]|(SW|W)([2-9]|[1-9][0-9])|EC[1-9] [0-9]) [0-9][ABD-HJLNP-UW-Z]{2}) Can anyone think of a less usable technology?
www.it-workplace.com
"If a man speaks in a forest where there is no woman to hear him, is he still wrong?"I would like to nominate my iPhone 3G for the award. Via iOS updates, Apple managed to turn my phone into a completely useless brick. At times, it could take up to 10 seconds for one of the little "folders" to open up after tapping on it. And that was just one of the features that failed to perform. Voicemail problems, WiFi problems, frequent crashing, etc. Fortunately, my wife dropped the phone into the swimming pool and now I am a very much happier Windows Phone user.
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That would be my approach too, and I spent a long time working with the Postal Address File in the UK. To attempt to write one regex for the whole thing leads to monstrosities like the one demonstrated. That said, I too dislike R.E.'s. They seem to me to be easy and quick to write, but tough to read. Good in an editor's search box, or tool like grep, bad in code that must be viewed by other developers. I don't object to regular languages, just the form of reg ex's that has come into use over the years. There a few examples of regular languages better done, notably in the MGrammar parser technology Microsoft tech previewed a while ago (which I guess has, unfortunately, floundered in their dev labs as they seem to have gone silent).
I have to say, my tendency would be to have a list of the known postal codes and put that into an array. Then use a string compare to just look for matches to all known postal codes first. Then after that start doing evals to look for things that fit the known formats but aren't on the known list, if possible, presuming each entry is a separate line or item in an array, only putting the lines or items that haven't already matched into a separate array and checking those. Not sure if my solution is more or less complicated. It's probably colored by my experience as a LAMP dev though.
CaptJosh There are only 10 kinds of people in the world; those who understand binary and those who don't.
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Can I nominate Lotus Notes? "I am rarely happier than when spending entire day programming my computer to perform automatically a task that it would otherwise take me a good ten seconds to do by hand." - Douglas Adams