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posted by janrinok on Wednesday March 27, @08:12PM   Printer-friendly
from the I-didn't-know-that-... dept.

https://buttondown.email/hillelwayne/archive/why-do-regexes-use-and-as-line-anchors/

Last week I fell into a bit of a rabbit hole: why do regular expressions use $ and ^ as line anchors?1

This talk brings up that they first appeared in Ken Thompson's port of the QED text editor. In his manual he writes: b) "^" is a regular expression which matches character at the beginning of a line.

c) "$" is a regular expression which matches character before the character (usually at the end of a line)

QED was the precursor to ed, which was instrumental in popularizing regexes, so a lot of its design choices stuck.

Okay, but then why did Ken Thompson choose those characters?


Original Submission

 
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  • (Score: 4, Insightful) by krishnoid on Wednesday March 27, @11:56PM (10 children)

    by krishnoid (1156) on Wednesday March 27, @11:56PM (#1350600)

    How about a few CSS files, maybe even manually selectable -- phone, tablet, desktop? Then we don't need Javascript, and CSS is really powerful as it is.

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  • (Score: 5, Touché) by janrinok on Wednesday March 27, @11:59PM (3 children)

    by janrinok (52) Subscriber Badge on Wednesday March 27, @11:59PM (#1350601) Journal

    Are you volunteering for a job? :D

    --
    I am not interested in knowing who people are or where they live. My interest starts and stops at our servers.
    • (Score: 2, Interesting) by shrewdsheep on Thursday March 28, @10:11AM (2 children)

      by shrewdsheep (5215) on Thursday March 28, @10:11AM (#1350654)

      Why the quip? The thread earlier was lining up against any change to the website. In view of the future of the site, I strongly support CSS optimizations and the use of limited javascript to improve usability. The old style can and should always be retained as a tribute to the legacy of the site. The user base has to be broadened for long term survival of SN and I believe that appearance and usability is a good part of it when it comes to attract new readership.

      • (Score: 4, Informative) by janrinok on Thursday March 28, @10:54AM (1 child)

        by janrinok (52) Subscriber Badge on Thursday March 28, @10:54AM (#1350657) Journal

        It was merely asking who would be doing this task? To have selectable CSS pages will require significant Perl code changes and new fields adding to the database so that the user's choice is remembered between log-ins. The displays are created by templates which might have to be changed to cope with different CSS. It is not my area.

        No offence was intended. I did include a grin!

        --
        I am not interested in knowing who people are or where they live. My interest starts and stops at our servers.
        • (Score: 2, Interesting) by Anonymous Coward on Thursday March 28, @04:42PM

          by Anonymous Coward on Thursday March 28, @04:42PM (#1350716)

          To have selectable CSS pages will require significant Perl code changes and new fields adding to the database so that the user's choice is remembered between log-ins.

          User-selectable alternate stylesheets were an original design feature of CSS but it's unfortunate that the browser support today is completely useless.

          The CSS2 specification actually says that user agents must provide an interface to change between alternate stylesheets [w3.org]. I don't know if this requirement persists in current specifications. Firefox has the choice in a hidden menu but it forgets your selection as soon as you reload the page or follow any link so it's basically unusable. Such a shame.

  • (Score: 3, Interesting) by bzipitidoo on Thursday March 28, @12:24PM (5 children)

    by bzipitidoo (4388) on Thursday March 28, @12:24PM (#1350667) Journal

    CSS is great, but should even that be necessary? Reflowing of text to fit window sizes is a core feature of plain old HTML. No more reliance on CR/LF for that. If a user is forced to scroll back and forth to view the full width, despite the site not using any JavaScript or set widths or whatever, that seems to me a problem with their environment, not the site. Note also that the browser has the final say over fonts. A site can give relative size differences; the user's system ultimately sets what size "big", "normal" and "small" are.

    A common idea is a mobile version of the site. m.soylentnews.org

    • (Score: 3, Informative) by janrinok on Thursday March 28, @12:50PM

      by janrinok (52) Subscriber Badge on Thursday March 28, @12:50PM (#1350671) Journal
      m.soylentnews.org doesn't seem to work for the moment.
      --
      I am not interested in knowing who people are or where they live. My interest starts and stops at our servers.
    • (Score: 2) by owl on Thursday March 28, @07:29PM (1 child)

      by owl (15206) on Thursday March 28, @07:29PM (#1350745)

      CSS is great, but should even that be necessary? Reflowing of text to fit window sizes is a core feature of plain old HTML. No more reliance on CR/LF for that.

      Because by far too many designers feel some hugely irrational need to control the layout to a level far more strict than "let html lay out the data based upon the viewport width".

      Note that most of these designers are those from the "publishing" environment where positioning text in this corner of a page, and a highlight image over in this other spot, in order to leave room in three other places for three ad slots, was what they were trained to do.

      I.e., they never even consider just letting the HTML lay itself out natively. They need to control where it goes, to the pixel, or they feel they have failed.

      • (Score: 2) by krishnoid on Thursday March 28, @09:21PM

        by krishnoid (1156) on Thursday March 28, @09:21PM (#1350758)

        Designers are probably trained for traditional print media, and something that describes layouts and floats using declarative and markup languages is probably going to require a GUI for them to be able to do their thing. They're not coders, after all.

    • (Score: 3, Insightful) by maxwell demon on Friday March 29, @07:39AM (1 child)

      by maxwell demon (1608) on Friday March 29, @07:39AM (#1350819) Journal

      A common idea is a mobile version of the site. m.soylentnews.org

      That's the absolute worst thing to do. If I follow a link, it should work equally well if I follow it on a desktop or on a laptop.

      --
      The Tao of math: The numbers you can count are not the real numbers.
      • (Score: 2) by maxwell demon on Friday March 29, @07:41AM

        by maxwell demon (1608) on Friday March 29, @07:41AM (#1350820) Journal

        Err, mistyped, and only noticed after submit: I of course meant desktop or phone.

        And in addition I now have to wait with posting this correction due to the unreasonable long wait time enforced by the Rehash software.

        --
        The Tao of math: The numbers you can count are not the real numbers.