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Elastic Tabstops — An End to Tabs vs. Spaces?

Posted by timothy on Mon Jul 03, 2006 02:07 PM
from the stretchy-logic dept.
Programming IT Technology
An anonymous reader writes "Along with Vi versus Emacs, the tabs versus spaces argument must rank as one of the classic holy wars among coders. Here's an attempt to solve it by making tabstops expand or shrink to fit their contents. The concept's pretty cool to use, so be sure to have a play with the demo!"
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Elastic Tabstops — An End to Tabs vs. Spaces? 50 Comments More /

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  • From Wiki (Score:5, Funny)

    by neonprimetime (528653) on Monday July 03 2006, @02:16PM (#15651732)
    Use of the term "Holy War" implies that the root of the disagreement is a clash of values, and intractible of resolution except by agreeing to disagree.

    My bible says it is morally wrong to use Vi.
    • :s/Vi/Emacs/g
    • My bible says it is morally wrong to use Vi.

      Well, of course it is. VI is Latin for 6, which is 1/3 of 666, and we know what that stands for.

      As further proof, check vi's origins. It came from Berkeley, and their BSD system has a little d[a]emon as a symbol. Spawn of Satan, QED.

    • Re:From Wiki (Score:5, Funny)

      by DesertWolf0132 (718296) on Monday July 03 2006, @02:44PM (#15651948) Homepage

      Mine says,

      "And behold sayeth the Lord, thou shalt edit thine text in Vi and Vi alone, even when thou art forced by the unclean luser to useth the operating system of unholiness. Thou shalt always keep a copy of the Holy editor on thine key of the USB lest thou shalt fall into temptation and edit thine text in the way of the unclean. Any who useth Emacs or the accursed notepad shalt be stricken from the Book of the Holy Sysadmin for all eternity. So sayeth the Lord." -1st Epistle to the Admins of Systems 1:15-16

      There it is in black and white. Vi is the way of truth and light. All others are unclean.

      • Nope, afraid not. vi is a modern-day abomination. Ed is the standard text editor. [gnu.org]
      • However, in the second book of Coders, 1:2-5, we find the following:

        2 And BOFH called a little coder unto him, and set him in the midst of them, 3 And said, Verily I say unto you, Except ye be converted, and become as this emacs user, ye shall not enter into the kingdom of unix. 4 Whosoever therefore shall humble himself as this little coder, the same is greatest in the kingdom of unix. Then were there brought unto him other little coders, that he should put his hands on them, and give them emacs: and the a

  • How we got here (Score:5, Interesting)

    by Animats (122034) on Monday July 03 2006, @02:18PM (#15651741) Homepage

    The way we got into this mess is that in early versions of UNIX, tab stops were set to 8 spaces in the TTY handler. This was not because tab stops were intended as indentation. It was because an ASR-33 teletype could tab that far in one character time. It was for optimizing output time. (Back in those days, TTY output processing had to have time delays to handle the mechanical lag in printers. "How many nulls were required after each carriage return" was an issue, and better systems kept track of the printing column position and adjusted the delay accordingly. Peripherals used to be really dumb.)

    If some reasonable indentation value like 4 or 5 had been chosen, everything would have been fine.

    • Not just mechanical output devices. I wrote a TTY driver for a Viewpoint terminal that I was driving from an 8052. That thing needed delays all over the place. (Imagine my surprise, years later, to open one up and find an 8051 sitting in there.) I actually discovered it needed delays from the UNIX side of things, because the first thing I implemented was a serial-to-serial pass through, and I had to mess w/ the various stty delay settings before I stopped losing text.

      But, yes... 80 columns goes back

  • Whether or not this solves the problem (I don't think it does), I get real nervous when source code starts being perceived as a document that lends itself to proportional fonts. Maybe I haven't been in the latest and greatest IDEs lately and am missing something here, but source code seems to scream for canonical form, and proportional font is not that.

    I think vim has a reasonable approach (do the research: shiftwidth, tabstops, softtabstop, etc.), I assume there are other approaches in emacs.

    Start talking about proportional font source code documents, and now everyone's going to want to have styles, and all the confusing garbage that is word processing. As difficult as source code and programming is, it doesn't need to be more nuanced in word processing.

    • I think that this is good, I aways thought that tabs for identation is simply a better idea just because it made simple for people to see the code the way they feel more conforable with. I don't think 'styles' is a problem, it is just the oposite, imagine if we could make a "style sheet" of some sort and apply to the code and sudenly all the code you load into your editor is styled as you liked?

      I use the command line program ident to apply my style to other people's code, sure I don't send them this way I r
      • "imagine if we could make a "style sheet" of some sort and apply to the code and sudenly all the code you load into your editor is styled as you liked?"

        Yeah, but people would still screw it up. For example:

        // K&R style -- comments on the if/else go before
        if () {
        // comments on the if clause go after the first {
        } else {
        // comments on the else go after the else {
        }

        // BSD style
        if ()
        {
        }
        else
        {
        }

        # Conway style
        if () {
        }
        # This also is a problem with BSD, but I thought I
  • Tabs have been and should continue to be what they are. If you need to format code within the 8 spaces, then use a tab. Otherwise use a space. In no other way can we get source code that looks consistant across editors and platforms. Especially in neat languages like python. Attempts to redefine tab stops are misguided. And don't even get me started on the use of proportional fonts in programming editors. Heresy.
    • Wrong. A TAB represents 1-N spaces, depending on the current column, where N is the tab setting. I've never seen a TAB interpreted as a fixed number of spaces, and I've seen a lot of output devices in the 40 or so years I've been playing with computers. TABs move the output position to the next tab stop, not some fixed number of spaces.

  • Start up his Java editor, and replace the line:

    [TAB]if (1)

    With the line:

    [TAB]if (this_sucks())[TAB]/* Always returns true */

    And watch as the tab spacing of "lalala();" two lines down gets ruined.

    He's right that mandating "tabs must be N spaces" is stupid, though. Use tabs to indent blocks of code, use spaces for aligning code that isn't in blocks, and people should be able to set whatever tab size they want without ruining anything.

    int myfunc(int arg1,
    Class arg2) /*

  • (setq-default indent-tabs-mode nil)

    Then emacs will replace tabs with spaces. In the various programming language modes, tab indents to the right location (Which you can customize somewhere else.)

    vim has a similar setting but I rather despise vim (I prefer nvi or old school vi when doing vi things.)

  • What a great social engineering trick - get 30% of Slashdot readers to locally execute untrusted code with local thought. Cracker, my hat is off to you!
  • The subject of tabs vs spaces should be clear enough to everyone.

    Let me quote the relevant standard:

    Linux kernel coding style
    [cut]
    First off, I'd suggest printing out a copy of the GNU coding standards,
    and NOT read it. Burn them, it's a great symbolic gesture.
    [cut]
                      Chapter 1: Indentation

    Tabs are 8 characters, and thus indentations are also 8 characters.
    There are heretic movements that try to make indentations 4 (or even 2!)
    characters deep, and that is akin to trying to define the value of PI to
    be 3.

    Rationale: The whole idea behind indentation is to clearly define where
    a block of control starts and ends. Especially when you've been looking
    at your screen for 20 straight hours, you'll find it a lot easier to see
    how the indentation works if you have large indentations.

    Now, some people will claim that having 8-character indentations makes
    the code move too far to the right, and makes it hard to read on a
    80-character terminal screen. The answer to that is that if you need
    more than 3 levels of indentation, you're screwed anyway, and should fix
    your program.

    In short, 8-char indents make things easier to read, and have the added
    benefit of warning you when you're nesting your functions too deep.
    Heed that warning.

    [cut]
    But even if you fail in getting emacs to do sane formatting, not
    everything is lost: use "indent".

    Now, again, GNU indent has the same brain dead settings that GNU emacs
    has, which is why you need to give it a few command line options.
    However, that's not too bad, because even the makers of GNU indent
    recognize the authority of K&R (the GNU people aren't evil, they are
    just severely misguided in this matter), so you just give indent the
    options "-kr -i8" (stands for "K&R, 8 character indents").

    "indent" has a lot of options, and especially when it comes to comment
    re-formatting you may want to take a look at the manual page. But
    remember: "indent" is not a fix for bad programming.

    Linus Torvalds.

  • Consistency is better than religion (Score:4, Insightful)

    by morrison (40043) * on Monday July 03 2006, @03:53PM (#15652358) Homepage

    For several large projects I work with where there are lots of developers, consistency of the source code is considerably more important than any particular developer's opinion on what the correct behavior of tabs and spaces are. These are projects where it is pretty much expected that there are or will at least eventually be developers that use both vi and emacs with zealotry as well a myriad of IDE environments. For at least vi and emacs, all source files utilize a local variables block that is understood by both editors in order to encourage a project-defined convention with consistent indentation:

    /*
    * Local Variables:
    * mode: C
    * tab-width: 8
    * c-basic-offset: 4
    * indent-tabs-mode: t
    * End:
    * ex: shiftwidth=4 tabstop=8
    */

    With that comment block at the very end of all source files (whether they be C, C++, Tcl, Perl, Sh, SGML, etc), we do quite well in maintaining order and minimizing the indentation dispute. For the IDE environments, it at least gives them clear documentation on how to configure their IDE indentation preferences to match in every file. Maintaining a tabwidth/tabstop of 8 ensures consistent source display in most environments, including text printing and console display, leaving projects to simply define what offset/shiftwidth level they want for indentation. It can similarly still be tweaked for the projects that seem to insist on no tabs or want to match some IDE default religion.

  • Don't mix em. (Score:3, Informative)

    by Spudley (171066) on Monday July 03 2006, @04:33PM (#15652564) Homepage Journal
    I don't mind tabs. I don't mind spaces.

    But God help you if you mix them together in the same program.

    I've met editors that put four spaces for the first indent, then a tab for the second (removing the previous four spaces in the process). It was fine when you viewed the code in that particular editor, but open the same code in another editor with different tab stops, and it became practically unreadable. If they'd stuck with just tabs or just spaces it would have been fine, but nooooo.... some bright spark had to mix 'em together. Grrrrrrr.

    (For what it's worth, the editor in question was LSE, on a VMS system. I don't know to this day whether that was the default setting or a setup made by someone at the company, but it caused a nightmare when we ported the system to Windows)

  • Uh... ok... (Score:4, Funny)

    by zizzo (86200) <fishbolt@yaho[ ]om ['o.c' in gap]> on Monday July 03 2006, @05:59PM (#15653087) Homepage
    I read the article and played his demo. I'm not excited by this at all for 2 reasons: it invents yet another model of tab spacing and it encourages use of tabs.

    Tabs just need to go away so we can get back to real debates, like CR vs. CR/LF vs. LF.

    • I want to be able to indent or unindent the opening statement for a given loop, be it int, sub, function, if, for or else, and have the entire section that it describes, including the braces, indent accordingly. Anyone know of an editor that has this?

      both vim and emacs will do this. unless i misread the question...
    • Eclipse does that.

      I don't know what the big deal is, just :set ts=4

    • Re:A standard tab length would be easier (Score:5, Insightful)

      by Jeremi (14640) on Monday July 03 2006, @02:16PM (#15651731) Homepage
      I think this is the wrong kind of solution to the problem. A standard would be easier. Just have someone say "Tabs are now officially SOME_NUMBER spaces long, so fuck you."


      You might as well tell the world "Earth's official language is now officially Esperanto, so fuck you". The effect would be about the same.

      • You might as well tell the world "Earth's official language is now officially Esperanto, so fuck you". The effect would be about the same.

        La lingvo oficiala da tero estas Esperanton, tial fiku vin!

        • I must have missed the part of the discussion where tabs/spacing became intimately interwoven into human culture and society.

          They became interwoven into the computer-programming subset of society back in the 60's and 70's, if not earlier.

          But even beside that, a lot of things are set semi-arbitrarily in the tech world. So why not the length of a tab?

          Because the proposal isn't to define a new standard, it's to re-define a very well-entrenched (if crappy) existing standard. All 60 million people who are alrea

          • How can you tell whether nobody will use a new standard if it is significantly better than the old one? If you admit the old standard is crappy, why not even try for the better? Considering how tabs tend to break across platforms or even across applications, it already seems like everyone is doing what he wants anyway. Doing or not doing things because "that's the way it used to be and we don't want change because change is hard" just doesn't make sense, especially considering the fact that we're talking ab
    • Actually, it is attempts to do that which have created the current confusion. Some were obviously too long, some obviously too short, and the end result is tabs which aren't useful.

      I actually like this idea, because it actually you from using this seemingly-simple but in actuality horribly complicated idea that tab = x*space. Instead they have an actually simple idea: Each tab is a seperate column of text. Line up items in the same column with each other. (Of course, how simple this is in practice is yet to be deterimined, but it seems simpler to me.)

      This idea is actually about seperateing sementic and content info. Programmers use tabs (those who do) to convey sementic info. If we can make the program understand that, then we can offer more flexiblity to the user on how to present the information.

    • I want to be able to indent or unindent the opening statement for a given loop, be it int, sub, function, if, for or else, and have the entire section that it describes, including the braces, indent accordingly.

      In Vim: Press shift+v to highlight the current line, go to the opening brace, press % to go to the closing brace (highlighting the whole block in turn), then press = to auto-indent.

      In command mode, == auto-indents the current line, << and >> indent to right and left respectively.

      Back to t

    • Re:A standard tab length would be easier (Score:5, Informative)

      by GroeFaZ (850443) on Monday July 03 2006, @02:34PM (#15651885)
      Anyone know of an editor that has this?

      If you want that from an IDE, eclipse does that, and pretty robustly at that. I wouldn't want to miss it.

      For more simple editors for a quick text edit, my favorite is EditPlus [editplus.com]. It lets you choose between classical tabs and whitespace tabs, as how long (in characters) a tab in either mode should be treated, it has the auto-indent you mentioned, reacting to freely definable characters (for example, auto-indent forward after '{' or '(', and back after '}' or ')', respectively). Best of all, it lets you define these parameters independently for plain text, c/c++, java, HTML, Perl, etc., etc., as well as any number of custom syntaxes you may wish to import or define yourself. A small selection of useful features of a great tool. Disclaimer: I am in no way affiliated with Editplus or the company behind it, just a happy user.

    • Tabs versus Spaces: An Eternal Holy War. [jwz.org]
      Jamie Zawinski

      My opinion is that the best way to solve the technical issues is to mandate that the ASCII #9 TAB character never appear in disk files: program your editor to expand TABs to an appropriate number of spaces before writing the lines to disk. That simplifies matters greatly, by separating the technical issues of #2 and #3 from the religious issue of #1

      A very clever solution indeed. Apparently some clever bastard sovled this issue six years ago. Return t

    • Re:A standard tab length would be easier (Score:5, Insightful)

      by peterpi (585134) on Monday July 03 2006, @03:31PM (#15652241)
      I can't understand why people still find this a problem. It's so simple. Tabs indent, spaces line up. In other words

      • space means "move to the right by exactly one character width"
      • tab means "I want to indent, move across a bit". "A bit", and "across" mean whatever you like. It could be right8 chars, right 4 chars, left 2 chars, down 947565 chars, whatever you like. That's the beauty of it; everybody gets to view it in their favourite format.


      It's so simple, it's quite embarassing for the whole of the computer-literate society that people still get their kickers in a twist about it.

      Anybody who tries to lay down the law by saying that a tab must be 4, 8 or 2 characters' width has missed the point of the tab key completely.

      As for your wish, I'm willing to bet money that either vim or emacs will do it for you.

      • I'm sure a lot of things seem so simple when you're so ignorant of the actual issue [go-pear.org].

        Why does the PEAR coding standard insist on space-only indentation?
        Using spaces and avoiding tabs is the only way to ensure that a piece of code is rendered consistently in all editors and viewers. Many editors render tabs as 4 spaces, and a lot of editors, terminal programs and utilities render tabs as 8 spaces.

        • Re:A standard tab length would be easier (Score:5, Insightful)

          by peterpi (585134) on Monday July 03 2006, @05:01PM (#15652739)
          And they make the fundamental misunderstanding in the very first sentence! Why is consistency desireable? Why should my text editor render code consistently with yours? We could be using a different font in a differerent point size at a different resolution. Is that important too? I have white text on a black background on one machine, black on white white for the other. If you specifically need some lines of text to be lined up with each other (consistency within the confines of the document), use space. If you just need it to be shunted over to express intent, use tab. That way we can both set tab to look exactly how we want it to.

          eg: (---> means 'tab', '.' means 'space')


          void foo ()
          {
          --->if (something)
          --->{
          --->--->/* I like to format my comments so that
          --->--->.* the stars make a vertical line,
          --->--->.* but I don't care how much you like to
          --->--->.* indent */
          --->--->bool something = SomeLongFunction() &&
          --->--->.................Another()
          --->}
          }


          This code satisfies everybody with a good text editor. If you like 8 spaces, set your editor so. If I like 2, 7 or 3.14 I can set mine. Pressing space n times annoys everybody who likes 2n, n/2 or any other number of spaces.

          That way they can get on with arguing over important issues like the placement of {

          ;)

      • This is how I code, at least in C-like languages. You can set your tab length to whatever you want, and my sources still look pretty:

        int foo ()
        {
        //Every line starts with tabs:
        if (
        some_really_long_expression &&
        some_other_really_long_expression
        ) {
        DoSomethingClever(42);
        DoSomethingComplex(
        param1,
    • So far as I know, "tab" has always meant "Advance the carriage to the next tab stop" and has never meant "advance a fixed number of spaces". The default tab stop setting varies from program to program. In Word its on 1/2" boundaries, and in most editors its on 8-character boundaries.

    • A standard would be easier. Just have someone say "Tabs are now officially SOME_NUMBER spaces long, so fuck you."

      I thought they had...

      [History lesson]

      Typewriters - very early typewriters - had tab stops equivalent to 8 spaces. That was it; no ifs, no buts, no negotiation. Later models had the first tab stop equivalent to 8 spaces, then 2 or 3 adjustable tab stops inside that. Even later ones had the first stop adjustable was well.

      Y'see, the TAB key is short for "table" - it was designed to make it easy to

      • You might as well try and define what the 'end' key does. Or better still, define what the F7 key does.

        Tab is already standardized. It means either "move onto the next record" in tabular data, or in programming languages "indent". If you have a preference for how much like code to be indented, then you get to set your editor in accordance. Indenting code with tabs is far more considerate than indenting with spaces. Indenting with tabs says "Indent a little. I trust you to set your editor accordingly".

    • I do use the tab key as a means of stepping along a number of spaces but the resulting files has exactly the number of space characters that are necessary and no tab characters at all.

      Yeah. And this is exactly the way it should be today. In mature Emacs modes for example, pressing the TAB key doesn't necessarily mean that you insert an ASCII TAB character, instead it indents to the right place. Modern editors should take the burden of 'manual' indenting from the coder and instead let him focus on the

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