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Ask Slashdot: What Are the Strangest Features of Various Programming Languages? 729

itwbennett writes: Every programming language has its own unique quirks, such as weird syntax, unusual functionality or non-standard implementations -- things that can cause developers new to the language, or even seasoned pros, to scratch their heads in wonder (or throw their hands up in despair). Phil Johnson has rounded up some of the strangest — from the + operator in JavaScript to the trigraphs in C and C++ and indentation level in Python. What programming language oddities cause you the most grief?"
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Ask Slashdot: What Are the Strangest Features of Various Programming Languages?

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  • Powershell (Score:5, Interesting)

    by Anonymous Coward on Friday September 05, 2014 @12:21PM (#47835207)

    -eq as the equality operator in Powershell is pretty odd.

    • Per uses eq for string equality checks, making the distinction between that and == for numerics. I'm not sure that one is weird.

      Verilog has a nice one though ===, meaning two wires are in exactly equal states, including more abstract states like "don't care" or "high impedance", rather than simple == which is a logical comparison. It has no real physical meaning, it's purely for programming purposes.

      • by Vlad_the_Inhaler ( 32958 ) on Friday September 05, 2014 @12:58PM (#47835591) Homepage

        I'm from a different generation. When I was learning things there were attempts made to make languages somewhat failsafe by avoiding ambiguity. Then I saw the C syntax.
        - if (a = b) assigns the contents of b to a and executes the code following if b <> 0. Who the hell thought that would be a good idea?
        - sizeof(string) (I may have got the name of the function wrong) returns the length of a single byte rather than the length of the entire string. Who the hell thought that would be a good idea?
        - strings terminated by a binary zero rather than their physical size. Who the hell thought that would be a good idea?

        Kids grew up with this idiocy, I program in Fortran, Cobol, even Assembler to avoid that mess. Oh, and buffer-overruns have been a serious security problem for years now. Well what a f****** surprise.

        • Re:Powershell (Score:5, Informative)

          by angel'o'sphere ( 80593 ) on Friday September 05, 2014 @01:16PM (#47835779) Journal

          C was designed to be a portable assembler.
          In assembly it is very common to reuse the "register flags" that get set after an assignment.
          E.g. the famous and simple strcpy function in C (a two liner plus signature) is in 68k assembly also only a two liner:

                move.b (A0)+, (A1)+
                bne loop

          The loop runs until a zero value is moved.

          That does not return the size of a byte but the size of a pointer as a string is a pointer 'char's. Seems you missed the existence of the strlen function.

          - strings terminated by a binary zero rather than their physical size. Who the hell thought that would be a good idea?
          Well, age old argument. Basically a matter of taste or sadly a historical "evolution".
          Modern languages like Java and C# allow arbitrary long strings and store ofc the size.
          In older times we only had the Pascal world, where the first byte indicated the size of the string and the C world where a zero byte terminated the string.
          Other 'worlds' like Fortran and Cobol only had fixed sized strings and padded the end of the string with blanks.

          • by Comboman ( 895500 ) on Friday September 05, 2014 @02:06PM (#47836291)

            - strings terminated by a binary zero rather than their physical size. Who the hell thought that would be a good idea?
            Well, age old argument. Basically a matter of taste or sadly a historical "evolution".

            I'm pretty sure null-terminated strings come from the days of punch cards/punch tape where an unpunched area is read as null (binary zero). Wherever the data-entry clerk stopped typing was the end of the string and the string could be appended to latter (impossible with a non-zero end-of-string symbol or a string length in the header which can't be rewritten on card/tape).

        • by tepples ( 727027 ) <tepples@gmail.BOHRcom minus physicist> on Friday September 05, 2014 @01:19PM (#47835835) Homepage Journal

          if (a = b) assigns the contents of b to a and executes the code following if b 0. Who the hell thought that would be a good idea?

          If b is an expression that returns a reference to a newly allocated resource, such as fopen or malloc, this if statement represents trying to allocate a resource and then skipping the following compound statement if the allocation failed. It's what they had before exceptions, and it's what they still have on microcontrollers too small to have the overhead of a full-featured exception handler.

          strings terminated by a binary zero rather than their physical size. Who the hell thought that would be a good idea?

          Probably the same way that most popular operating systems store text files as a list of lines separated by newline characters, encoded as 0x0A on UNIX or Windows but 0x0D on Apple II or classic Mac OS. VMS is an exception in that its "non-stream" text files [sympatico.ca] have each line prefixed by its length.

        • Re: (Score:3, Informative)

          by LoneTech ( 117911 )

          - sizeof(string) (I may have got the name of the function wrong) returns the length of a single byte rather than the length of the entire string.

          A number of things misleading here, which do stem from C's archaic background: Firstly, sizeof is not a function (those parenthesis are not needed and only make it confusingly resemble a function call), it is a rather special operator both in that it looks like a name and operates on types instead of values. There is no string type at all. There are two types frequently used as strings, char arrays and char pointers; only in the case of the array would sizeof return the storage size (which is larger than th

          • by rmstar ( 114746 )

            Of course, the more you explain about C the less sensible it appears. ;)

            It's funny, really. [slideshare.net]


            both in C and certainly in C++, it is uncommon to see a screenful containing only well defined and conforming code.

            That's what proper language design is supposed to avoid. Oh well.

          • One of my favourites in C:

            int* a = ...
            2[a] = 5;

            Not sure if this is still allowed by the latest standards, but it used to work.This makes use of the fact that the bracket operator x[y] is syntactic sugar for *(x+y). So:

            a[2] = *(a + 2) = *(2 + a) = 2[a]

            Now try that somewhere else!

        • if (a = b) assigns the contents of b to a and executes the code following if b 0.

          It makes sense to me. The statement inside the () gets evaluated, and = is the assignment operator only (which is better than forcing it to double up as comparison operator, isn't it?). For return value, what else could it return?

        • Re:Powershell (Score:4, Insightful)

          by VGPowerlord ( 621254 ) on Friday September 05, 2014 @02:22PM (#47836433)

          - sizeof(string) (I may have got the name of the function wrong) returns the length of a single byte rather than the length of the entire string. Who the hell thought that would be a good idea?

          Hey, just because you don't know the language doesn't mean it's necessarily wrong. Documentation for sizeof would have told you that it's for telling you the size in bytes of datatypes on a particular system. It's often paired with malloc to allocate memory for something.

          The C specification is remarkably lax on the size of its numeric datatypes, too. To the point where eventually a bunch of bit-specific sizes were introduced because the basic versions weren't. example: uint32 is a 32-bit unsigned integer, where as uint is an unsigned integer that's 16-bits or larger depending on the platform.

          For that matter, even pointer size changes depending on systems. For instance, it's 4 bytes for 32-bit Intel systems and 8 bytes for 64-bit Intel systems.

        • by itzly ( 3699663 )

          - strings terminated by a binary zero rather than their physical size. Who the hell thought that would be a good idea?

          Zero termination is simpler, and more flexible. Also, it avoids having to choose the appropriate number of bytes for the size field. Besides, if you want strings with size field, it's simple enough to implement that yourself.

        • by spitzak ( 4019 )

          Null-terminated strings were considered superior to using a length because they allowed strings to be > 255 bytes long (using 16 bits for the length would allow longer counted strings, but at that time with 4K of memory nobody in their right mind would suggest wasting a byte like that!).

          Null-terminated strings also have the nice property that getting the "tail" is a very fast operation, since you just return a pointer to the middle. This meant that searches could return strings, rather than indexes. This

      • PHP does the same/similar, but the === checks not just the data contained but the data type since PHP uses untyped variables.


        $a=$b assigns the value in $b to $a
        $a==$b returns true if the value contained is the same.
        $a==$b returns true

        BUT... given
        $a===$b is FALSE since one is stored as a string and the other as an integer

        Which kinda makes sense for a language that has untyped variables.....

    • Re:Powershell (Score:4, Interesting)

      by asmkm22 ( 1902712 ) on Friday September 05, 2014 @01:31PM (#47835949)

      A lot of bash and *nix stuff is in PowerShell, which I think it's the point. I remember the first time I opened a session and instinctively typed "ls" without it giving an error.

  • by Anonymous Coward on Friday September 05, 2014 @12:24PM (#47835239)

    Posting a slideshow on Slashdot? Lame. What, was Buzzfeed not available?

    • by Anrego ( 830717 ) * on Friday September 05, 2014 @12:30PM (#47835307)

      I don't even bother with infoworld links any more. It'll be a bunch of slides with a sentence of text, an unrelated image, and ads everywhere (ads on the slides, ads before the slides, an add in the middle of the slideshow, and an ad at the end). Content wise, usually they find one or two interesting things, then fill the rest of the slots with stupid shit everyone already knows.

      • by Anrego ( 830717 ) *

        * itworld (reading another post where they messed it up, so I messed it up!)

      • by amicusNYCL ( 1538833 ) on Friday September 05, 2014 @12:43PM (#47835439)

        That was my experience. I opened the page, clicked Next past the intro slide, saw a picture of apples and oranges, some text talking about "+" in Javascript, clicked Next again, it faded out to show an ad that I blocked, and I closed the page. Bunch of crap.

      • I don't even bother with infoworld links any more....

        Earlier this week I removed ComputerWorld from my bookmarks. They just went through a site redesign, and the page content has dropped dramatically, plus there's an automatic slideshow scrolling horizontally on the top of your screen as you're trying to focus on and read something else on the page.

    • by Tukz ( 664339 ) on Friday September 05, 2014 @12:33PM (#47835339) Journal

      And not only that, the slides slides to advertisements WHILE YOU'RE READING THEM!
      Closed the tab at that point.

  • Database Identity (Score:3, Insightful)

    by Baby Duck ( 176251 ) on Friday September 05, 2014 @12:26PM (#47835255) Homepage
    It's outdated database security models that cause me the most grief. I don't want jsmith logging in from gatech.edu to be considered a DIFFERENT HUMAN BEING that jsmith logging in from whitehouse.gov. I want to say, there's ONE PERSON, John Smith, username jsmith, who is allowed to login from BOTH domains with the SAME PASSWORD and GRANTS. Nope. Can't do it. Newer versions MIGHT allow you to swap in your own authentication module instead, but NOT the authorization piece, so I'm still screwed!
    • I think it is the opposite of outdated. It used to be that jsmith was jsmith. Now, with all this fancy Windows Authentication, you can be guaranteed no end of hassle. For instance, at my company, our laptops are on a different domain than production, for some sort of security reason. However, one of the database servers is set up with windows authentication, which means, yup, you can't log into it from your laptop. You have to first remote desktop into something on the production domain, and then run SQL en
      • Maybe I'm missing something here, but why can't you just specify the domain name before the user name when you attempt to login to the database from your laptop?

    • by tepples ( 727027 )

      I want to say, there's ONE PERSON, John Smith, username jsmith, who is allowed to login from BOTH domains with the SAME PASSWORD and GRANTS.

      Same password, yes, that's what OpenID and OAuth-based authentication are for. But why would someone have the same grants on gatech.edu as on whitehouse.gov? Just because you're allowed to manage a professor's presence on Georgia Tech's web site doesn't mean you should be allowed to deface Barack Obama's site.

  • Infoworld... pass (Score:3, Insightful)

    by Anonymous Coward on Friday September 05, 2014 @12:26PM (#47835257)

    I envision an add filled slideshow with almost no content, and what content is there to be boring and well known so I’ll skip the article.

    To answer the question, most of perl seems to be built around bizarre unintuitive constructs that you just have to kinda know about, so pointing out any of that would seem unfair.

    In C, the first time I saw the size of elements of a struct specified (i.e. int something : 3) it threw me (and that’s a hard problem to google). It was being used to essentially overlay a struct onto a chunk of memory being received via an interface and extract values, which was actually kinda a cool use of the feature (though a comment woulda been nice unknown dev!).

    Some of the type erasure mechanics of Java can be a bit confusing the first time you hit up against them.

    The way javascript does dates, and timezones

    I dunno, most languages have their weird bits, but I can’t think of anything that is egregiously terrible.

    As far as tools, I'd say pacman (Arch's package manager) and git (yes, I'm an SVN fanboy) have the highest concentration of "the hell were they smoking" flags and usage instructions. Pacman seemed to pick it's arguments randomly, and git seems to go straight off the deep end if you want to do anything non-trivial.

    • Re: (Score:2, Informative)

      by sconeu ( 64226 )

      In C, the first time I saw the size of elements of a struct specified (i.e. int something : 3) it threw me

      Considering that you misunderstand/misunderstood the syntax, I'm not surprised.

      It's not saying it's a 3 byte int, it's saying it's a 3-bit field.

  • Goddamn AT&T assembler syntax with its reversed operands. Quick, you want to compare two registers, and jump if %rdi %rax. Which order do you place the operands to the comparison, and what's the predicate to use on the jump? Drives me nuts.

    • Re:cmp %rdi,%rax (Score:5, Interesting)

      by bluefoxlucid ( 723572 ) on Friday September 05, 2014 @01:38PM (#47836033) Homepage Journal

      I always liked the target-first approach of Intel. Like strcpy(dst, src). I know I'm mucking with (dst) string, and not doing anything with (src). The same with (MOV %eax, 0xdeadbeef).

      Imagine strcpy(src,dst), which many people would say is more logical because you're saying "Perform a string copy from (src) to (dst)." We say "Copy from source to destination" all the time--it's how we think, right? And then: strncpy(src,dst,32). So with strcpy(), the last argument is the thing we mess with; while strncpy() it's some argument in the middle.

      This is why strcpy(dst,src) and strncpy(dst,src,len) are set: the first argument is the target. These calls immediately tell you what they actually change. printf() changes nothing, but uses the first argument as its format--it emits a modified content of the first argument based on subsequent arguments; sprintf() changes the first argument to a modified copy of the second argument using all further arguments. If something is changed, it's the first things that are changed.

      In Intel assembly, a glance down the left side of the screen rapidly tells you what's roughly going on. You don't need to read the whole line; you just look at opcodes and targets, quickly recognizing which opcodes modify their targets. This immediately tells you flow; and attaching the source data for the modification provides you with logic. This is less decoding than trying to interpret an individual opcode, rearrange it in your head, extract its behavior, extract its logic, and build incrementally with that.

  • Lua[0]? (Score:5, Interesting)

    by Saei ( 3133199 ) on Friday September 05, 2014 @12:29PM (#47835289)
    Lua's standard is, for things like arrays, to start counting from 1. The unlearning of old habits made this a hard adjustment.
    • Re:Lua[0]? (Score:5, Funny)

      by Anonymous Coward on Friday September 05, 2014 @12:38PM (#47835395)

      Bookkeepers, shepherds, scientists and mathemaitcians have for centuries counted starting with 1. It is recent computer scientists that started this crazy standard break, as if they knew better how to count.

      • Re:Lua[0]? (Score:4, Interesting)

        by T.E.D. ( 34228 ) on Friday September 05, 2014 @08:33PM (#47838837)

        It is recent computer scientists that started

        Not "computer scientists". Just C programmers. The first two languages designed, Fortran and Cobol, start at 1. Algol('68) and all the languages descended from or influenced by it let the programmer set the starting bound (this includes Ada, Pascal and all the other Wirth languages).

        Pretty much every language that uses 0 as the only allowable starting index is either descended from C, or borrowed large amounts of its syntax from it. (Some BASICs use 0, but that language is so egregiously unstandardized that its tough to say anything about it with certainty).

    • by Anrego ( 830717 ) *

      In general I found it difficult to twist my brain into doing things the lua way.

      It seems to go out of it's way to be slightly different.

    • I would say it's more a weird feature of C to count from 0 (and everything copied it). Fortran and COBOL count from 1 (in fact, Fortran counts from whatever the hell you want it to)
    • Most languages start array indices with 1 ... only coming from C later languages that adopted C "syntax" also adopted the start with zero paradigm.

      But of course, habits cause problems. In Pascal you count until 'i == end' in C/Java etc. you count while 'i < end' ... had the same trouble often enough in reverse transition :D

  • by Anonymous Coward on Friday September 05, 2014 @12:29PM (#47835291)

    Requiring a graphics card and special character set to program in the language:

    Because of the unusual character set, many programmers use special keyboards with APL keytops for authoring APL code. Although there are various ways to write APL code using only ASCII characters, in practice, it is almost never done.


    • by msauve ( 701917 )
      I used to have a Centronics 761 teleprinter with an APL keyboard/charset. I never used it for APL, but it sure looked cool.
  • by Ken D ( 100098 ) on Friday September 05, 2014 @12:29PM (#47835299)

    Since this operator exists in C/C++, Java and Perl at least, it's hardly obscure

    • By now, the only strange thing about the ternary operator condition ? value_if_true : value_if_false is how PHP has the operator's associativity backwards from everything else. Everything else interprets a?b:c?d:e as a?b:(c?d:e), where a chain of ternary operators means use the value associated with the first true condition. It's equivalent to SQL's case when a then b when c then d else e end. PHP, on the other hand, interprets a?b:c?d:e as (a?b:c)?d:e, which means using one condition to select which other
  • I understand in some learning languages (Apple ][e flavor of Basic comes to mind) it can useful for beginners. But why have it languages like C#, VB,NET and even JavaScript? It would make everyone's life easier and most code run faster if you pushed your objects to strongly type variables.
    • Re: (Score:3, Informative)

      by Anonymous Coward

      The "var" in C# is not a variant. It's simply a syntactic shortcut to allow the developer to not repeat the type in the declaration if the type can be inferred from the initialization expression. The behavior is identical to C++ "auto".

      var x = 1; // x is an int
      x = "1"; // compiler error, x is an int and cannot be set to a string

      var y; // compiler error, the type cannot be inferred
      var y = null; // compiler error, the type cannot be inferred

      • I realize that but its seems a waste. My point was that you should already know your data types. I like the readability of strongly typed code. You also make you compiler and debugger work extra. On small stuff no big deal. But on large projects those extra compiling seconds can become minutes easily. Also I've had a few cases where when I've done compares on C# compiled code the strongly typed program usually came out smaller.
    • Because variants are useful when you want to (or most common, you need to) make a generic function to handle some information where you have no way of knowing if the input parameter will be a string, integer, long, etc. Of course it is slower than dealing with a defined type, but is usually more convenient than trying to create a separate function for each possible entry type.
    • by i kan reed ( 749298 ) on Friday September 05, 2014 @12:41PM (#47835425) Homepage Journal

      I can tell you why C# has it.

      The normal way intellisense works, you often have to do the end of your line of code then go back to the beginning to type out what type of variable the method you're calling returns now that you know. Var obviates this task by going "oh, of course, it's the type returned by this method".

      As usual with language features, it comes from us developers being very very very lazy people.

  • Perl: TMTOWTDI (Score:5, Insightful)

    by i_want_you_to_throw_ ( 559379 ) on Friday September 05, 2014 @12:29PM (#47835305) Journal
    I used to think that Perl's feature of "There's More Than One Way To Do It" was great until I had to start modifying and maintaining the code of other developers, (several over the years). 20+ years I've been with Perl and I gotta say that through the years this has probably caused me more frustration than anything. Python, comparatively speaking, is a dominatrix and I'm starting to enjoy "There's Only One Way To Do It".
    • Re: (Score:3, Interesting)

      by mark-t ( 151149 )

      I think I'd have to agree with this. I never nailed it down to that particular aspect of perl before now, but I can easily see how this characteristic of perl makes it very difficult to identify idioms in the language. With so many ways to do things that you can't always quickly identify what is being done simply by looking at the source code, unless it has been quite rigorously commented.

      Code written in an idiomatic style rarely needs much commenting, because people familiar enough with the language t

    • Re:Perl: TMTOWTDI (Score:5, Interesting)

      by i kan reed ( 749298 ) on Friday September 05, 2014 @12:46PM (#47835485) Homepage Journal

      You just haven't run into another python developer who's "clever" enough yet.

      for a,b,c,d in [x.q for x in y if x.z]+[x.r for x in y if x.z]:
              a.m=b or c and d

      (none of these variables are boolean)

    • I used to think that Perl's feature of "There's More Than One Way To Do It" was great until I had to start modifying and maintaining the code of other developers,

      Maintaining the code of others? Heck, I have found in perl, that it was easier to rewrite a program than try to debug it even if I wrote the original program.

  • I think the trend on the web towards using slideshows when prose would work better is really quirky. Since each slide acts like a page hit, slideshows are a good way to drive up the ad revenue that is based upon page hits....
  • The alter command in COBOL.

    Lo, these many years ago, when I'd just read it in a manual, and discussed it with my boss (who would have given Dilbert's a run for his money, but...) and asked him if he'd defenestrate anyone using it before or after firing them, and he told me before.....


  • by sconeu ( 64226 ) on Friday September 05, 2014 @12:36PM (#47835373) Homepage Journal

    Namely, the >> symbol. Because templates use angle brackets for template parameters, if you had a nested template such as T<int, T1<double> >, you HAD to put the space between the two closing angle brackets. Otherwise the lexer would interpret the two angle brackets as the shift operator.

  • by bobbied ( 2522392 ) on Friday September 05, 2014 @12:40PM (#47835415)

    That pesky ";" statement terminator... I guess you had to uses something, but it causes me the most trouble..

    C, C++, Pascal, Perl, Java, C#, bash/sh, ksh, JavaScript..... The list goes on..

  • The iota enumerator in Golang is elegant and unique. Writing idiomatic Golang code is so implicit in the language itself that I've been able to easily read almost any Go code I find.

    http://golang.org/doc/effectiv... [golang.org]

  • by jfbilodeau ( 931293 ) on Friday September 05, 2014 @12:46PM (#47835483) Homepage

    How is that a language quirk for JavaScript? The + operator has been used for string concatenation in a number of programming languages (C++, Java, Python...) long before JavaScript. It is still implemented as such in newer programming languages like C#.

    • by TheDarkMaster ( 1292526 ) on Friday September 05, 2014 @01:03PM (#47835651)
      The difference is that the "+" operator in a strong-typed language works without causing nasty surprises for you.
  • by Parker Lewis ( 999165 ) on Friday September 05, 2014 @12:52PM (#47835533)
    I started with Ruby about 1 year ago. And until now, work with strings and the symbols is not natural yet to me. I mean, most of the languages I handled until now have only strings.
  • by lowen ( 10529 ) on Friday September 05, 2014 @12:59PM (#47835605)

    Heh, all of Intercal is strange.... but COMEFROM is just.... elegant.

    It's been implemented for Python, of all things.....

    See: https://en.wikipedia.org/wiki/... [wikipedia.org]

    • Elxsi Fortran had it long ago.

      Richard Maine in FORTRAN IV program illustrating assigned GO TO on web site [google.com]

      The Elxsi compiler in the mid 80's actually implemented the comefrom
      statement (and several variants) as a continuation of this spoof. It
      wasn't documented, but I found out about it when Ralph Merkle (one of
      the developers) suggested that I might be amused by looking at a certain
      area in the compiler executable file. When I did so, I found a list of
      strings containing mostly familliar Fortran keywords. Amidst those, I
      spotted comefrom. A quick check verified that the statement actually
      compiled and worked as "expected".

      I later heard that the statement was pulled from the compiler after a
      customer submitted a bug report (I think it was a
      performance/optimization issue) related to the comefrom statement
      implementation. The joke wasn't worth actually investing scarce support
      resources on.

  • by Framboise ( 521772 ) on Friday September 05, 2014 @01:00PM (#47835613)

    Assigning a number or a list in Python and many other languages (Julia) is a different operation. Such as

    >>> a = 2
    >>> b = a
    >>> a = 1
    >>> b

    >>> a = [2]
    >>> b = a
    >>> a[0] = 1
    >>> b

    Octave (Matlab) is more consistent on this point, every assignement is a memory copy.

    • Assigning a number or a list in Python and many other languages (Julia) is a different operation. Such as

      >>> a = 2
      >>> b = a
      >>> a = 1
      >>> b

      >>> a = [2]
      >>> b = a
      >>> a[0] = 1
      >>> b

      Octave (Matlab) is more consistent on this point, every assignement is a memory copy.

      I'd find it alarming if Python *didn't* act that way! In Python, everything is an object and objects are passed by reference; hence altering the contents of "a" in your second example is clearly going to alter the contents of "b", since they're references to the same object. In the first case, you're altering *which object* "a" points to. It's completely consistent.

      The alternatives would be crazy (from an OO perspective).

      To make your second example act like your first one, we would need to *pass* everything

  • Python False = True (Score:5, Interesting)

    by underqualified ( 1318035 ) on Friday September 05, 2014 @01:00PM (#47835619)
    False and True are variables and you can assign one to the other. False = True print False Not that anyone sane would do this in real code, but the thought is still scary.
  • by NotInHere ( 3654617 ) on Friday September 05, 2014 @01:03PM (#47835645)

    use whitespace [wikipedia.org]. Be warned, several problems have been reported [slashdot.org] when posting source code to the internet.

  • IDL language (Score:4, Interesting)

    by Khashishi ( 775369 ) on Friday September 05, 2014 @01:13PM (#47835747) Journal

    Odd integers are true; even integers are false.

    Arrays can be indexed with () or []. This leads to namespace problems with functions which are also called with (). For example:
    error: undefined variable a.
    If you want to call function a, you have to forward declare it for this reason.
    There's a different syntax for procedures (which don't have a return value) and functions (which do).

    It is required to assign the result of a function to something. You have to write
    dummy = foo(1,2,3)
    as writing
    will give an error.

    Most of the time, a single element array is treated the same as a scalar. But not always, and not being very careful will lead to weird errors.
    There are no zero length arrays.
    An array can be length 1; a multidimensional array can be length [1,2,2], but a multidimensional array cannot be length [2,1,1]. If the last dimension has length 1, it simply vanishes to a smaller dimension, unless already 1 dimensional. Example:
    a = make_array(1,2,2)
    ; a has dimensions [1,2,2]
    a = make_array(2,1,1)
    ; a has dimensions [2]
    This means special code must be written to handle any array operations that might end with last dimension 1.

    Array slices are weird.
    b = a[3,*,2]
    means to take a slice of a along the second dimension. I'd expect the answer to be 1 dimensional, since there's only 1 scan in the slice. But the result has dimensions [1,3]
    On the other hand, a[3,2,*] has dimensions [1,1,3], and a[*,3,2] has dimensions [3]. It makes sense in a convoluted way, but it sucks.

  • LISP (Score:4, Interesting)

    by whitroth ( 9367 ) <`whitroth' `at' `5-cent.us'> on Friday September 05, 2014 @01:18PM (#47835809) Homepage

    Ok, someone has to mention lisp.

    Item from 15 or so years ago: a guy posted online that he'd broken into the Pentagon's computers, and found the code for SDI, and it was written in lisp. He didn't want to break US security, but he did post the last five lines of the code.... (stupid slashdot edit filter - 5 lines of ) was not junk... at least, not in lisp....)


    • That is why you NEVER EVER write Lisp code with an editor that's not parenthesis-aware. I've tried it. Don't make my mistake.

  • by Tridus ( 79566 ) on Friday September 05, 2014 @01:18PM (#47835811) Homepage

    http://stackoverflow.com/quest... [stackoverflow.com]

    That's a list of very strange language features. Unsurprisingly, Javascript makes many, many appearances.

  • by Warbothong ( 905464 ) on Friday September 05, 2014 @01:43PM (#47836089) Homepage

    def mkCounter():
            c = 0
            def counter():
                    c = c + 1
                    return c
            return counter

    count = mkCounter()
    print str(count())
    print str(count())
    print str(count())

    You'd expect "1", "2" and "3", right? Wrong!

    $ python test.py
    Traceback (most recent call last):
        File "test.py", line 9, in
            print str(count())
        File "test.py", line 4, in counter
            c = c + 1
    UnboundLocalError: local variable 'c' referenced before assignment

    When Python parses the definition of "counter", it sees the assignment "c = ..." and assumes that we must be defining a local variable "c", so it creates a slot in "counter" to contain "c". This local slot shadows the "c" inherited from "mkCounter", so when we get to evaluating "c + 1" we get this "referenced before assignment" error.

    Note that it's perfectly fine to *use* inherited variables, just not to *assign* them:

    def mkPrinter(s):
            def printer():
                    print s
            return printer

    p = mkPrinter("hello world")

    This prints "hello world" as we'd expect.

  • by ClickOnThis ( 137803 ) on Friday September 05, 2014 @01:53PM (#47836191) Journal

    This was a stunner for me when I first encountered it. When you mix double and int types in Matlab, it demotes the double to an int! Same with float and int.

    Of course, you must create the int explicitly as such (double is the default) but I mean, WTF Matlab??

  • by Chelloveck ( 14643 ) on Friday September 05, 2014 @02:18PM (#47836399) Homepage

    The C pre-processor. The whole thing. The CPP is without a doubt the biggest WTF in language design. Hey, this C language is neat and all, but how about if we make it so that before you compile it you have to run it through a whole separate language processor with different syntax designed to do string substitution? And let's use that language to implement comments. And hey, how about using it to import common files? But since it's really just a string substitution, the import really just dumps a verbatim copy of the common file into the one being processed. If you have two identical include lines you get two copies of the common file inserted. Wouldn't that be *great*!?

    Okay, I understand the historical context and why it made sense at the time. I really do. But from a modern perspective it's definitely not in any way the sane way to do it.

    And for an honorable mention, how about the use of leading whitespace in Makefiles? Not only is leading whitespace significant, starting a line with spaces has a different meaning than starting a line with tabs!

  • MSSQL (Score:4, Interesting)

    by netsavior ( 627338 ) on Friday September 05, 2014 @02:34PM (#47836507)
    I love the various different parsers MSSQL uses, and how very wrong things can go. Run this in SQL management studio and it will work fine... run it from the command line and it will give the below error. It will find \r\nGO\r\n and treat it as a block terminator... even if it appears in comments. This is the only command that it will find and execute within comments.

    declare @var as int
    set @var = 10
    print @var
    this is totally in the comments
    print @var
    output -
    Msg 137, Level 15, State 2, Line 1 Must declare the scalar variable "@var".
  • by Required Snark ( 1702878 ) on Friday September 05, 2014 @02:50PM (#47836647)
    Metapost is a part of Knuth's TeX suite of languages. http://en.wikipedia.org/wiki/MetaPost [wikipedia.org]. It is a graphic language that emits Postscript and supports spline line drawing. It was derived from Metafont, the font generation language for TeX.

    First, Metapost is implemented as a macro language, so it is similar to C shell languages in the way it is evaluated. The symbols x, y, and z are predefined macros. For a location x the construct 3x is three times x. There are built in lengths, so 2cm and 1in are lengths. You can extend the language by defining you own macros for prefix or uinary and binary operations, which is the way that many of the operators are implemented.

    The if and loop syntax

    if boolean1 : expr1; else: expr2; elseif boolean2: expr3; fi

    for i=1 step t until n: statement; statement; endfor

    There are four levels of precedence. This is why multiplication by a constant can be expressed by putting a number in front of a value.

    These are just some of the syntax features. The data types include splines, transforms, colors and numeric pairs for points. Built in operations can find points where two curves intersect and sub-curve sections between intersections.

    It's fun in a strange fashion, and you can make some interesting geometrical pictures [loria.fr].

  • by david_thornley ( 598059 ) on Friday September 05, 2014 @04:03PM (#47837247)
    : CELEBRATE FORTH LOVE IF HONK THEN ; and remember that : ? . ! ; is a straightforward part of the language definition.
  • Platform lock-in (Score:4, Insightful)

    by Shompol ( 1690084 ) on Friday September 05, 2014 @04:39PM (#47837511)
    Platform lock-in is the strangest feature of some languages that purposely defeat all the progress we made since Assembler. This is why I will never C#

"If you lived today as if it were your last, you'd buy up a box of rockets and fire them all off, wouldn't you?" -- Garrison Keillor