25 ms·

Today I learned that Go does not support the ternary operator. that's sad :(

by Sembiance 9y ago

CamperBob2 9y ago
Or bitwise OR and XOR operators, according to the article? That's a bit hard to believe, no pun intended.
- Beanis 9y ago
  Bitwise OR and XOR are supported on ints. It doesn't work on bools, but there are equivalents: https://play.golang.org/p/GCAFwx03pi https://play.golang.org/p/GCAFwx03pi
- plorkyeran 9y ago
  Bitwise OR and XOR on bools. Bitwise XOR is just !=, so it's useless. Bitwise OR isn't identical to any other operators, but writing code which specifically relies on side-effects of a function on the RHS of an OR does not strike me as the sort of thing that the Go designers would approve of.
  - deleted 9y ago
    [deleted]
  - CamperBob2 9y ago
    Bitwise OR is equivalent to addition, but IMHO it makes more sense to omit support for addition on bools than to omit support for the classical boolean operators supported by C++. If for no other reason than to make existing C++ code easier to port.
    - wbl 9y ago
      Addition on bools is XOR.
      - CamperBob2 9y ago
        Not by C++'s convention. It may be compiler-dependent, but all of the compilers I have within easy reach treat addition of bools as an 'or' operation. bool a = true; bool b = true; bool c = a + b; This leaves c set to true. Basically it gets promoted to int, turned into a value of 2, and demoted back to bool. Either way it's highly nonstandard not to implement a bitwise-or operation on a boolean type. It's a violation of the "principle of least surprise" as well as a portability hazard. No upside that I can imagine.
        asveikau 9y ago
        I have been writing C for a while and never saw anyone add bools with +. Why do this when there is completely unambiguous || ? I get suspicious of being fast and loose with conversions between int and bool. This is implicitly required when working with operators like &&, ||, ==, etc., and working with pre-C99 bools and library typedefs. But assigning anything other than 1 or 0 is asking for problems. There is a whole class of bugs that shows up in security bugs involving assigning someone's machine-word-sized Boolean expression into someone else's byte sized bool, losing bits, and flipping from true to false. I sometimes feel there is a ^^ operator that should be there and is missing, in the same way that we have && and || corresponding to & and |. I have occasionally faked it with a macro: #define XOR(A,B) (((A) ? 1 : 0) ^ ((B) ? 1 : 0)) The ? here eliminates the problems from using larger != 1 quantities as true, as above.
Twirrim 9y ago
Gah.. I hate the ternary operator. Not that it's necessarily a bad thing in and of itself, but every time I've come across it in code, I've ultimately had to yank it out because I've needed to support an additional possibility. I don't get what value it really supplies, and it seems like people are really fond of using it in the wrong places.
- userbinator 9y ago
  I don't get what value it really supplies, and it seems like people are really fond of using it in the wrong places. It's a conditional expression , not a statement, and particularly helps simplify things like if(foo) someVeryVeryLongExpressionEvaluatingToAnLvalue = someShortRvalue; else someVeryVeryLongExpressionEvaluatingToAnLvalue = otherShortRvalue into someVeryVeryLongExpressionEvaluatingToAnLvalue = foo ? someShortRvalue : otherShortRvalue; I suppose to really "get" what the ternary is useful for, you have to have some experience with a more functional programming language, focusing on the flow of the data itself. There, multiply-nested ternaries are really the norm for what you'd otherwise call "control flow" in non-functional languages, and structures like this are common: value = isAtrue ? A_value : isBtrue ? B_value : isCtrue ? C_value : D_value ; (Does not work in PHP, but every other language with a ternary will interpret that as a compact alternative to the far more cumbersome if/else --- especially if coding standards dictate braces on their own line.)
  - skocznymroczny 9y ago
    I don't like the ternary operator ?, because it's not obvious: xyz = foo ? bar : baz; What does it mean? Which is the condition? which is the true, which is the false value? It's not obvious. In Python it is much more clearer: xyz = bar if foo else baz
    - bshimmin 9y ago
      I honestly struggle to understand how a traditional ternary like this isn't obvious. The bit before the question mark is the condition (er, like a question, which ends with a question mark), then the other two bits are for true and false in the order you would expect. I will freely admit I try and avoid nested ternaries, which I personally find hard to read.

Today I learned that Go does not support the ternary operator. that's sad :(

CamperBob2 9y ago

Or bitwise OR and XOR operators, according to the article? That's a bit hard to believe, no pun intended.

Beanis 9y ago
Bitwise OR and XOR are supported on ints. It doesn't work on bools, but there are equivalents: https://play.golang.org/p/GCAFwx03pi https://play.golang.org/p/GCAFwx03pi
plorkyeran 9y ago
Bitwise OR and XOR on bools. Bitwise XOR is just !=, so it's useless. Bitwise OR isn't identical to any other operators, but writing code which specifically relies on side-effects of a function on the RHS of an OR does not strike me as the sort of thing that the Go designers would approve of.
- deleted 9y ago
  [deleted]
- CamperBob2 9y ago
  Bitwise OR is equivalent to addition, but IMHO it makes more sense to omit support for addition on bools than to omit support for the classical boolean operators supported by C++. If for no other reason than to make existing C++ code easier to port.
  - wbl 9y ago
    Addition on bools is XOR.
    - CamperBob2 9y ago
      Not by C++'s convention. It may be compiler-dependent, but all of the compilers I have within easy reach treat addition of bools as an 'or' operation. bool a = true; bool b = true; bool c = a + b; This leaves c set to true. Basically it gets promoted to int, turned into a value of 2, and demoted back to bool. Either way it's highly nonstandard not to implement a bitwise-or operation on a boolean type. It's a violation of the "principle of least surprise" as well as a portability hazard. No upside that I can imagine.
      - asveikau 9y ago
        I have been writing C for a while and never saw anyone add bools with +. Why do this when there is completely unambiguous || ? I get suspicious of being fast and loose with conversions between int and bool. This is implicitly required when working with operators like &&, ||, ==, etc., and working with pre-C99 bools and library typedefs. But assigning anything other than 1 or 0 is asking for problems. There is a whole class of bugs that shows up in security bugs involving assigning someone's machine-word-sized Boolean expression into someone else's byte sized bool, losing bits, and flipping from true to false. I sometimes feel there is a ^^ operator that should be there and is missing, in the same way that we have && and || corresponding to & and |. I have occasionally faked it with a macro: #define XOR(A,B) (((A) ? 1 : 0) ^ ((B) ? 1 : 0)) The ? here eliminates the problems from using larger != 1 quantities as true, as above.

Twirrim 9y ago

Gah.. I hate the ternary operator. Not that it's necessarily a bad thing in and of itself, but every time I've come across it in code, I've ultimately had to yank it out because I've needed to support an additional possibility. I don't get what value it really supplies, and it seems like people are really fond of using it in the wrong places.

userbinator 9y ago
I don't get what value it really supplies, and it seems like people are really fond of using it in the wrong places. It's a conditional expression , not a statement, and particularly helps simplify things like if(foo) someVeryVeryLongExpressionEvaluatingToAnLvalue = someShortRvalue; else someVeryVeryLongExpressionEvaluatingToAnLvalue = otherShortRvalue into someVeryVeryLongExpressionEvaluatingToAnLvalue = foo ? someShortRvalue : otherShortRvalue; I suppose to really "get" what the ternary is useful for, you have to have some experience with a more functional programming language, focusing on the flow of the data itself. There, multiply-nested ternaries are really the norm for what you'd otherwise call "control flow" in non-functional languages, and structures like this are common: value = isAtrue ? A_value : isBtrue ? B_value : isCtrue ? C_value : D_value ; (Does not work in PHP, but every other language with a ternary will interpret that as a compact alternative to the far more cumbersome if/else --- especially if coding standards dictate braces on their own line.)
- skocznymroczny 9y ago
  I don't like the ternary operator ?, because it's not obvious: xyz = foo ? bar : baz; What does it mean? Which is the condition? which is the true, which is the false value? It's not obvious. In Python it is much more clearer: xyz = bar if foo else baz
  - bshimmin 9y ago
    I honestly struggle to understand how a traditional ternary like this isn't obvious. The bit before the question mark is the condition (er, like a question, which ends with a question mark), then the other two bits are for true and false in the order you would expect. I will freely admit I try and avoid nested ternaries, which I personally find hard to read.