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That boolean assignment operator was addressed. Whether or not C++ has them (it doesn't) is exactly the point of that code snippet. They do exist in other lang

by lucumo 5y ago

That boolean assignment operator was addressed. Whether or not C++ has them (it doesn't) is exactly the point of that code snippet. They do exist in other languages. ES has it in exactly that form. Java has it in the |= form, not to be confused with the bitwise OR of the same form. Whether or not these short-circuit is not all that interesting for most boolean logic. (Though it can be useful to know if these are used as hacky error-handling and default-setting. It depends on how you read "something" whether or not that's going on here.)

HWR_14 5y ago
> That boolean assignment operator was addressed. Where and when? Because I was the only person alluding to it, and the replies to my post. > Whether or not C++ has them (it doesn't) is exactly the point of that code snippet. C++ has boolean assignment operators that operate the way that the code is clearly meant to operate. That code does not have have a valid one. Where do you think Java got them from?
- megous 5y ago
  C++ does not have boolean assignment operator in a sense the ||= syntax works in ES. https://www.w3schools.com/cpp/trycpp.asp?filename=demo_oper_ass8 https://www.w3schools.com/cpp/trycpp.asp?filename=demo_oper_... ||= will not assign anything unless the LHS variable is falsy. It will not even evaluate the right side unless LHS is falsy. |= will work the same in C++ and ES mostly (depending on types)
  - HWR_14 5y ago
    I'm just thrown for a loop. Why is the default to assume I'm familiar with the ||= operator in ES? The fact that the ||= operator short circuits makes sense from an optimization point of view. I will maintain that there is no good use for the correctness (as opposed to optimization) of the code to depend on that feature.
- lucumo 5y ago
  > > That boolean assignment operator was addressed. > Where and when? Because I was the only person alluding to it, and the replies to my post. The words "boolean assignment operator" are in the first sentence after the code snippet in megous' post. > C++ has boolean assignment operators that operate the way that the code is clearly meant to operate. That code does not have have a valid one. Where do you think Java got them from? As far as I can tell the |= operator in C++ is the same as in C, i.e. a bitwise OR operator. It works for booleans due to their bit pattern, but it's not the same. My C++ knowledge is extremely limited, so I looked it up and I may be misinformed though. Java's |= is different for ints and boolean. There are no bitwise operators for booleans: bool1 | bool2 is a strict logical operation (that doesn't short-circuit). bool1 |= bool2 is a logical operation that will fail when other types are mixed in. int1 |= int2 is a bitwise operation. Java does not have a short-circuiting ||= operation (but ES does). For the most part these differences aren't that important, but they do trip people up when switching between languages.
  - HWR_14 5y ago
    > As far as I can tell the |= operator in C++ is the same as in C, i.e. a bitwise OR operator. This is true. > It works for booleans due to their bit pattern, but it's not the same. This makes less sense. A bool in c++ is just an integer value with few inputs. It is, as far as I can tell, the exact same. > Java's |= is different for ints and boolean. Java has bool and int as different types. There were versions of C++ compilers that just straight out had bool as a typedef of int.

by lucumo 5y ago

HWR_14 5y ago

> That boolean assignment operator was addressed. Where and when? Because I was the only person alluding to it, and the replies to my post. > Whether or not C++ has them (it doesn't) is exactly the point of that code snippet. C++ has boolean assignment operators that operate the way that the code is clearly meant to operate. That code does not have have a valid one. Where do you think Java got them from?

megous 5y ago
C++ does not have boolean assignment operator in a sense the ||= syntax works in ES. https://www.w3schools.com/cpp/trycpp.asp?filename=demo_oper_ass8 https://www.w3schools.com/cpp/trycpp.asp?filename=demo_oper_... ||= will not assign anything unless the LHS variable is falsy. It will not even evaluate the right side unless LHS is falsy. |= will work the same in C++ and ES mostly (depending on types)
- HWR_14 5y ago
  I'm just thrown for a loop. Why is the default to assume I'm familiar with the ||= operator in ES? The fact that the ||= operator short circuits makes sense from an optimization point of view. I will maintain that there is no good use for the correctness (as opposed to optimization) of the code to depend on that feature.
lucumo 5y ago
> > That boolean assignment operator was addressed. > Where and when? Because I was the only person alluding to it, and the replies to my post. The words "boolean assignment operator" are in the first sentence after the code snippet in megous' post. > C++ has boolean assignment operators that operate the way that the code is clearly meant to operate. That code does not have have a valid one. Where do you think Java got them from? As far as I can tell the |= operator in C++ is the same as in C, i.e. a bitwise OR operator. It works for booleans due to their bit pattern, but it's not the same. My C++ knowledge is extremely limited, so I looked it up and I may be misinformed though. Java's |= is different for ints and boolean. There are no bitwise operators for booleans: bool1 | bool2 is a strict logical operation (that doesn't short-circuit). bool1 |= bool2 is a logical operation that will fail when other types are mixed in. int1 |= int2 is a bitwise operation. Java does not have a short-circuiting ||= operation (but ES does). For the most part these differences aren't that important, but they do trip people up when switching between languages.
- HWR_14 5y ago
  > As far as I can tell the |= operator in C++ is the same as in C, i.e. a bitwise OR operator. This is true. > It works for booleans due to their bit pattern, but it's not the same. This makes less sense. A bool in c++ is just an integer value with few inputs. It is, as far as I can tell, the exact same. > Java's |= is different for ints and boolean. Java has bool and int as different types. There were versions of C++ compilers that just straight out had bool as a typedef of int.