That’s the way the language was designed. It is consistent with most languages. Having a variable declaration return anything other than undefined is meaningless, because you can’t ever use the var keyword in an expression context. Having assignment be an expression not a statement is useful when you want to set many variable to the …
No, they are different operators. The copy constructor is for creating a new object. It copies an existing object to a newly constructed object.The copy constructor is used to initialize a new instance from an old instance. It is not necessarily called when passing variables by value into functions or as return values out of …
This is just guesswork on my part, but: 1. It’s hard to implement this in a single-pass compiler Lua’s bytecode compiler is implemented as a single-pass recursive descent parser that immediately generates code. It does not parse to a separate AST structure and then in a second pass convert that to bytecode. This forces some …
Why did the logical operators get left out? Is there a good technical reason why it is hard? They didn’t. You can do &= or |= or ^= if you want. bool b1 = false; bool b2 = true; b1 |= b2; // means b1 = b1 | b2 The || and && operators do …
In an assignment statement, the right-hand side is always evaluated fully before doing the actual setting of variables. So, x, y = y, x + y evaluates y (let’s call the result ham), evaluates x + y (call that spam), then sets x to ham and y to spam. I.e., it’s like ham = y …
First of all: that’s an interesting question, but should never come up in “real code”, as assigning to the variable you call in the very same line is confusing even if you know how it works. What happens here is these 3 steps: figure out which object to call the method on (i.e. evaluate the …
A bit of clarification as to why it’s preferable to return by reference for operator= versus return by value — as the chain a = b = c will work fine if a value is returned. If you return a reference, minimal work is done. The values from one object are copied to another object. …
I advocated for having assignments return the value assigned rather than unit. Martin and I went back and forth on it, but his argument was that putting a value on the stack just to pop it off 95% of the time was a waste of byte-codes and have a negative impact on performance.
Reason The operators &&= and ||= are not available on Java because for most of the developers these operators are: error-prone useless Example for &&= If Java allowed &&= operator, then that code: bool isOk = true; //becomes false when at least a function returns false isOK &&= f1(); isOK &&= f2(); //we may expect …
The |= is a compound assignment operator (JLS 15.26.2) for the boolean logical operator | (JLS 15.22.2); not to be confused with the conditional-or || (JLS 15.24). There are also &= and ^= corresponding to the compound assignment version of the boolean logical & and ^ respectively. In other words, for boolean b1, b2, these …