monarch_dodra:
*as* a matter of fact, that's how gcc does it for C++://---- int main() { int i = 0; ++i = ++i; assert(i == 2); //passes } //---- Left to right First, evaluate lhs: i has the value 1. then evaluate rhs, which will now have the value 2. assign 2 to i. * i == 2 * right to left: First, evalutate rhs: i has the value 1, an rhs 1. Evaluate lhs: i is now 2. But then assign rhs (1) to lhs. * i == 1 *So yeah, left to right evaluation is completely coherent, and a valid scheme.
I think the results of your code is not defined by the C++ standard, so in practice writing that code is a programmer's mistake. And it's a mistake to design a modern programming language that accepts code that gives undefined results. To be considered a grown up language D needs define only one semantics, or forbid code like that.
Evaluation order, even when defined, remains obscure once associative operations come into play, and still bite you in the ass anyways,
Even when the programmer isn't able to know what the result will be, it's essential for the D code to give the same result on all CPUs and on all compilers.
Bye, bearophile
