On 03/12/2016 9:55 PM, dan wrote:
In c, you can have code like this:
static void wtest( void ) {
int f;
while ( ( f = some_val( ) ) ) {
printf(" our value is now: %d\n", f );
}
}
gcc compiles this without warning or error (at least if you use the
double parentheses to assure the compiler that you realize you are
testing an assignment, not a comparison).
I would like to do the same thing in d, something like this:
private void wtest( ) {
int f;
while ( ( f = some_val( ) ) ) {
writeln(" our value is now: ", f );
}
}
or even better:
private void wtest( ) {
while ( ( auto f = some_val( ) ) ) {
writeln(" our value is now: ", f );
}
}
This however does not work, and the gdc compiler says "assignment cannot
be used as a condition, perhaps == was meant?"
I don't absolutely have to do it this way, as i guess i could do 'while
(true) {...' and then break if the assignment returns zero.
But i really, really would like to use the idiom of assigning a value
from inside a while condition.
Is it possible to do this? Perhaps with extra braces or something, like
while ( {something here} ) { .... } ?
TIA for any pointers or advice.
dan
If you can use another compiler do so, gdc is on an old frontend/Phobos
now. I recommend ldc or you know the reference compiler dmd if
performance/platform isn't an issue (not that dmd can't produce decent
codegen).
This does compile:
int func() {
return 0;
}
void main() {
int x;
while((x = func()) != 0) {
}
}
