On Monday, 12 November 2012 at 23:38:43 UTC, luka8088 wrote:
What about making this a default behavior and introducing a new
keyword if the function wants to modify the argument but it is
not ref (pass by value) ? The reason I think that this should
be a default behavior because not many functions actually
modify their arguments and so it leaves a lot of space for
optimization.
For example:
void f (int x, val int y, ref int z) {
x = 1; // x is not copied
// compiler throws an error, x is not passed by value
// and therefor could not / should not be changed
y = 2; // ok, y is copied
z = 3; // ok, z is a reference
}
Your proposal isn't really related to this thread's topic, but I
understand what you mean (although your code comments distract me
a bit):
void f(const int x, int y, ref int z); =>
void f(int x, val/mutable int y, ref int z);
I use const/in ;) parameters a lot in my code too to prevent
accidental modifications, so my function signatures may be more
compact by treating normal pass-by-value parameters as const if
not denoted with a special keyword. I guess it wouldn't be very
important for optimization though because I'd expect the
optimizer to detect unchanged parameters. Anyway, your proposal
would completely break existing code.
