On Monday, 23 November 2015 at 10:28:53 UTC, thedeemon wrote:
On Sunday, 22 November 2015 at 18:47:34 UTC, visitor wrote:
What is the reason for using pointers (alias pointerOf(T) = T*
etc...)
it works without ! what am i missing ?
What and how exactly works without?
My original solution remembers in the constructor addresses of
variables to fill, then does the filling in opAssign operator,
so I needed a way to store the references and used pointers for
that.
yes, but you are using ref : "auto let(Ts...)(ref Ts vars)"
so vars are changed, no need to store anything, no?
i was wondering if there is some subtleties or efficiency reasons
for using pointers
this work fine with your unittest :
auto let(Ts...)(ref Ts vars) {
struct Let
{
void opAssign( Tuple!Ts xs ) {
foreach(i, t; Ts)
vars[i] = xs[i];
}
static if (sameTypes!Ts) {
import std.conv : text;
void opAssign(Ts[0][] xs) { // redundant but more
effective
enforce(xs.length == Ts.length, "let (...) = ...:
array must have " ~ Ts.length.text ~ " elements.");
foreach(i, t; Ts)
vars[i] = xs[i];
}
void opAssign(R)(R xs) if (isInputRange!R &&
is(ElementType!R == Ts[0])) {
static if (hasLength!R) {
enforce(xs.length >= Ts.length, "let (...) =
...: range must have at least " ~ Ts.length.text ~ " elements.");
}
foreach(i, t; Ts) {
enforce(!xs.empty, "let (...) = ...: range
must have at least " ~ Ts.length.text ~ " elements.");
vars[i] = xs.front;
xs.popFront();
}
}
void opIndexAssign(R)(R xs) if (isInputRange!R &&
is(ElementType!R == Ts[0])) {
foreach(i, t; Ts) {
if(xs.empty) return;
vars[i] = xs.front;
xs.popFront();
}
}
}
}
return Let();
}
