I came upon realization that you can already create properties
accepting various operators in D, using a template mixin. The only
missing part is getting the value without a getter function.
struct Z
{
int value2Cache;
template Property()
{
int value;
void opAssign(int newValue) { value = newValue; value2Cache = value *
value; }
void opAddAssign(int otherValue) { value += otherValue; value2Cache =
value * value; }
int get() { return value; }
}
mixin Property property;
}
int main(char[][] m)
{
Z z;
z.property = 1;
z.property += 1;
assert(z.property.get == 2);
assert(z.value2Cache == 4);
return 0;
}
Perhaps "alias value this;" could do the trick, but alas it only works
with structs and classes currently, not templates, as this case
demonstrate:
struct Z
{
int value2Cache;
template Property()
{
int value;
alias value this;
void opAssign(int newValue) { value = newValue;
value2Cache = value * value; }
void opAddAssign(int otherValue) { value += otherValue;
value2Cache = value * value; }
}
mixin Property property;
}
int main(char[][] m)
{
Z z;
z.property = 1;
z.property += 1;
assert(z.property == 2);
assert(z.value2Cache == 4);
return 0;
}
property.d(24): Error: expression has no value
property.d(8): Error: alias this alias this can only appear in struct
or class declaration, not main
property.d(16): Error: mixin property.main.Property!() error instantiating
--
Michel Fortin
[email protected]
http://michelf.com/
