On 08/26/2016 09:51 PM, Patrick Schluter wrote:
On Friday, 26 August 2016 at 14:03:13 UTC, Meta wrote:
[...]
class Test
{
int n;
void setN(int val) pure
{
n = val;
}
int getN() const pure
{
return n;
}
}
getN() is not pure, simple as that (and an ideal compiler should
complain in that case). A function is pure if it depends only of the
state passed as parameter. If it touches memory that is set outside its
scope it is NOT PURE!!!
You can rewrite that code like this:
----
class Test {/* ... as before but without getN ... */}
int getN(const Test test) pure { return test.n; }
----
Is getN pure now? It only touches memory via the parameter.
For methods we can think of `this` as a hidden parameter. If the method
is tagged `const` or `immutable`, it's really that hidden parameter that
is being qualified.
