On 11/01/2013 12:26 AM, deadalnix wrote:
I think you take it the wrong way. Weak purity have some guarantee in
itself, like you know it won't reach shared data
I assume you mean mutable shared data.
unless you pass them explicitly, do not touch anything static,
Unless you pass it in explicitly.
etc . . .
Consider this:
shared static int x;
auto bar(){
class S{
shared(int)* p;
this(shared(int)* p){ this.p=p; }
int member(int y)pure{
return *p=y;
}
}
auto s=new S(&x);
return &s.member;
}
/+
auto bar_prime(){ // does the same thing. (but is rejected by DMD)
return (y)pure=x=y;
}+/
auto foo(int delegate(int)pure dg, int x)pure{
return dg(x);
}
void main(){
auto a=bar(); // note: a is pure
assert(x==0);
foo(a,2); // note: foo is weakly pure
assert(x==2);
foo(a,3);
assert(x==3);
}
