On Thu, 23 Sep 2010 16:35:23 -0400, Tomek Sowiński <j...@ask.me> wrote:
On topic: this means a pure function can take a reference to data that
can be mutated by
someone else. So we're giving up on the "can parallelize with no
dataraces" guarantee on
pure functions?
In short, No. In long; the proposal is for pure functions become broken up
into two groups (weak and strong) based on their function signatures. This
division is internal to the compiler, and isn't expressed in the language
in any way. Strongly-pure functions provide all the guarantees that pure
does today and can be automatically parallelized or cached without
consequence. Weakly-pure functions, don't provide either of these
guarantees, but allow a much larger number of functions to be
strongly-pure. In order to guarantee a function is strongly pure, one
would have to declare all its inputs immutable or use an appropriate
template constraint.
