On 08/21/2011 09:10 PM, Don wrote:
bearophile wrote:
Sean Eskapp:
Oh, I see, thanks! This isn't documented in the function documentation!
D purity implementation looks like a simple thing, but it's not
simple, it has several parts that in the last months have be added to
the language and compiler, and we are not done yet, there are few more
things to add (like implicit conversion to immutable of the results of
strongly pure functions). It will need several book pages to document
all such necessary design details.
Bye,
bearophile
It is actually very simple: a function marked as 'pure' is not allowed
to explicitly access any static variables.
Everything else is just compiler optimisation, and the programmer
shouldn't need to worry about it.
It can be of value to know that a function is pure as in mathematics if
it is strongly pure, but can have restricted side-effects if it is
weakly pure.
