Issue 6169

bearophile bearophileHUGS at lycos.com
Thu Jun 16 19:06:46 PDT 2011


Pure functions in D keep producing new and new ideas. There are some purity-related ideas yet to be implemented, but (I think) accepted by Walter, like allowing an implicit cast to const of the result of a strongly pure function, or generating an error if you don't assign the result of a strongly pure function to a variable. And there is my not so much appreciated idea of the @transparent too (and maybe there are other ideas I don't remember at the moment).

A new idea has just appeared in Bugzilla, by Timon Gehr:
http://d.puremagic.com/issues/show_bug.cgi?id=6169

It asks to allow code like this too, where a pure function calls a impure one and assigns the result with enum:

int x = 10;
int foo(bool b) {
    if (b)
        x++;
    return 0;
}
pure void main() {
    enum y = foo(false);
}


After thinking some about it, I think it's acceptable. See my comment in the bug report for more info.

Bye,
bearophile


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