On Friday, 6 July 2018 at 15:44:28 UTC, Steven Schveighoffer
wrote:
I'm long overdue for an inout article...
I can point you at my talk from 2016:
https://www.youtube.com/watch?v=UTz55Lv9FwQ
Thanks, will definitely take a look when I get home.
I never really used 'pure' and just now found a use case with
immutable [1], i.e. to return unique objects from functions
which can be assigned to a mutable or immutable reference.
What other "use cases" or reasons to use 'pure' are there
(aside from compiler optimizations)?
The reason pure functions allow mutability changes is due to
the nature of what pure means semantically -- you have
guarantees that nothing else goes in or out, so it's possible
to deduce what is unique and what is not.
This is powerful to a human reader of a function as well!
Without seeing the insides, it tells you exactly what it can
and cannot affect, giving you more understanding of when it can
be used and when it can't. It helps write safer more tractable
code, IMO.
In the end, all these attributes are to help reason about large
code bases without having to read ALL the code.
Sounds like a good idea to always use it whenever possible. For
me as a kind of novice it takes time to understand the purpose
and meaning of each of those attributes. I guess I got one step
closer to understanding "Why pure?".
That leaves @nogc, @safe and @trusted :D. I feel the best way to
understand these idioms is to experience the "trouble" oneself. I
knew in some way what pure functions were from the spec, but I
didn't have an example at hand that made "non-usage" of pure
painful.
