Store mutable indirections in immutable data with this one weird trick!

[Paul Backus]

On Saturday, 13 November 2021 at 14:35:36 UTC, Imperatorn wrote:
> On Saturday, 13 November 2021 at 14:32:15 UTC, Paul Backus 
> wrote:
>> On Saturday, 13 November 2021 at 13:11:05 UTC, Timon Gehr 
>> wrote:
>>> [...]
>>
>> In a language where valid programs cannot distinguish between 
>> different pointers to the same value, or observe the side 
>> effects of memory allocation, it is natural to define `pure` 
>> such that it allows memory allocation.
>>
>> [...]
>
> Many use the "compromise edition" to pure, I think it's ok. 
> Pure in that sense is just same out for a given in, doesn't 
> matter what the function does inside.

[`pureMalloc`][1] does not return the same output for a given 
input.

[1]: https://druntime.dpldocs.info/core.memory.pureMalloc.html