Implementing Pure Functions

[Walter Bright]

On 6/16/2011 6:29 AM, Don wrote:
> bearophile wrote:
>> Walter:
>>
>>> Thanks to Andrei Alexandrescu, Brad Roberts, David Held, and Bartosz Milewski
>>> for their helpful comments and corrections on this post.<
>>
>> *pulls Walter's ears* You have forgotten who has found this problem :-)
>
> So have I. It was mentioned at the start of 2008 with respect to pure, but the
> same problem was mentioned with regard to CTFE much earlier, in 2006 I think. I
> think Daniel Keep was the first to mention it.

The acknowledgments did not attempt to credit where the idea came from, just the 
people who made comments on a draft of that post.

This thread is particularly relevant:

http://www.digitalmars.com/d/archives/digitalmars/D/Temporarily_disable_all_purity_for_debug_prints_134460.html

As for the problem, which is doing I/O in a pure function, that goes back decades.