Maybe D is right about GC after all !

[Walter Bright]

On 12/27/2017 8:38 AM, Laeeth Isharc wrote:
> On Wednesday, 27 December 2017 at 07:44:30 UTC, Walter Bright wrote:
>> On 12/26/2017 4:18 AM, Russel Winder wrote:
>>> All of which brings us full circle: when it comes to programming
>>> languages and software development, it is all about advocacy,
>>> prejudice, and belief, there is very, very little science happening –
>>> and most of the science that is happening is in the psychology of
>>> programming, about which most developers of programming languages know
>>> nothing.
>>
>> If you're hinting that I know nothing about the topic, you're mistaken :-)
>>
>> A fair amount of D's design is based on psychology.
> 
> I'd love to hear more about this sometime.

One fun example is our quest to find the right keyword for read only data. A 
long list of words were examined, like readonly, invariant, etc. Some had 
various baggage connotations, some weren't clear what they meant.

We found ourselves constantly saying things like: "readonly means immutable", 
"invariant means immutable", etc. Finally we got hit with a clue-by-four - 
everyone understood what "immutable" meant, so why not just use "immutable"?

Pure psychology, and nothing to do with computer science.

---

Another is it is known that people have cognitive problems with negation. It 
often just does not register in the mind. This is why version statements in D do 
not have negation. It more or less forces one to think of using positive version 
identifiers:

     version (hasFeature) { ... }

as opposed to:

     version (!hasFeature) { ... }

or even worse (yes I've seen it):

     version (!doesNotHaveFeature) { ... } // :-(

In order to do negation, one must resort to:

     version (hasFeature) { } else { ... }

Having converted a lot of C code to D and dealing with things like:

     #if !__OSX__
        ... call X ...

having to redesign the case to use positive features:

     version (hasX)
        ... call X ...

makes the code a lot more readable. It's worth it.

The psychological cognitive issues around negation are known, but I rarely see 
deliberate efforts by programmers to deal with that issue. D kinda forces it, 
and I get resistance to it, but it is worthwhile to push it because the results 
are worth it.