The point of const, scope, and other attributes

[Fry]

On Wednesday, 11 May 2022 at 18:18:18 UTC, Walter Bright wrote:
> On 5/11/2022 3:48 AM, IGotD- wrote:
>> C# went the other way, no const parameters at all. Maybe 
>> because it doesn't make much sense because there is a lot of 
>> runtime violations of const underneath. Anyway, I like the C# 
>> aproach better because it is simpler for the programmer.
>
> It's not simpler for someone trying to read the code. Function 
> documentation almost never says "by the way, this `getValue` 
> function also tweaks the database."

Good documentation will. Really const doesn't help with making 
code more readable either. I avoided using const in D cause it 
just got in the way more than it was helping. The most useful 
feature for const to exist in C++ was that it allows you to do 
`const T&` which will allow you to pass anything to that 
function, rvalue or lvalue without making a copy. D doesn't do 
this though. I think C# did the right call in excluding it, it 
would have just added complexity without much benefit.

>> Another problem is that all this badging tend to get out of 
>> hand and it breeds more badges until it doesn't mean anything. 
>> For example what will happen if D adds a mutable attribute?
>
> It already has a mutable attribute - nothing!

I think he means a mutable attribute that allows you to modify a 
value even if the object is const. Like C++'s mutable.