const by default.

[David Medlock]

clayasaurus wrote:

> Dave wrote:
> 
>> Ok, I know 'const' has been beaten to death in previous threads...
>>
>> However, one thing that I've not seen beaten to death is 'const by 
>> default'.
>>
>> In the following post, there's a link to comp.lang.c++.moderated where 
>> Walter puts forward some very good arguments regarding what's wrong 
>> with C++ (type modifier) const:
>>
>> http://www.digitalmars.com/drn-bin/wwwnews?digitalmars.D/39437
>>
>> In that thread, Walter mentions that he should have made const the 
>> default. Every subsequent post agreed with not one dissenter.
>>
>> Walter, what exactly do you have in mind? Only reference types? 
>> Default const for everything? Everything but function local variables? 
>> Or function return types and function parameters only?
>>
>> If some type of 'const by default' was implemented, it could have big 
>> consequences for Phobos. As Phobos is 'officially' supported and 
>> distributed w/ the compiler, it is the only thing that has to be 
>> changed along with the compiler.
>>
>> I'd say:
>> - add the 'mutable' keyword in v0.163
>> - let the community start modifying Phobos.
>> - add a "warn on non-mutable" switch to the compiler by v0.167 (that 
>> way Walter could implement all of the logic, and later cutover by 
>> removing the switch and making those errors instead of warnings).
>> - let the community test Phobos using the new warning switch
>> - 'cutover' when Phobos is done.
>>
>> I think the "too much water under the bridge" problem from Walter's 
>> standpoint is that he can't count on anyone else but himself making 
>> the changes to Phobos, and he simply doesn't have the time.
>>
>> I would gladly volunteer for a few of the Phobos modules but I don't 
>> have the time nor enough explicit knowledge of Phobos to lead the 
>> effort efficiently. If we could just get the 'mutable' keyword in 
>> there, then we could start a Dsource project and get "promises" from 
>> people in the community to do the work.
>>
>> Just some thoughts on the matter...
>>
>> Thanks,
>>
>> - Dave
> 
> 
> I wasn't necessarily supporting it, but if all the D experts think it is 
> a good idea after having a long conversation about it in the newsgroups, 
> then I wouldn't mind making changes.

FYI: I posted my thoughts in D.learn under :
"so what exactly is const supposed to mean?"

I should have posted here...oh well.