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| Posted by Cecil Ward in reply to Atila Neves | PermalinkReply |
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Cecil Ward
Posted in reply to Atila Neves
| On Friday, 29 September 2017 at 13:07:32 UTC, Atila Neves wrote:
> auto modifiable = foo();
> {
> const nonModifiable = modifiable;
> //...
> }
I had already thought about using two names.
I don’t think that using a kind of ‘const-alias’ mechanism (or ‘const reference’, in the C++ var& sense) would be a good idea at all. By this I mean something where a modifiable variable has two names, only of of them permitting write access. The reason why this wouldn’t be good enough is that there would be nothing much stopping me from forgetting what I’m doing and going back to using the wrong name at some point, without any warnings. Slight mitigation would be if the original declaration was something like myvar_writeable and the const alias for it was called simply myvar, so that the default brain-free form would be the safe one and you would have to go out of your way to get write access. It still wouldn’t be that strong though.
Iirc you get told off if you block access to variables by using ‘shadowing’, declaring an exactly matching name using an alias declaration in a normal basic block scope. (I suspect you can do so inside function bodies, I don’t think d moans about you blocking access to matching variables that are in global or outer, non-global, non-local scopes if you write ‘shadowing’ local variable declarations - not sure.) Anyway, couldn’t use that either and it’s no way usable enough for me.
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