Confused about const

Paul D. Anderson paul.d.removethis.anderson at
Sat Mar 20 10:33:16 PDT 2010

bearophile Wrote:

> Paul D. Anderson:
> > After further review, I now realize that the right way (for me) to do this is to add a .dup property.<
> Steven Schveighoffer has given you quite good answers.
> A dup is generally not enough, because what you dup can have other immutable references nested inside. Dup is not a deep copy.
> The summary of this topic is (until inout works) that if you can return a const value, then don't copy things. This is the preferred option, because one of the main purposes of const data is to not have to copy them.
> If you can't return a const, then don't mark the input values as const. The safety given by the not deep const of Java is only partial safety.
> Bye,
> bearophile

You're right that dup itself can have problems with pointers/references. My struct doesn't have 2nd-level references, so dup works fine for me.


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