Re: Declaring constant references in struct members
On Thursday, 16 February 2017 at 01:05:58 UTC, David Zhang wrote: Is there a similar mechanism for one struct holding another? You'd have to make the member a pointer to the struct. immutable(B)* b;
Re: Declaring constant references in struct members
On Thursday, 16 February 2017 at 00:49:45 UTC, Adam D. Ruppe wrote: On Thursday, 16 February 2017 at 00:43:30 UTC, David Zhang wrote: struct S { O object; } import std.typecons; Rebindable!O object; http://dpldocs.info/experimental-docs/std.typecons.Rebindable.html Is there a similar mechanism for one struct holding another? Otherwise, you get a cannot modify X with immutable members error. eg: struct A { B b; } struct B { const size_t something; } A a = A(B(16)); //attempt to replace a.b with new B a.b = B(32); //error: cannot modify struct a.b B with immutable members
Re: Declaring constant references in struct members
On Thu, Feb 16, 2017 at 12:43:30AM +, David Zhang via Digitalmars-d-learn wrote: > Hi, > > Say I have a struct S that holds a reference to an object O. Is there > a way to express that I want to be able to change the reference, but > not what the reference points to? Thanks. > > struct S { > O object; > } > > class O { > size_t things. > } Maybe have a look at std.typecons.Rebindable? T -- What do you call optometrist jokes? Vitreous humor.
Re: Declaring constant references in struct members
On Thursday, 16 February 2017 at 00:43:30 UTC, David Zhang wrote: struct S { O object; } import std.typecons; Rebindable!O object; http://dpldocs.info/experimental-docs/std.typecons.Rebindable.html