Porting D 1.0 code to 2.0, 'const' -> 'invariant'

[Robert Fraser]

Sean Kelly wrote:
> I know this issue has been discussed to death, but I'd like to once
> again question the rationale behind changing the meaning of the 'const'
> keyword between 1.0 and 2.0, given that the choice of keywords for const
> features in 2.0 seems completely arbitrary.
> 
> In D 1.0, 'const' is essentially the same as 'invariant' in D 2.0.  It's
> true that 'const' works just as well for the average situation in D 2.0,
> but what if I have a ton of constants in a D 1.0 library that I want to
> work the same way in D 2.0?  ie. in D 1.0 the 'const' label means I can
> use the value without synchronization for multithreaded programming,
> etc.  In D 2.0, this role is filled by 'invariant' and 'const' has been
> weakened to mean "read-only view," which is not at all the same thing.
> 
> I suppose what I'm asking is how I should go about making a library
> maximally cross-compatible with D 1.0 and 2.0, given the changed meaning
> of 'const'?
> 
> 
> Sean

Mixins.