How do I use CTFE to generate an immutable associative array at compile time?

[H. S. Teoh via Digitalmars-d-learn]

On Wed, Feb 22, 2017 at 06:17:14PM +0000, Stefan Koch via Digitalmars-d-learn wrote:
> On Wednesday, 22 February 2017 at 17:05:17 UTC, H. S. Teoh wrote:
> > On Wed, Feb 22, 2017 at 04:08:45PM +0000, Stefan Koch via
> > Digitalmars-d-learn wrote:
> > > [...]
> > 
> > I'm not sure it's that simple.  Just because AA's become CTFEable
> > doesn't mean they will automatically be convertible to object code
> > in the executable that allows runtime AA lookups.  For instance, a
> > CTFE pointer will have a value that has no correspondence with the
> > object code in the executable, and neither will memory allocated
> > during CTFE have any correspondence with the emitted object code
> > (because this memory is allocated in the compiler, not in the object
> > code). So if the CTFE AA implementation allocates nodes for storing
> > key/value pairs, they will only exist in the CTFE engine, and
> > pointers to them will only make sense within the CTFE engine.  In
> > order to make them work in the executable (so that you can do AA
> > lookups to these computed nodes at runtime), you will need to
> > somehow map them to object code.  Just because AA's become CTFEable
> > will not automatically solve this for you.
> > 
> > [...]
> 
> The CTFE allocated memory can be copied into the object file verbatim
> because the structure is the same. Pointers are easy to fix up as
> well, because by definition the have to point to static data that will
> be in the object file.

This will fail for cross-compilation. Unless you mean that the new CTFE
engine is emulating the target machine directly?


T

-- 
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