On Mon, 9 Nov 2009, Daniel Bünzli wrote:

> Tuples and records are represented the same way. However when it comes
> to records with only floats fields we get a special unboxed
> representation.
>
> Why don't we get that for tuples of floats only ?

Because tuples are generic data types.  Access to records and arrays are 
special cased- in the record case, because the compiler knows the type of 
the record, in the array case because array access is via C code which 
handles the special case.  But the compiler needs to be able to compile 
code with generic tuple accesses, like:

let third_of_four (_, _, x, _) -> x;;

Fixing this would require a major rearchitecting and rewrite of not only 
the compiler, but also the garbage collector, the run time, and all the C 
bindings that have been written.

Brian