Binary comprehensions

Bjorn Gustavsson <>
Wed Aug 18 09:38:02 CEST 2004

I, too, find the concept of binary comprehensions
interesting and worthwhile.

However, we will probably not have time to even think
about it for the R11 release.

There will some minor performance improvements in the
bit syntax in R10, and there might be more in R11 (as well
as the addition of some minor features).

Thomas Lindgren <> writes:

> Yes. The trade-off is between speed and specificity.
> For example, one could restrict such hypothetical
> notation so that it is compilable into a C loop or
> less. The restrictions might then be severe, and
> perhaps not very intuitive. [Should we permit GC in
> the middle? If so, what about having uninitialized
> preallocated memory in the heap?] Or one could go in
> the other direction and be very permissive, though the
> gains vs using lists might then be small. 

Another way is to make the compiler smarter, so that it
does more aggressive optimization whenever possible, and
falls back to slower code when not possible.

To some extent, we do that alreday in the current bit syntax
implementation (especially in R10B).

> One option could be to revisit the "research binary
> syntax", which included a lot more features than the
> binary syntax we have now. 

We might add some more features from the "research syntax"
to R11. 

Björn Gustavsson, Erlang/OTP, Ericsson AB

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