mapfile module - avoiding $(...) in completion functions

["Andrej Borsenkow" <Andrej.Borsenkow@xxxxxxxxxxxxxx>]

>
> Since in the completion system we generally want to avoid the extra
> processes needed for $(...), we would use caching for the printer
> names there (and the function for the lp commands I just sent to
> zsh-workers does that). And we would also make this nicer by
> supporting the other mechanisms used throughout the completion system.
>

May be it was discussed already, but is not mapfile module alternative to
$(...)? We mostly need it to parse files content, as in $(</etc/printcap), and
in this case we could just as well mmap the file.

And where the "real" $(...) is needed, we cannot cache it anyway (process list
is an example).

Is there any system now-a-days without mmap support?

/andrej