It would be very helpful if the assembler could output the assembled file to STDOUT, and read the assembly file from STDIN. Is there any possibility that this feature could be added?
See SF #760877 (and its duplicate SF #1705185) for supporting stdin.
Note that this requires buffering stdin in pass 1 (see SF #897003).
As for stdout -- that doesn't work, since there is no guarantee that all
of the output bytes get written in increasing order, or only once.