Re: request for review: Doing direct file I/O in Emacs Lisp

[John Wiegley <johnw@gnu.org>]

Richard Stallman <rms@gnu.org> writes:

> I deliberately decided not to add this feature to Emacs because it
> tends to lead to a demand for lots more features to "make it
> complete", and that ultimately leads to a lot more complexity.  For
> most purposes, reading files into buffers is just as good.
>
> Why do you think we should add this feature now?

I understand that rationale, but in this case Eshell has a crying need
for being able to directly write to files.  It makes output
redirection thousands of times faster, and also makes it possible to
output to device files and named pipes.

At present, output redirection is so slow that I have to spawn zsh to
run commands which generate over 10,000 lines of output (such as
debugging printfs).  I have always deplored this, since Eshell
satisfies me in almost every other respect.

I don't mind even if we use a custom interface, strictly for Eshell's
needs; but the file handle API seemed so simple, I thought others
might be interested in it too.

John