Re: forking builtins

[Alan Watson <alan@oldp.astro.wisc.edu>]

Of the suggestions I have seen so far, Malte's `line is clearly the
suggestion most in line with the rc philosophy.  However, it isn't
going to satisfy the performance demands (needs?) of many people.

At first glance a builtin read will be no faster than line because of
the way rc handles the redirection of builtins.  However, all one needs
to do is the following:

	exec <file
	while (read LINE) {
		...
	}

The same trick can be used with whatis -s.

The only impediment is choice of a fd on which to save stdin/stdout.
Anyone for adding $newfd to rc?

I can support the following course of action:

(a) add Malte's builtin line and rewrite UNIX so that fork is fast.

(b) add builtin read and rewrite rc's redirection on builtins.

(c) add builtin read and add $newfd to allow stdin/stdout to be safely moved.

(d) doing nothing rather than doing a half-baked job.

I favour (c), as it seems the most return for the least effort, but I
appreciate the attraction of (d).  rc is about as perfect as one could
hope, and meddling with near perfection is dangerous.

And, yes, a hypothetical read MUST do IFS splitting but should only
take one argument -- we have lists, let's use them.  The only question
is whether it should also allow one to specify the character which
terminates a record (IRT -- internal record terminator?).  I will even
promise to write a version which does this before the end of October.

And now, back to work.

Alan.