Re: srfi1 patch

[Per Bothner <per at bothner dot com>]

Chris Dean wrote:

> Below is a patch for srfi1.scm to make all the functions accept very
> large lists.  We do this by constructing the functions so that Kawa can
> eliminate the tail calls and compile it down to purely iterative code.
>
> Comments welcome.

Checked this in with two trivial tweaks:
(1) Made %cars+cdrs/pair private
(2) Commented-out old implementation of partition!
using #|...|#, mainly to make it easier to bring it
back, if/when Kawa handles mutually tail-recursive
functions (in --no-full-tailcalls mode).

(It shouldn't be that difficult to optimize scan-in/scan-out
in partition!.  Each is just a "label" in the code, and the
tail-calls are jumps to the labels.  We would need to write
an analysis phase to determine when inlining is possible,
and generalize the existing tail-calling framework.)

I haven't gone through the patch line-by-line, to
see if all the algorithms are correct.  That would take
a bit of work, thouh it would probably be a good idea for
for someone else wants to double-check this code.
--
	--Per Bothner
per@bothner.com   http://per.bothner.com/