Subject: [clisp-list] Re: old issues: unicode & docs

From: Bruno Haible <[email-masked]>
Date: Mon May 10 10:58:02 2004

Sam wrote:
> Bruno,
> about 2 years ago I asked you these questions:
>
> 1. why does
>        (with-open-file (s "foo" :external-format charset:ascii) (read-line s))
> return a 32-bit and not an 8-bit string?

Because I haven't yet implemented all the possible optimizations that are in
my TODO list.

> 2. why does SPARC prevent HAVE_SMALL_SSTRING?

Does it? The ChangeLog mentions a patch dated from 2004-02-18 that supports
HAVE_SMALL_SSTRING on all kinds of platforms.

> 3. Why do built-in UCS-2 and iconv utf-16 treat odd-length byte arrays
>    differently?

I don't remember there's a good reason for either behaviour.

> 4. Are the porting instructions in unix/PLATFORMS up to date?

Mostly, yes. (But the "at most 4 GB" for 64-bit platforms is not true for
AMD64. There, clisp's imposed limit is currently 2^48 bytes, but could grow
to 2^56 bytes if there is need.)

>    Could you please add a section to doc/impbyte.xml on
>      "How to add new bytecode instructions"
>    (what to modify, what to watch out for, how to test performance
>    hits/improvements &c)

No, I can't. This is an area which requires thought, and cannot be handled in
a "how do I" style FAQ.

But what I can do, is to make exercises (of level >= 30 in Knuth's
convention) regarding things like that.

Exercise 1: Does it make sense to define a new bytecode instruction for
RESTART-CASE? Why? Why not?

Bruno