Re: [CM] R7RS support
Thanks Iain, great observations and info. Yes, we’ve read s7.html many
times and will continue to do so. There’s a lot of great info there!
(We’ve found many of the included scm files are also good sources
too.)
FYI, we’re looking at adopting R7RS more as a future-proofing strategy
than “we need every single feature and exact compatibility”. Having
successfully shipped some basic functionality on iOS as a
proof-of-concept, we’re stepping back and tweaking our development
environment & tooling. Currently we’re attempting to run our code with
Guile and its R7RS libraries, in part to take advantage of the nice
tooling in Geiser in Emacs. The goal is to have our integration & unit
tests run in both s7 and Guile (and/or other R7RS-compatible Schemes)
with minimal shim layers. If we can keep the ease of embedding, small
size and performance of s7 for mobile while doing this, then dare I say
we’ll have our cake and eat it too? :)
Cheers, Michael
On 17 Jan 2022, at 23:52, Iain Duncan wrote:
Hi Rudolf, Bill would be the person to address this better than me,
but I
think the Egghead team should read through the s7.html page pretty
closely
to see if s7 is a good fit. It's pretty clear in there that there is
*limited* R7RS compatibility, but that s7 is not R7RS and nor is that
a
stated goal. For example, s7 does not do macros with syntax-case or
syntax-rules, but uses CL style macros. If R7RS is what you need, you
might
be better off with an implementation that makes that a goal, such as
Chibi.
I use s7 embedded in audio programs, which shares a fair bit of domain
space with games, and I personally chose s7 because the performance
and
ease of embedding made up for that, but YMMV!
HTH
iain
On Mon, Jan 17, 2022 at 7:36 AM Rudolf Adamkovič
wrote:
Hi there!
At Egghead Games, we would like to use Scheme for in-app scripting.
We
wired up s7 and SQLite to kick things off, but s7 support for R7RS
does
not seem to work. Below, I include some examples to illustrate my
point.
A basic example from the R7RS standard, page 54, …
(with-exception-handler
(lambda (x)
(display "something went wrong\n"))
(lambda ()
(+ 1 (raise ’an-error
… results in:
Error: catch error handler should accept two arguments: #(x)>
The simplest library …
(load "r7rs.scm")
(define-library (some lib)
(export some-proc)
(import (scheme base)
(scheme r5rs))
(begin
(define (some-proc x)
(display x
… results in:
Error: symbol->value first argument, {gensym}-1, is a macro but
should
be a symbol (define-macro ({gensym}-1 . names)...
We picked s7 because the website says …
I believe it is compatible with r5rs and r7r
… but per a quick grep, there seem to exist no tests for
define-library
or with-exception-handler.
Any ideas?
Rudy
--
"Logic is a science of the necessary laws of thought, without which
no
employment of the understanding and the reason takes place." --
Immanuel
Kant, 1785
Rudolf Adamkovič [he/him]
Studenohorská 25
84103 Bratislava
Slovakia
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Re: [CM] TeXmacs & S7
Do I understand you correclty that the patch I implemented break some assumption of your code In general, yes. I'd have to read through the code -- I glanced at it a few months ago, but can't remember any details, except that it struck me as written for Guile 1.8? and perhaps awkward for s7 (something about modules?). ___ Cmdist mailing list Cmdist@ccrma.stanford.edu https://cm-mail.stanford.edu/mailman/listinfo/cmdist
Re: [CM] TeXmacs & S7
Dear Bill, thanks for the remarks. Do I understand you correclty that the patch I implemented break some assumption of your code. Is there a way to be sure I'm not introducing any bug? Best, Max > On 17. Jan 2022, at 21:13, b...@ccrma.stanford.edu > wrote: > > Currently, s7's optimizer sometimes depends on the position of the variables > in environments, so your change is only safe if the optimizer gives up. > Since the order matters, a hash-table lookup is unlikely to work without > some serious overhead. Most environments have only a handful of locals, and > a small linear search is faster than a hash-table lookup (and the search is > unnecessary if the variables have unique names). > ___ Cmdist mailing list Cmdist@ccrma.stanford.edu https://cm-mail.stanford.edu/mailman/listinfo/cmdist
Re: [CM] TeXmacs & S7
Environments come and go at an amazing pace That's why I suggest to only build a hash table only after a certain number of accesses. -E ___ Cmdist mailing list Cmdist@ccrma.stanford.edu https://cm-mail.stanford.edu/mailman/listinfo/cmdist
Re: [CM] TeXmacs & S7
Another idea is inline caching... And probably better than a hash-table, but it's yet another layer in an already complicated process. I might try that just to see what happens -- thanks for the suggestion! ___ Cmdist mailing list Cmdist@ccrma.stanford.edu https://cm-mail.stanford.edu/mailman/listinfo/cmdist
Re: [CM] TeXmacs & S7
Why not maintain a hash table whose values are offsets into the flat environment? Then it's a cheap branch or two on lookup to see: 1) is there a hash table; 2) should I build one (is the env big enough, and have there been enough lookups). I call that serious overhead. Environments come and go at an amazing pace. Most lookups are already immediate (do not involve a search). In some cases (non-recursive, safe functions), I can save the environment and reuse it, so some analysis might be acceptable. I doubt that applies here because apparently the optimizer already threw up its hands. (Environments in s7 are very dynamic -- I do not currently try to keep the env's length stored somewhere, and to get it is nearly as bad as a linear search). ___ Cmdist mailing list Cmdist@ccrma.stanford.edu https://cm-mail.stanford.edu/mailman/listinfo/cmdist
Re: [CM] TeXmacs & S7
Another idea is inline caching... On Mon, 17 Jan 2022, Elijah Stone wrote: On Mon, 17 Jan 2022, b...@ccrma.stanford.edu wrote: Currently, s7's optimizer sometimes depends on the position of the variables in environments, so your change is only safe if the optimizer gives up. Since the order matters, a hash-table lookup is unlikely to work without some serious overhead. Most environments have only a handful of locals, and a small linear search is faster than a hash-table lookup (and the search is unnecessary if the variables have unique names). Why not maintain a hash table whose values are offsets into the flat environment? Then it's a cheap branch or two on lookup to see: 1) is there a hash table; 2) should I build one (is the env big enough, and have there been enough lookups). -E ___ Cmdist mailing list Cmdist@ccrma.stanford.edu https://cm-mail.stanford.edu/mailman/listinfo/cmdist ___ Cmdist mailing list Cmdist@ccrma.stanford.edu https://cm-mail.stanford.edu/mailman/listinfo/cmdist
Re: [CM] TeXmacs & S7
On Mon, 17 Jan 2022, b...@ccrma.stanford.edu wrote: Currently, s7's optimizer sometimes depends on the position of the variables in environments, so your change is only safe if the optimizer gives up. Since the order matters, a hash-table lookup is unlikely to work without some serious overhead. Most environments have only a handful of locals, and a small linear search is faster than a hash-table lookup (and the search is unnecessary if the variables have unique names). Why not maintain a hash table whose values are offsets into the flat environment? Then it's a cheap branch or two on lookup to see: 1) is there a hash table; 2) should I build one (is the env big enough, and have there been enough lookups). -E ___ Cmdist mailing list Cmdist@ccrma.stanford.edu https://cm-mail.stanford.edu/mailman/listinfo/cmdist
Re: [CM] TeXmacs & S7
Thanks for the observations -- I'm glad s7 has worked out reasonably well. On your questions: 1) would it be possible to have lookup_from implemented via some hash table...? Alternatively, can our patch be made into the official version? Currently, s7's optimizer sometimes depends on the position of the variables in environments, so your change is only safe if the optimizer gives up. Since the order matters, a hash-table lookup is unlikely to work without some serious overhead. Most environments have only a handful of locals, and a small linear search is faster than a hash-table lookup (and the search is unnecessary if the variables have unique names). I think your situation is an unusual case: you apparently have more than 100 local variables in an environment, and the ones you want do not have unique names. I wonder if you could use a hash-table for the local variables. Or (kinda ugly) look at the code and place the most used variables so they are at the front of the list of slots (I can't immediately remember whether that means first or last in the list of let variables). 2) Suggestions to explain the high memory usage? (*s7* 'memory-usage) can tell you what is taking up the space. If that doesn't help, you might be able to tune the GC with the gc-related fields in *s7*. ___ Cmdist mailing list Cmdist@ccrma.stanford.edu https://cm-mail.stanford.edu/mailman/listinfo/cmdist
[CM] TeXmacs & S7
Dear all,
integration of S7 in the TeXmacs document editor (www.texmacs.org) has been
quite successful so far. You can grab the associated development branch here at
github
https://github.com/texmacs/texmacs/tree/wip_s7
you will need Qt 4/5 and some other libraries to compile it. Some preliminary
tests (which I think I've already posted on this list) and comments on the
intergation of various kinds of schemes in TeXmacs are here
https://texmacs.github.io/notes/docs/scheming.html
Speed is great, much better than guile 1.8 (our standard scheme implementation)
for the most part. Some users reported slowing down in some tasks (like
converting to LaTeX) but I still haven't measured this.
We use a mostly unmodified version of S7 where only the patch attached below is
used. It modifies the way lookup_from works, by putting at the beginning of the
symbol list symbols which are way back and are looked upon. For us this is a
game-changer : without it TeXmacs/S7 is unusable. We rely on scheme on many
places, in particular the menus and the UI is dynamically generated from scheme
descriptions at each keypress, in response to changes of the position of the
cursor in the document (which affects which element the user is current
focussing and therefore which UI elements are appropriate to show).
We experience problems with the memory footprint of the program. TeXmacs/Guile
uses usually ~500MB on my Mac while TeXmacs/S7 goes slowly up to ~1GB and some
users saw also ~2GB of memory footprint.
I have a couple of requests for the developer(s?):
1) would it be possible to have loopup_from implemented via some hash table or
some speedier lookup? It would be great to shave some more performances out of
this. Alternatively, can our patch be made into the official version? (or maybe
some improved version of it)
2) Suggestions to explain the high memory usage? Do somebody else also
experience these problems?
Thanks for this great program.
Best regards,
Massimiliano Gubinelli
--
diff --git a/src/src/Scheme/S7/s7.c b/src/src/Scheme/S7/s7.c
index ed5965591..f0c3488dd 100644
--- a/src/src/Scheme/S7/s7.c
+++ b/src/src/Scheme/S7/s7.c
@@ -10124,10 +10124,20 @@ static inline s7_pointer lookup_from(s7_scheme *sc,
const s7_pointer symbol, s7_
}
for (; is_let(e); e = let_outlet(e))
{
- s7_pointer y;
- for (y = let_slots(e); tis_slot(y); y = next_slot(y))
- if (slot_symbol(y) == symbol)
- return(slot_value(y));
+ s7_pointer y, py;
+ int steps = 0;
+ for (y = let_slots(e); tis_slot(y); py = y, y = next_slot(y), steps++)
+ if (slot_symbol(y) == symbol) {
+/* (TeXmacs) We try to bring back symbols which are used frequently to the
+ beginning of the list. This improves the lookup in TeXmacs.
+ The threshold is chosen heuristically.*/
+if (steps > 100) {
+ next_slot(py) = next_slot(y);
+ next_slot(y) = let_slots(e);
+ let_slots(e) = y;
+}
+return(slot_value(y));
+ }
}
if (is_slot(global_slot(symbol)))
return(slot_value(global_slot(symbol)));
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Re: [CM] R7RS support
The with-exception definition in r7rs.scm probably should be (define (with-exception-handler handler thunk) (catch #t thunk (lambda args (apply handler args The define-library code dates from the days (years ago) when s7's define-macro returned the symbol rather than the value. Also, I apparently missed the built-in library for r5rs names. For the latter add (apply define (symbol (object->string '(scheme r5rs))) (inlet) ()) For the former 295c296 < (cons 'export (symbol->value --- (cons 'export ;(symbol->value 297c298 < `(set! *export* (append ',names *export*)) --- `(set! *export* (append ',names *export*);) That is, symbol->value is probably not needed anymore. ___ Cmdist mailing list Cmdist@ccrma.stanford.edu https://cm-mail.stanford.edu/mailman/listinfo/cmdist
Re: [CM] R7RS support
Hi Rudolf, Bill would be the person to address this better than me, but I
think the Egghead team should read through the s7.html page pretty closely
to see if s7 is a good fit. It's pretty clear in there that there is
*limited* R7RS compatibility, but that s7 is not R7RS and nor is that a
stated goal. For example, s7 does not do macros with syntax-case or
syntax-rules, but uses CL style macros. If R7RS is what you need, you might
be better off with an implementation that makes that a goal, such as Chibi.
I use s7 embedded in audio programs, which shares a fair bit of domain
space with games, and I personally chose s7 because the performance and
ease of embedding made up for that, but YMMV!
HTH
iain
On Mon, Jan 17, 2022 at 7:36 AM Rudolf Adamkovič wrote:
> Hi there!
>
> At Egghead Games, we would like to use Scheme for in-app scripting. We
> wired up s7 and SQLite to kick things off, but s7 support for R7RS does
> not seem to work. Below, I include some examples to illustrate my
> point.
>
> A basic example from the R7RS standard, page 54, …
>
> (with-exception-handler
> (lambda (x)
> (display "something went wrong\n"))
> (lambda ()
> (+ 1 (raise ’an-error
>
> … results in:
>
> > Error: catch error handler should accept two arguments: #
>
> The simplest library …
>
> (load "r7rs.scm")
> (define-library (some lib)
> (export some-proc)
> (import (scheme base)
> (scheme r5rs))
> (begin
> (define (some-proc x)
> (display x
>
> … results in:
>
> > Error: symbol->value first argument, {gensym}-1, is a macro but should
> > be a symbol (define-macro ({gensym}-1 . names)...
>
> We picked s7 because the website says …
>
> > I believe it is compatible with r5rs and r7r
>
> … but per a quick grep, there seem to exist no tests for define-library
> or with-exception-handler.
>
> Any ideas?
>
> Rudy
> --
> "Logic is a science of the necessary laws of thought, without which no
> employment of the understanding and the reason takes place." -- Immanuel
> Kant, 1785
>
> Rudolf Adamkovič [he/him]
> Studenohorská 25
> 84103 Bratislava
> Slovakia
>
> ___
> Cmdist mailing list
> Cmdist@ccrma.stanford.edu
> https://cm-mail.stanford.edu/mailman/listinfo/cmdist
>
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