On 28 Feb 2017, at 01:04, David Pirotte <da...@altosw.be> wrote: > Hi Andy, > >> So! Release blockers. >> ... > > Not a blocker, at all, but I was thinking to this, wrt manipulating (very) > large > vectors, arrays, lists ... > > -] repl - truncated-print > > Right now I edit the installed (system repl common), and wrote a tip in > Guile-CV's > manual so users can do that as well: less then optimal :). It would be nice > to > provide an option, so users could set it 'just like that', in the repl, or as > a > global config in their .guile (I did see lloda does that in his for arrays, > but it's > not an obvious option to set, it is a 'sophisticated' little piece of code > (for an > end-user at least)).
I think this is the minimum for .guile: (import (system repl common) (ice-9 format)) (repl-default-option-set! 'print (lambda (repl val) (format #t "~200@y" val))) That doesn't seem so bad. For the current repl you can do: (repl-option-set! (car (fluid-ref *repl-stack*)) 'print (lambda (repl val) (format #t "~200@y" val))) We could have shortcuts, something like: ; not in current Guile (repl-default-print-truncate! 200) (repl-print-truncate! (current-repl) 200) What do you think? I'm guilty of finding these things by googling mailing lists and browsing the Guile source... repl-default-option-set! is documented, but repl-option-set!/ref isn't. There seems to be a chunk of text missing here: https://www.gnu.org/software/guile/manual/html_node/System-Commands.html There's one thing that I realized recently, that something like #1:5(a b c d e) or #@0:5(a b c d e) is actually valid read syntax, although #:5(a b c d e) is invalid, not sure if it should be. (Of course the truncated-print output doesn't *have* to be readable.) So it may be a good idea to print truncated arrays/vectors/etc that way, maybe even by default. > -] error(s) while manipulating (very) large vectors or arrays > > Unlike the above, it appears there is currently no way to have error (the > procedure) > and raised exceptions in general, to use truncated-print, it would be cool to > 'link' > the above option so error reports use it as well. Agreed, this is a serious issue for me. Unfortunately the current API lets the error reporter decide how to print the arguments using a format string (cf scm_error) so you have to work around that. The hack I posted recently to guile-devel was buggy, so I'll repeat it here without the bug. It needs this patch: http://git.savannah.gnu.org/gitweb/?p=guile.git;a=commitdiff;h=6118d9dd0cc7733ca71c6b803a942a15f463663a and this code in .guile: ; Truncate output on exceptions. Requires exception-format to be used in ice-9/boot.scm. ; FIXME doesn't handle e.g. "x~~~s" -> "x~~~@y" (define (rewrite-fmt fmt) (let loop ((f "") (b 0)) (let ((next (string-contains-ci fmt "~s" b))) (if next (loop (if (or (zero? next) (not (char=? #\~ (string-ref fmt (- next 1))))) (string-append f (substring fmt b next) "~200@y") f) (+ next 2)) (string-append f (substring fmt b)))))) (define (truncate-format port fmt . args) (apply format port (rewrite-fmt fmt) args)) (set! exception-format truncate-format) This can't work in general, since the call to scm_error may decide to use ~a instead of ~s, etc. I'd limit further what can go into that format string. But I would welcome a proper solution. Regards —lloda
