Hello, On 2024-07-29 00:34:14 +0000, Marius via Bug reports for GUILE, GNU's Ubiquitous Extension Language wrote: > Good evening, > > I don't know if this is actually a Guile bug or a documentation bug, but I'm > currently learning Guile from the "Guile reference manual" and I've found a > mismatch between what the documentation says and what "my" guile does. I use > Guile 3.0.9. > > In my Guile instance (from what I can deduce), last-index is a procedure that > returns the index of the first element of a list that matches with a > s-expresion. > > For example: > > (list-index '(1 2 3) 3) -> 2 > (list-index '(height width) 'width) -> 1 > > But the documentation says otherwise > (<https://www.gnu.org/software/guile//manual/guile.html#SRFI_002d1-Filtering-and-Partitioning>): > > list-index pred lst1 lst2 ... > > Returns the index of the first set of elements, one from each of lst1 lst2 > ..., which satisfies pred.
This is documentation for SRFI-1, and that is not available by default (at least
not fully), you need to (use-modules) it. See below.
>
>
> If I try to run list-index examples (from the documentation) I get an error
> because it doesn't know how to deal with a procedure as the first argument.
>
>
> I'm missing something? I understand that list-index it's defined in SRFI-1
> and maybe a Guile definition is shadowing the SRFI-1 definition. But where is
> the Guile documentation for this shadowing list-index? In the Guile Reference
> Manual list-index it's only described inside SRFI-1 module.
It seems that Guile provides 2 different list-index procedures. One defined in
the ice-9/boot-9.scm, and one in the srfi-1 module. By default the boot-9's one
is available.
$ guile -q
GNU Guile 3.0.9
Copyright (C) 1995-2023 Free Software Foundation, Inc.
Guile comes with ABSOLUTELY NO WARRANTY; for details type `,show w'.
This program is free software, and you are welcome to redistribute it
under certain conditions; type `,show c' for details.
Enter `,help' for help.
scheme@(guile-user)> list-index
$1 = #<procedure list-index (l k)>
scheme@(guile-user)> ,use (srfi srfi-1)
scheme@(guile-user)> list-index
$2 = #<procedure list-index (pred clist1 . rest)>
Notice that by importing srfi-1 the list-index changes to the documented one.
You are right that the "default" list-index indeed does not seem to be
documented. It also uses `eq?' for comparisons and does not allow changing
that.
I hope this sheds some light on the problem.
Tomas
--
There are only two hard things in Computer Science:
cache invalidation, naming things and off-by-one errors.
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