Re: emacs-26 99f92da: Improve documentation of 'directory-files-and-attributes'

[Lars Ingebrigtsen <larsi@gnus.org>]

Eli Zaretskii <eliz@gnu.org> writes:

>> +For instance, to get the size of the fourth element in a directory,
>> +you could say:
>> +
>> +  (file-attribute-size (cdr (nth 3 (directory-files-and-attributes "/"))))
>
> That's redundant, I think; we never provide such "hints" anywhere else
> where we describe lists being returned.

I think the Emacs doc strings could do with more code examples in
general...

>> Because (FILE1 FILE1-ATTRS) is a bit ambiguous, since it could mean
>> 
>> ("file-name" (t 27 0 0 (23311 56666 366991 953000) (23220 586 761023
>> 102000) (23220 586 761023 102000) 4096 "drwxr-xr-x" t 2 66306))
>
> No, it cannot mean that, because the text says
>
>   where each FILEn-ATTRS is the attributes of FILEn as returned by
>   `file-attributes'
>
> It doesn't say it's a list.  If we think that's not clear enough we
> can use this instead:
>
>    ((FILE1 FILE1-ATTRS...) (FILE2 FILE2-ATTRS...) ...)

As long as it's clear to the user that they have to say `cdr' to get to
the attributes instead of `cadr', that's fine (and is pretty much what I
did in my version).

I mean, this is a very simple function, but describing what the user has
to do to get to the values is surprisingly difficult due to the
non-opacity of the data structures here.

And sorry for not doing the doc fix on the emacs-26 branch instead of
master; I should know better.

-- 
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   bloggy blog: http://lars.ingebrigtsen.no