Re: Scan of Emacs regexp mistakes

[Paul Eggert]

On 4/14/20 3:52 AM, Mattias Engdegård wrote:

>  (defvar authors-obsolete-files-regexps
> -  '(".*loaddefs.el$"                 ; not obsolete, but auto-generated
> +  '(".*loaddefs\\.el$"                       ; not obsolete, but auto-generated
>      "\\.\\(bzr\\|cvs\\|git\\)ignore$"                ; obsolete or 
> uninteresting
>      "\\.arch-inventory$"

Should those trailing "$"s be changed to "\\'"s?

>  ;; Match anything but `.' and `..'.
> -(defvar dired-re-no-dot "^\\([^.]\\|\\.\\([^.]\\|\\..\\)\\).*")
> +(defvar dired-re-no-dot (rx (or (not ".") "...")))
...
>  (defconst directory-files-no-dot-files-regexp
> -  "^\\([^.]\\|\\.\\([^.]\\|\\..\\)\\).*"
> +  "[^.]\\|\\.\\.\\."
>    "Regexp matching any file name except \".\" and \"..\".")

We shouldn't have two names for the same variable. I suggest obsoleting 
dired-re-no-dot and replacing its only use with directory-files-no-dot-files-regexp.

As Drew's comments make evident, the doc string is unclear.  It should be 
something like 'Regexp that matches part of a nonempty string if the string is 
neither "." nor "..".'

>      (let ((files (directory-files
> -                 directory t "^\\([^.]\\|\\.\\([^.]\\|\\..\\)\\).*"))
> +                 directory t (rx (or (not ".") "..."))))

Shouldn't this and similar uses of (rx (or (not ".") "...")) be replaced by 
directory-files-no-dot-files-regexp?  That would be clearer.

I agree with you that directory-files should not return "." and "..", though 
that indeed is a different topic.