If you allow dot, you'll want to add checks that "." and ".." are not used as file name components.

Our guidelines in Theory prevent us from doing this to ourselves. It states, "Within a file name component, use only ASCII letters, [dot, hyphen, and underscore]." (Slash delimits components, and plus is used in some Etc zones.) However, Theory also says to "[o]mit [dot] from abbreviations in names".

So the question is: Could we imagine some use case where someone (likely not us) might want to use a dot that makes this worthwhile?

A related question that arose along those lines: Are we already checking that components do not start with a hyphen? Theory specifies that as well.

--
Tim Parenti

On 25 June 2014 20:52, Arthur David Olson <arthurdavidolson@gmail.com> wrote:

I limited the BENIGN list to charcters other than [a-zA-Z0-9] currently used in distribution file names; <dot> could be added.

(The "etcetera" file has lines such as "Zone Etc/GMT+10...")

On an unrelated note: I checked; "zic -v" already checks abbreviations and issues warnings.

--ado
On Wed, Jun 25, 2014 at 8:36 PM, Jonathan Leffler <jonathan.leffler@gmail.com> wrote:
Dot is pretty benign in a file name, isn't it?

POSIX defines the portable file name character set as:

3.278 Portable Filename Character Set
The set of characters from which portable filenames are constructed.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
a b c d e f g h i j k l m n o p q r s t u v w x y z
0 1 2 3 4 5 6 7 8 9 . _ -
(http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap03.html#tag_03_278)
or
(http://pubs.opengroup.org/onlinepubs/9699919799/toc.htm and under Base Definitions, section 3 Definitions, and thence to 3.278).
Your list omits . <dot> and adds + <plus> (and includes / <slash> the path separator).
On Wed, Jun 25, 2014 at 4:37 PM, Arthur David Olson <arthurdavidolson@gmail.com> wrote:

To help ensure that non-ASCII characters don't appear in distribution filenames,
changes to zic.c so that the "-v" option warns about them. Both attached and
tab-mangled below.

    --ado

*** /tmp/,azic.c    2014-06-25 19:32:44.803874900 -0400
--- /tmp/,bzic.c    2014-06-25 19:32:44.906880800 -0400
***************
*** 134,139 ****
--- 134,140 ----
static int    itsdir(const char * name);
static int    lowerit(int c);
static int    mkdirs(char * filename);
+ static void    namecheck(const char * name);
static void    newabbr(const char * abbr);
static zic_t    oadd(zic_t t1, zic_t t2);
static void    outzone(const struct zone * zp, int ntzones);
***************
*** 621,632 ****
--- 622,652 ----
    return (errors == 0) ? EXIT_SUCCESS : EXIT_FAILURE;
}

+ #define BENIGN    "+-_/"
+
+ static void
+ namecheck(const char * const name)
+ {
+     register const char *    cp;
+
+     if (!noise)
+         return;
+     for (cp = name; *cp != '\0'; ++cp)
+         if (!isascii(*cp) ||
+             (!isalnum(*cp) && strchr(BENIGN, *cp) == NULL)) {
+ warning(_("file name %s has non-ASCII-alphanumeric character other than %s"),
+                     name, BENIGN);
+             return;
+         }
+ }
+
static void
dolink(const char *const fromfield, const char *const tofield)
{
    register char *    fromname;
    register char *    toname;

+     namecheck(tofield);
    if (fromfield[0] == '/')
        fromname = ecpyalloc(fromfield);
    else {
***************
*** 1495,1500 ****
--- 1515,1521 ----
    void *typesptr = ats + timecnt;
    unsigned char *types = typesptr;

+     namecheck(name);
    /*
    ** Sort.
    */

--
Jonathan Leffler <jonathan.leffler@gmail.com> #include <disclaimer.h>
Guardian of DBD::Informix - v2013.0521 - http://dbi.perl.org
"Blessed are we who can laugh at ourselves, for we shall never cease to be amused."