Thanks Rodrigo,

That makes sense now, although I think it would be clearer to change the last Zone line to stop in 1989 and add one more Zone line like so:

# Zone  NAME            GMTOFF  RULES   FORMAT  [UNTIL]
                        -6:00   Salv    C%sT    1989
                        -6:00     -     CST

The conceptual block that I had to overcome was that I thought of Rules as things that happen every year, and if there's not a rule for that year, it doesn't apply. In other words I didn't grok that "the last rule sticks"

A FAQ would be great, or at least an update to the man page for zic - the man page is great as a reference to what each particular field means, but not so great as a high level explanation of the format.

take care, 

Bobby 


On Sep 26, 2007, at 11:49 AM, Rodrigo Severo wrote:

This is definitely a FAQ. Is there a page with tz FAQ?

Rules define change in the local time. Local time doesn't ends. :)

The year 1988 is the last year that there is any change. The last change mentioned - switch to local time + 0:00 in the last Sun of september - defines the time indefinitely.


Rodrigo Severo


On 9/26/07, Bobby Rullo <br@osafoundation.org> wrote:
Hello,

I have written a timezone library (including a parser) in JavaScript
and am running into a bit of confusion with this particular Zone and
Rule:

# Rule  NAME    FROM    TO      TYPE    IN      ON      AT      SAVE    LETTER/S
Rule    Salv    1987    1988    -       May     Sun>=1  0:00    1:00    D
Rule    Salv    1987    1988    -       Sep     lastSun 0:00    0       S
# There are too many San Salvadors elsewhere, so use America/El_Salvador
# instead of America/San_Salvador.
# Zone  NAME            GMTOFF  RULES   FORMAT  [UNTIL]
Zone America/El_Salvador -5:56:48 -     LMT     1921            # San Salvador
                        -6:00   Salv    C%sT

My question is, what is the applicable Rule for any date after 1988?
The last "Salv" Rule ends in 1988, and the Zone states that Salv is
the Rule from 1921 on (no UNTIL specified)

I've done a "man zic" hoping to see something like "If there is no
applicable Rule, just use the basic offset and assume that the LETTER
is 'S'", but I could not find anything like that. Is that the correct
behavior?

Thanks

Bobby



--
---------------------------------------------------------------------------------------
Rodrigo Severo

Fábrica de Idéias
SBS Quadra 2 - Bloco S - Ed. Empire Center - Sala 1.301
Brasília - DF - CEP 70070-904
Tel. (61) 3321-1357       Fax (61) 3223-1712
---------------------------------------------------------------------------------------