Re: Questions about date:parse-date(), date:format-date() and date:date-format

* 险峰 张 <[email protected]> [2006-08-09 09:35]:
> When I read the specifications for date:format-date() and
> date:parse-date(), I am a little confused. They look somewhat
> redundant to me. If I implement the date:format-date(), it
> seems to cover what date:parse-date() can do.

I have no idea how you got that impression. The functions are
complements.

`format-date` takes a date and a format specification and
returns a string describing the date formatted according to the
specification.

`parse-date` takes an arbitrary string and a format specification
and returns the date that the string describes according to the
format specification.

One function does the opposite of the other.

> For example: date:format-date("2005-06-03", "yyyy") is the same
> as date:parse-date("2005-06-03", "yyyy"). Am I right? 

The result is the same, but that’s only because the format you
picked, `yyyy`, produces strings that can be interpreted as a
legal XSD type. If you picked a format that’s not, the functions
would do the opposite of one another.

Regards,
-- 
Aristotle Pagaltzis // <http://plasmasturm.org/>