I propose format_datetime should use the time_zone parameter

[autarch]

Migrated from rt.cpan.org #113568 (status was 'open')

Requestors:

• ALTREUS@cpan.org

From altreus@cpan.org on 2016-04-04 16:42:58:

I don't really think it makes sense for format_datetime to pass through to strftime on the DT object, because this completely ignores the fact the formatter has a time zone on it.

To my mind, the whole point of the formatter having a time zone is that it will convert $timezone <-> UTC.

Now, the output of parse_datetime is actually a DateTime object that knows it is $timezone, but that seems to me to be functionally equivalent to a UTC object - it's normalised data with sufficient metadata to be converted to any unit.

It seems sensible that if the formatter has a time zone specified, the user would want any strings formatted with it to be output based on that time zone. I would argue that is the whole point in the formatter: a container for the metadata required to convert the normalised DateTime object into a representation for output.

Currently, it seems to violate POLA.

[autarch]

From drolsky@cpan.org (@autarch) on 2016-08-21 22:39:58:

On Mon Apr 04 12:42:58 2016, ALTREUS wrote:

I don't really think it makes sense for format_datetime to pass
through to strftime on the DT object, because this completely ignores
the fact the formatter has a time zone on it.

To my mind, the whole point of the formatter having a time zone is
that it will convert $timezone <-> UTC.

Now, the output of parse_datetime is actually a DateTime object that
knows it is $timezone, but that seems to me to be functionally
equivalent to a UTC object - it's normalised data with sufficient
metadata to be converted to any unit.

It seems sensible that if the formatter has a time zone specified, the
user would want any strings formatted with it to be output based on
that time zone. I would argue that is the whole point in the
formatter: a container for the metadata required to convert the
normalised DateTime object into a representation for output.

Currently, it seems to violate POLA.

Using this module to format DateTime is almost entirely pointless. DateTime itself implements a strftime method. Just use that instead, or better yet use the CLDR formatting, which gives you a lot more options.