Date.to_time error

[Kev Jackson]

Hi,

I'm messing with some dates and (being new to ruby), I've come across an
interesting problem

I have a new date object

start_date = Date.new 1901, 01, 01

now I can call

start_date.respond_to?to_time)

and everything is fine, and I get true back

assert_equal true, start_date.respond_to?to_time)

however

time = start_date.to_time

breaks with an Argument out of range error

This is on the version of Ruby on my WinXP machine here at work, (one
click installer - cheers for that, so much easier than the hell that is
installing on MacOSX)

Any ideas what I should be doing? Looking at the API docs, a Date
object shouldn't respond to to_time - indeed I can't find the to_time
method - but maybe I'm looking in the wrong place

Sorry if this is a ridiculous message, but I'm kinda interested in how I
should approach this - it's someone elses code and I don't want to use a
Time object instead of the original date, I think it's a bug in the code
(that I found - w00t!), but I want to be sure before I post bug reports
etc etc

Kev

 

[Kev Jackson]

Hi,

I'm messing with some dates and (being new to ruby), I've come across
an interesting problem

I have a new date object

start_date = Date.new 1901, 01, 01

Interestingly it seems to be a real bug in the code (yes respond to
myself but whatever).

I've now discovered that any date prior to 1970 breaks when to_time is
called on it.

Nice, so I have to update the code (just unit tests) to use at a minimum
1970 for this test case

Kev

 

[Dimitri Aivaliotis]

Hi Kev,

I've now discovered that any date prior to 1970 breaks when to_time is
called on it.
=20

That would make sense, since Time represents time since the Epoch.=20
See http://www.rubycentral.com/ref/ref_c_time.html for further
details.

- Dimitri

 

[Charles Steinman]

This is on the version of Ruby on my WinXP machine here at work, (one
click installer - cheers for that, so much easier than the hell that is
installing on MacOSX)

What do you mean? Ruby is included in the Mac OS X standard install.
Can't get any easier.

 

[Kev Jackson]

Kev Jackson wrote:



What do you mean? Ruby is included in the Mac OS X standard install.
Can't get any easier.

ruby 1.6 is installed as standard, installing ruby 1.8 over a modem so
that I can download rails and play with that is not as easy as I'd
like. There is an installer now, but it's for Tiger and I'm stuck on
Panther

Kev

 

[James Edward Gray II]

ruby 1.6 is installed as standard, installing ruby 1.8 over a modem
so that I can download rails and play with that is not as easy as
I'd like. There is an installer now, but it's for Tiger and I'm
stuck on Panther

Tiger also ships with Ruby 1.8.2 installed, just FYI.

James Edward Gray II

 

[Brian Candler]

That would make sense, since Time represents time since the Epoch.
See http://www.rubycentral.com/ref/ref_c_time.html for further
details.

But what's wrong with negative time values?

Unix supports this AFAIK. This with FreeBSD:

$ date -r -1000000
Sat Dec 20 11:13:20 BST 1969

And the big time wraparound occurs at t = 2^31, not t = 2^32:

$ date -r 2147483647
Tue Jan 19 03:14:07 GMT 2038

Regards,

Brian.

 

[Dimitri Aivaliotis]

But what's wrong with negative time values?
=20
Unix supports this AFAIK. This with FreeBSD:
=20
$ date -r -1000000
Sat Dec 20 11:13:20 BST 1969
=20
And the big time wraparound occurs at t =3D 2^31, not t =3D 2^32:
=20
$ date -r 2147483647
Tue Jan 19 03:14:07 GMT 2038
=20

Hmm...never thought of that.

Time.at(-2147483648)
=3D> Fri Dec 13 21:45:52 CET 1901

It does work...

On my machine (Linux, Ruby 1.8.2), the to_time method isn't in the
standard library: it's a part of facets (I've got version 0.7.2), and
it's defined as follows:

class Date
def to_time(form =3D :local)
::Time.send(form, year, month, day)
end
end

It also seems to work for me:

start_date =3D Date.new(1901, 01, 01)
start_date.to_time
=3D> Fri Dec 13 21:45:52 CET 1901

Maybe the OP could post a few more details about his set-up. Which
version of the one-click installer is it? Or maybe it's a platform
problem (WinXP not supporting negative times)?

- Dimitri

 

[Kev Jackson]

... on win32. Complain to your vendor for having an unsigned time format.

yeah because complaining to Microsoft about their crappy software has
always been a winning strategy! I have to use Windows at work, it
suprised me that the 1970 date would be significant to Windows in
anyway. Presumambly this is something to do with the half-arsed
not-quite posix that Windows attempts to be.

Kev