On Tuesday, May 3, 2016 at 8:06:23 PM UTC-7, Chris Riddoch wrote:
>
> Hi, folks.
>
> I've been working with postgresql's tstzrange types with sequel, and have
> found the convert_infinite_timestamps option very helpful in making it
> possible to handle the ranges where 'infinity' or '-infinity' is a value at
> one of the ends of a tstzrange. The PGRange seems meant to work with
> ranges where the native ruby Range class just doesn't have the features
> necessary.
>
Correct. PostgreSQL supports more range types than ruby, so you can't use
ruby's range types to represent all PostgreSQL range types, hence the
reason for PGRange.
>
> But the current implementation of cover? for the PGRange class, line 407
> to 411 [0] delegates to the native ruby Range class. When I call cover? (or
> any of the other methods delegated to Range) on a PGRange that uses one of
> the infinity values, I get an error like the following:
>
> ArgumentError: bad value for range
> from .../gems/sequel-4.34.0/lib/sequel/extensions/pg_range.rb:500:in
> `initialize'
>
> I started writing tests for implementations of these methods for the
> PGRange class to at least not delegate in the cases where
> convert_infinite_timestamps is set to :float (which is what I'm using) or
> would otherwise result in an ArgumentError...
>
> Working through this, I now think the logic of valid_ruby_range? is
> incomplete. But not all cases of infinity will problems, so I can't just
> test for that:
>
> ((1.0)..Float::INFINITY).cover?(10) => true
>
> Here's a curiosity I just found by way of a stack overflow post[1]:
> DateTime::Infinity.new
>
> (DateTime.now()..DateTime::Infinity.new).cover?(DateTime.new(2017,1,1,0,0,0))
> => true
>
> It took a little trying to get a range that goes the other direction, but
> this seems to work:
>
> (Date.new(2000,1,1,Date::GREGORIAN)..DateTime.now()).cover?(DateTime.new(2012,1,1,0,0,0))
>
> => true
>
> So maybe one option is to make use of these when converting DateTime
> ranges, instead of of the current convert_implement_timestamps code? It
> sort of seems like every option is a bit of a hack. I've already started
> on some tests, which I've put into my fork on github, in a branch
> pg-tstzrange-cover. [2] Suggestions?
>
I suppose I would be OK with having PGRange#cover? not delegate to
to_range. Maybe something like the following:
class Sequel::Postgres::PGRange
def cover?(value)
return false if empty?
b = self.begin
return false if b && b.send(exclude_begin? ? :>= : :>, value)
e = self.end
return false if e && e.send(exclude_end? ? :<= : :<, value)
true
end
end
Can you try that out and see if it works for you? If so, add some specs
and submit a pull request for it?
Thanks,
Jeremy
>
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