Re: line_perp() (?-|) is broken.

Emre Hasegeli <emre@hasegeli.com> writes:
>> Possibly this objection is pointless, because I'm not at all sure that
>> the existing code is careful about how it uses FPeq/FPzero; perhaps
>> we're applying EPSILON to all manner of numbers that don't have units
>> of the coordinate space.  But this won't help make it better.

> The existing code was probably paying attention to this particular
> one, but it fails to apply EPSILON meaningfully to many other places.
> For example lseg_parallel() and lseg_perp() applies it 2 times to the
> same input.  First point_sl() compares x coordinates with FPeq(), and
> then the returned slopes are compared again with FPeq().

Yeah, comparing a slope to EPSILON sure feels wrong :-(

            regards, tom lane