Re: [PATCH] Revive line type

Peter Eisentraut <peter_e@gmx.net> writes:
> Complete the implementations of line_in, line_out, line_recv,
> line_send.  Remove comments and error messages about the line type not
> being implemented.  Add regression tests for existing line operators
> and functions.
> ---
> This just revives existing functionality, doesn't add anything new.
> One thing that the original code did not settle was how to convert a
> line in form Ax+By+C=0 to the two-points output form.  Obviously, you
> can just pick to random points on the line, but I wonder whether there
> is a more standard solution.

ISTM printing a line as two points is an unfortunate representational
choice altogether.  If the internal form is Ax+By+C=0, shouldn't the
text form expose A,B,C directly?  What you've got here necessarily
suffers a lot of roundoff error during I/O conversions, and so it seems
pretty likely to fail dump-and-reload tests.
        regards, tom lane