Geometric types in SELECT?

First off, thanks for the answer to my earlier question -- I've
become less misguided since (I hope!)

One of my tables uses the point data type. I wanted to use this to
find points close to one another. Unfortunately, when I do something
like:

=>select * from address order by length ( '((0,0), coord)'::lseg );

or

=>select length( '((0,0),coord)'::lseg ) from address;

I receive this error:

Bad lseg external representation '((0,0), coord)'

If I replace coord with an actual value, I don't get the error. Am I
somehow mangling the syntax? I've tried a number of different formats
for the query, with the same error each time. Is it possible to do this?

Thanks,

-mike

--

And though the holes were rather small
They had to count them all
Now they know how many holes it takes to fill the Albert Hall
*I'd love to turn you on*

-- Beatles, "A Day in the Life"

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