2d unique arrays

[Arthur Gold]

Hey folks:

In an attempt to work with unique multi-dimensional arrays, I figured I'd
start with the 2d case...

Consider the following code:

::*Matrix a     :== *{Row a}
::*Row a        :== *{#a}

::Coord         :== (Int,Int)

GetF::Coord  (Matrix a)->(a,Matrix a) | ArrayElem a
GetF (i,j) s = (x,s``)
where
        (r,s`) = uselect   s i
        (x,r`) = uselect_u r j
        s``    = update s` i r`

It doesn't compile (if it did, I guess there would be no question
here...:-) ) and gives the msg:

Type error : conflicting uniqueness information due to argument 1 of
uselect ({})

Has anyone any insight as to what's going on???

Many thanks,

--Artie


   Arthur Gold                           Austin, Texas
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| agold@bga.com  agold@cs.utexas.edu  ArtieGold@aol.com |
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