[mercury-users] MCORBA

[Luke Evans]

>From memory, we are only using unions for discriminated types (although
those types can, of course, be abstract).  For instance we have a cell_value
type (for multidimensional OLAP data) which can be a string, a single or
double precision floating point number, a date (structure) or a special
value (like a NaN) that can represent other states than the cell having a
value.

I'll have a quick look to see if anything surprising has been added since I
knew the IDL intimately, but this is unlikely.

Luke


-----Original Message-----
From: David Glen JEFFERY [mailto:dgj at cs.mu.OZ.AU]
Sent: 17 June 1999 08:02
To: mercury-users at cs.mu.OZ.AU
Subject: Re: [mercury-users] MCORBA


On 17-Jun-1999, Fergus Henderson <fjh at cs.mu.OZ.AU> wrote:
> 
> How often is this IDL feature used?

My intuition says that most of the time unions would be switching on
an enumeration. I'm really just speculating, though, having not seen much
IDL that actually uses unions.

> The obvious thing to do is to support unions in the natural way in
> the easy cases, and for hard cases, either don't support them at all,
> or map them to Mercury discriminated unions where the alternatives
> are just labelled `case1', `case2', ...

Not a bad idea.


dgj
-- 
David Jeffery (dgj at cs.mu.oz.au) | If your thesis is utterly vacuous
PhD student,                    | Use first-order predicate calculus.
Dept. of Comp. Sci. & Soft. Eng.|     With sufficient formality
The University of Melbourne     |     The sheerist banality
Australia                       | Will be hailed by the critics:
"Miraculous!"
                                |     -- Anon.
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