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From: Jacob Sparre Andersen <sparre@nbi.dk>
Newsgroups: comp.lang.ada
Subject: Re: math: passing function to function
Date: Mon, 30 Apr 2001 14:10:24 +0200
Organization: Centre for Chaos and Turbulence Studies, Niels Bohr Institute
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Staffan:

> I've tried using access to subprogram types to make something like
> function solver(fun: access to function to solve; ...) return long_float;
> which usually compiles ok, but exits raising
> constraint error as soon as the code gets more involved than the
> rudimentary examples given in the RM.

Strange. Have you found out where the constraint error is raised?
(in the "fun" or in "solver")

> I would very much appreciate it if someone could point me to
> some mathematical Ada source code where things like the above
> are bound to be used.

I think there should be an example in "Generic_Least_Squares" in
the collection you can find at:

   http://hugin.ldraw.org/Ada/matematik/

> The latest line of thought is that it might be possible to
> make a generic construction like
> 
> generic
> function fun(X:float) return float renames function_to_solve;
> function solver(...) return float is
> begin
> ......

Have a look at 12.1(22) and 12.1(24) in the LRM.

Jacob
-- 
"hackers have almost lost interest in Windows NT exploits
 because they're becoming so common"