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Re: overloading functions (Was: Indirect Addressing Question)
From: |
adler |
Subject: |
Re: overloading functions (Was: Indirect Addressing Question) |
Date: |
Fri, 16 Nov 2001 21:20:37 -0500 (EST) |
On Fri, 16 Nov 2001, John W. Eaton wrote:
> On 16-Nov-2001, Paul Kienzle <address@hidden> wrote:
>
> | Matlab decides what function to call based on the type of the
> | first argument, which can be done reasonably cheaply and
> | handles the majority of the cases.
>
> This kind of design decision is what bugs me about Matlab, I think.
> "It will work most of the time. Users won't be too bothered when it
> fails. After all, we don't expect anyone to actually notice the
> inconsistency because it will come up so infrequently."
Here is another idea (with different benifits and problems).
If a function could install a handler which sits "in front" of
currently defined functions, much like TSR type device drivers
did in DOS.
Example:
function y=sum(x)
# do sparse sum - overload current sum
if is_sparse(x)
y= calulate_sparse_sum(x)
else
give_up_and_go_to_covered_function
end
Here give_up_and_go_to_covered_function would throw
away any calculations and call the lower layer function.
Another implementation:
function y=sum(x)
# do sparse sum - overload current sum
if is_sparse(x)
y= calulate_sparse_sum(x)
else
y= feval(__OVERLOADED_FUNCTION__, x);
end
Where __OVERLOADED_FUNCTION__ is dynamically
defined to call the lower layer function.
Advantage:
Can be done without any OO infrastructure
Disadvantages:
Slower than function lookup
Can be inconsistent if multiple overlay functions
are loaded in a different order.
Comments...
_______________________________________
Andy Adler, address@hidden
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-------------------------------------------------------------
- Indirect Addressing Question, Etienne Grossmann, 2001/11/14
- Re: Indirect Addressing Question, Mirek Kwasniak, 2001/11/14
- Re: Indirect Addressing Question, Paul Kienzle, 2001/11/14
- overloading functions (Was: Indirect Addressing Question), adler, 2001/11/15
- Re: overloading functions (Was: Indirect Addressing Question), Paul Kienzle, 2001/11/16
- Re: overloading functions (Was: Indirect Addressing Question), John W. Eaton, 2001/11/16
- Re: overloading functions (Was: Indirect Addressing Question),
adler <=
- Re: overloading functions, Paul Kienzle, 2001/11/20
- semantics of sum, prod, cumsum etc., adler, 2001/11/22
- Re: Indirect Addressing Question, adler, 2001/11/15