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From: UI0T@DKAUNI2.BITNET (Thomas Koenig)
Newsgroups: comp.lang.modula2
Subject: Re: Overloading Operators: Extension to Language
Message-ID: <"89-10-05-13:54:59.55*UI0T"@DKAUNI2.BITNET>
Date: 5 Oct 89 13:05:18 GMT
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MARKV@UKANVAX writes:
> I really don't see what the arguement is.  If you wan't to return an
> array or record why not just return the pointer?  Visually it is still
> obvious in the code what you are doing and is fast also.  If you want
> to return a new record or array, then there is NEW or ALLOCATE.
>
> -Mark Gooderum
>  MARKV@UKANVAX

The point is the following: If I have to do, for example, complex
arithmetic with complicated formulas, I don't want to have to keep
track of what I have allocated in the meantime.  (Ever try a Newton
iteration with a formula like f(x)=exp((a*x**2+b*x+c)/(d*x+e)) ?)
The derivative in the case above is quite complicated, without the
added bother of either
  1) defining my own stack for calculations
  2) using auxilliary variables for intermediate results (I tried
     that once; the result was a program I could not read although
     I had written it)
  3) allocating space for intermediate results which has to be
     deallocated later (or else I am going to see some very strange
     results when space runs out on the heap)
  4) keeping track of real and imaginary parts seperately
In complicated formulas using complex arithmetic, I don't want to do
any of the four above, because the mathematics is bothersome enough
without the added complexity of bookkeeping.  If I can't do it in
Modula, I will do it in FORTRAN or C (FORTRAN because it already has
complex arithmetic).  I don't want to use either language more than I
can help it, because I think Modula is much superior to both of them
in almost every respect, but at present, Modula does not leave me
much of a choice in such matters.
With the possibilities of returning at least records via function
values and with of passing multidimensional arrays of varying size to
procedures, like level 1 ISO Pascal, which allows the construct

procedure something(var a:array[1..n,1..m] of real); ,

after which the array a and the integers n and m can be accessed,
Modula would be my language of choice for numerical work.  As it is
today, it isn't.

Thomas  Koenig                   UI0T@DKAUNI2.BITNET
                                 UI0T%DKAUNI2.BITNET@CUNYVM.CUNY.EDU
                         (soon)  UI0T@IBM3090.RZ.UNI-KARLSRUHE.DE