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From: erin@otago.ac.nz (John Gee)
Newsgroups: comp.lang.pascal
Subject: Re: procedures as parameters to procedures
Message-ID: <1991Feb4.114449.74@otago.ac.nz>
Date: 3 Feb 91 23:08:55 GMT
References: <25782@adm.brl.mil>
Organization: University of Otago, Dunedin, New Zealand
Lines: 56

In article <25782@adm.brl.mil>, VMAN%PACEVM.BITNET@uga.cc.uga.edu ( cliff) writes:
> hi,
>  we run vs pascal 2.1 on vm/sp 6.  is it possible to pass as a procedure
>  parameter a procedure name with a parameter list?  for example,
> 

IMHO No. Need to pass the parameters separately. Reasoning
for why it won't work follows.

> program main (input,output);
> 
> var word: packed array(1..5) of char;
> 
> procedure abc(procedure xyx(var string: packed array(1..5) of char);i:integer);
>           .

Telling pascal that you will give it a procedure. So that it can
type check, you specify the parameter types that the procedure
takes. (In this case a string)

>           .
> procedure blah(var string: packed array(1..5) of char);
>           .
>           .
>   begin (* main program *)
>           .
>           .
>    abc(blah(word),3)
>   end.
> 

IMHO this tries to pass the result returned by a procedure, as a
procedure parameter - ie it doesn't make sense. Think of putting
a function there instead of a procedure, since you have the
parameters, it seems likely it will evaluate if before passing
it? You need to do something like

   procedure abc (
      procedure xyx (var string: packed array(1..5) of char);
      var word: packed array (1..5) of char);
      i: integer);
   ...
   abc (blah, word, 3);

instead.

-
The views expressed here are my own, and not necessarily those of my employer.

John Gee
Systems Programmer		E-mail:	ERIN@otago.ac.nz (internet)
Computing Services Centre	Phone:	+64 3 4798596
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