Path: utzoo!attcan!uunet!lll-winken!ames!oliveb!felix!arcturus!mitch
From: mitch@arcturus.UUCP (Mitchell S. Gorman)
Newsgroups: comp.lang.pascal
Subject: Re: (re:)**3 function return value
Summary: This may or may not be any help...
Message-ID: <3968@arcturus>
Date: 17 Mar 89 23:50:34 GMT
References: <18654@adm.BRL.MIL>
Organization: Rockwell International, Anaheim, CA
Lines: 52

In article <18654@adm.BRL.MIL>, MATHRICH@umcvmb.missouri.edu (Rich Winkel UMC Math Department) writes:
> Arghhh!  I apologize for using so much bandwidth for this problem.  It's my
> fault for not giving a good example of what I want to do.  Let me try again:
> 
> function what(var where:string):string;
> begin
>    what:=where;
>    delete(what,5,10);
> end;
> 
> Ok, so I need to:
> 1. Use a VAR parameter to the function to avoid stacking a large variable,
> 2. Avoid modifying the var parameter to the function,
> 3. Avoid defining temp variables (which use up stack space)
> 4. Do an operation which involves modifying a copy of the var parameter.


Well, I'm going to reply specifically to the example that you list here, i.e., 
returning a truncated copy of the string.  If you think that this'll work for
whatever REAL manipulations you want to do, great.  If not, well, I don't mind
typing a lot of stuff, and potentially opening myself up to ridicule from every-
one in netland!!! :^)

Using this method will obviously depend on your ability to allocate dynamic mem-
ory, but what about setting up a pointer to string[5], and assigning that dyn-
amic variable to the original?  In code form:

var
	what : string[10];
	temp : ^string[5];

begin
	...
	temp^:=what;
	...

This won't take up much additional room in conventional memory, just a long word
for the pointer address.  When you assign a long string to a string variable of
a lesser length, it automatically truncates.  So here you avoid using a function
call completely.

I once had to write a best-guess type string pattern matching program, and 
trying to keep a couple thousand string[50] variables in an array can eat up 
memory REAL fast (ok, ok, I was young and foolish then!  :^).  What I wound up
doing was keeping an array of pointers to strings; whence comes this idea you
might want to consider.

Have fun.

	Mitch @ Rockwell, Anaheim

Disclaimer:	I almost never run out of memory any mo