Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ncar!boulder!pratt
From: pratt@boulder.Colorado.EDU (Jonathan Pratt)
Newsgroups: comp.sys.mac.programmer
Subject: Re: XFCN/XCMD string in LSC C v3.0
Message-ID: <8150@boulder.Colorado.EDU>
Date: 15 Apr 89 03:10:51 GMT
References: <1583@ccnysci.UUCP> <2788@pegasus.ATT.COM>
Sender: news@boulder.Colorado.EDU
Reply-To: pratt@boulder.Colorado.EDU (Jonathan Pratt)
Organization: University of Colorado, Boulder
Lines: 20

In article <2788@pegasus.ATT.COM> ech@pegasus.ATT.COM (Edward C Horvath) writes:
>You're not dense: the easiest way for a pascal programmer to end-run the
>globals problem is to declare a "main" PROCEDURE and nest all the
>subroutines within it.
>
I just wanted to point out that C programmers can emulate this nested
globals behavior by doing manually what the Pascal compiler does auto-
magically: simply define the globals as a struct var in the procedure
designated as "main" and pass a pointer to this struct to each "nested"
procedure.  Pascal does this with hidden arguments.  Yes, it does get
a bit ugly if the nesting grows deep.  I noticed that LSP does a pretty
nice job of this for single nesting;  Address register A4 picks up the
hidden globals pointer, so there isn't much overhead.

Jonathan

/* Jonathan Pratt          Internet: pratt@boulder.colorado.edu     *
 * Campus Box 525              uucp: ..!{ncar|nbires}!boulder!pratt *
 * University of Colorado                                           *
 * Boulder, CO 80309          Phone: (303) 492-4293                 */