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From: ajs@hpfcla.UUCP
Newsgroups: net.unix
Subject: Re: Commentary
Message-ID: <43800013@hpfcla.UUCP>
Date: Fri, 13-Jul-84 17:28:00 EDT
Article-I.D.: hpfcla.43800013
Posted: Fri Jul 13 17:28:00 1984
Date-Received: Tue, 24-Jul-84 03:15:27 EDT
References: <2967@rabbit.UUCP>
Organization: Hewlett-Packard - Fort Collins, CO
Lines: 52
Nf-ID: #R:rabbit:-296700:hpfcla:43800013:000:1638
Nf-From: hpfcla!ajs    Jul 20 13:28:00 1984

From rabbit!rob (presumably Rob Pike, co-author of tUPE):

> Sorry; i repent. here is an improved version of one of the hoc routines,
> to set a new style of example.
> 
> Here is the original:
> bltin() 
> {
> 
> 	Datum d;
> 	d = pop();
> 	d.val = (*(double (*)())*pc++)(d.val);
> 	push(d);
> }
>
> [ followed by a horrendous example ]

Ugh.  Surely  you jest.  But it does you  discredit,  for you  mockingly
assume there is no better way to do it without getting ugly.

Since  you  fired the  opening  round,  I'll  volley  back with a better
example (in all seriousness).  Forgive me if the comments are erroneous;
I'm not sure from your listing what exactly  this  procedure  DOES.  :-)
And I'm not going to even try to untangle  that  (undoubtedly  efficient
but who cares?) ugly procedure call.


/***********************************************************************
 * B U I L T   I N
 *
 * Call a built-in function with data from the expression stack and
 * advance the procedure pointer as a side-effect.  The ugly procedure
 * call treats the current procedure pointer as a {hell I can't tell,
 * and cdecl doesn't help either, so it bloody well should be explained
 * here or below, because most of us aren't C compilers}.
 */

local void BuiltIn() 
{
	Datum data;			/* working copy */

	data	   = PopData();
	data.value = (* (double (*)()) *proc++) (data.value);
	PushData (data);

} /* BuiltIn */


/***********************************************************************

Alan Silverstein, Hewlett-Packard Fort Collins Systems Division, Colorado
{ihnp4 | hplabs}!hpfcla!ajs, 303-226-3800 x3053, N 40 31'31" W 105 00'43"