Path: utzoo!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!sco!seanf
From: seanf@sco.COM (Sean Fagan)
Newsgroups: comp.lang.misc
Subject: Re: NOT Educating FORTRAN programmers to use C
Message-ID: <4561@scolex.sco.COM>
Date: 24 Jan 90 13:58:59 GMT
References: <17036@megaron.cs.arizona.edu> <14203@lambda.UUCP>
Reply-To: seanf@sco.COM (Sean Fagan)
Organization: The Santa Cruz Operation, Inc.
Lines: 28

In article <14203@lambda.UUCP> jlg@lambda.UUCP (Jim Giles) writes:
>This is not true.  There is _NO_ case that I'm aware of that parenthesis
>are _REQUIRED_ in Fortran (ADA, Pascal, etc.) when they are not also
>_REQUIRED_ in C - and with the _SAME_ consequences with respect to
>optimization.  It is with _OPTIONAL_ parenthesis that the languages
>differ.  In C, the compiler ignores them, in all the other languages
>the compiler must evaluate in parenthesis order.  So, the trade-off you
>mention is under direct user control in all languages but C.

1.  Given
	a + b + c - e - f;

I'm happy to let the compiler rearrange things as much as possible to
generate fast code.  In FORTRAN, by your own admission, you can't do that.

2.  Given

	((((a + b) + c ) -e ) - f);

The compiler is free to rewrite this, *IFF* the result would be the same!
If you're using shorts, and overflows are ignored, then, probably, it can do
what it wants to.  If, however, the result is *not* the same, then the
compiler cannot do this, and, if it does, it's a bug.

-- 
Sean Eric Fagan  | "Time has little to do with infinity and jelly donuts."
seanf@sco.COM    |    -- Thomas Magnum (Tom Selleck), _Magnum, P.I._
(408) 458-1422   | Any opinions expressed are my own, not my employers'.