Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!swrinde!cs.utexas.edu!sun-barr!newstop!sun!amdcad!BitBlocks.COM!bvs
From: bvs@BitBlocks.COM (Bakul Shah)
Newsgroups: comp.object
Subject: Re: C as a replacement for assembler (Re: Documenting OO Systems)
Keywords: volatile
Message-ID: <1991Apr9.194126.13457@BitBlocks.COM>
Date: 9 Apr 91 19:41:26 GMT
References: <jls.670817462@rutabaga> <1576@acf5.NYU <4o5G2erk1@cs.psu.edu>
Organization: Free Ideas Foundation
Lines: 30

In <4o5G2erk1@cs.psu.edu> schwartz@groucho.cs.psu.edu (Scott Schwartz) writes:
|The problem with compiling to C is that certain things are impossible
|to express properly and/or safely.  For example, modula 3 has
|difficulty with garbage collection when the C compiler's optimizer
|decides to rearrange or elide code.

This seems like a perfect opportunity for overloading `volatile' --
declare a piece of code volatile to prevent any rearrangement or
elision.  As in

	volatile {
		i = 1;
		i = 2;
		j = 3;
		k = 4;
		for (i = 0; i < 10; i++)
			j += 10*k;
	}

The idea is that every variable within a volatile block is treated
as if stored in volatile storage (with possible side effects).  Now,
to make this even more useful one would need `nonvolatile' so that
access to selected variables can be optimized even within a volatile
block.  Nonvolatile also appeals to my sense of symmetry.

Has anyone done (or thought of doing) this?  Anyway, just an idea
for you language designer wannabes.

Bakul Shah
bvs@bitblocks.com