[Nickle]Sequencing of expressions with side effects

[Keith Packard]

Around 10 o'clock on Jul 23, Bart Massey wrote:

> Naah.  If you're gonna honor the precedence of operators in
> expression evaluation, you should also honor the
> associativity: assignment operators associate right-to-left,
> and should thus evaluate right-to-left.

I disagree.  A strict left to right rule fixes problems with lexical scope 
of identifiers:

	a = (int b = 2) ** b;

Associativity only affects implicit parenthesization, I don't think it 
should affect the evaluation order.

>   a += b --> a = (int x1 = a) + (int x2 = b);
> which would still be consistent with the principles
> espoused above.

This isn't quite right -- 'a' must be evaluated only once in the 'a += b' 
case:

	a += b		-> 	(poly* ap = &a), (*ap = *ap + b)

-keith