Increment / Decrement Operator Behavior

[simendsjo]

On Mon, 04 Jun 2012 20:36:14 +0200, Xinok <xinok at live.com> wrote:

> The increment and decrement operators are highly dependent on operator  
> precedence and associativity. If the actions are performed in a  
> different order than the developer presumed, it could cause unexpected  
> behavior.
>
> I had a simple idea to change the behavior of this operator. It works  
> for the postfix operators but not prefix. Take the following code:
>
> size_t i = 5;
> writeln(i--, i--, i--);
>
> As of now, this writes "543". With my idea, instead it would write,  
> "555". Under the hood, the compiler would rewrite the code as:
>
> size_t i = 5;
> writeln(i, i, i);
> --i;
> --i;
> --i;
>
> It decrements the variable after the current statement. While not the  
> norm, this behavior is at least predictable. For non-static variables,  
> such as array elements, the compiler could store a temporary reference  
> to the variable so it can decrement it afterwards.
>
> I'm not actually proposing we actually make this change. I simply  
> thought it was a nifty idea worth sharing.

If I ever saw a construct like that, I would certainly test how that  
works, then rewrite it.
I wouldn't find it natural with the new behavior either. I would expect  
"543" or "345".
How often do you come across code like that? I think it's an anti-pattern,  
and shouldn't be encouraged even if it was easier to understand.