Feature request: extending comma operator's functionality

[Jonathan M Davis]

On Thursday, October 04, 2012 23:11:58 Tommi wrote:
> Could you change it so that expressions, that are separated by
> commas and inside an if-clause, would have visibility to the
> variable defined in the first expression? Easier to show than to
> explain:
> 
> int getInt()
> {
> return 11;
> }
> 
> void main()
> {
> if (int n = getInt(), n > 10) // undefined identifier n
> {
> //...
> }
> 
> if (int n = getInt(), ++n, n > 10) // undefined identifier n
> {
> //...
> }
> 
> if (int n = getInt(), getInt() > 10) // OK
> {
> //...
> }
> }
> 
> That would make it possible to define variables in the smallest
> possible scope, and not pollute the namespace of the enclosing
> scope.

If you want to restrict the scope of a variable, you can simply use another 
set of braces to create a new scope. It might be more verbose than desirable, 
but it works just fine. e.g.

{
 int n = getInt();
 if(n > 10)
 {
 ...
 }
}

As it stands, there's a good chance that the comma operator is actually going 
to be _removed_ from the language (aside from specific use cases such as inside 
for loops). So, I don't think that there's much chance of it being expanded at 
all.

- Jonathan M Davis