Re: grammar question ?

[Ilya Zakharevich <ilya@math.ohio-state.edu>]

On Wed, Nov 08, 2000 at 08:05:34PM +0100, Karim BELABAS wrote:
> It's not a generic assignment: it's actually deferred until the loop body
> is evaluated. And it works so that the loop index is automatically local to
> the loop, i.e is restored to its former value when the loop ends. After
> 
>   x = 0; for (x=1, 10, print(x))
> 
> the value of x is 0.

Vaguely related note: I think it is quite easy to allow definition of
such *user-defined* constructs.  The syntax may be like this:

  for_squares(x==init,last,func()) = { 
    local(var_numbered(x));
    local(n);
    n = ceil(sqrt(x));
    while( n^2<=last, set_var_numbered(x,n^2); n=n+1; eval(func) )
  }

so that on entry x is set to be the variable number (or maybe it is
better to alias it?), and func set to the string value of the
corresponding argument...

Ilya