Re: forbidden comparison

["Ruud H.G. van Tol" <rvtol@isolution.nl>]

On 2022-01-12 09:46, Bill Allombert wrote:
> On Wed, Jan 12, 2022 at 04:14:47AM +0100, Ruud H.G. van Tol wrote:

> > I expected this to just work:
> > my(v=23, c3=7); while( my(c=c3*2); c < v, c3=c ); print([v,c3]);
> > Now changed it to;
> > my(v=23, c3=7);while( c3*2 < v, c3*=2 ); print([v,c3]);
> > [23, 14]
> > With 'if', this works:
> > ? my(v=23, c3=7); if(my(c=c3*2)*0+c, print(c))
> > 14
> > but while has an extra scope?
>
> Because the condition in 'while' is evaluated several times, while for
> 'if' it is evaluated only once, so there is no deferred execution
> involved.

Ah indeed, thanks, so I now made it:

my( v= 23, c3= 7);
\\ ...
my( c= c3 * 2 ); while( c < v, c3= c; c*= 2 ); \\un-oddify


What are alternative ways to do such?

-- Ruud