On Sat, Dec 7, 2019 at 9:36 PM ToddAndMargo via perl6-users
<perl6-us...@perl.org> wrote:
>
> On 2019-12-07 18:30, Mark Senn wrote:
> >> Corrected section
> >>
> >> my %h = a => "x", b=>"r", c=>"z";
> >> if %h<d> { say "exists"; } else { say "DOES NOT exist"; }
> >> DOES NOT exist
> >>
> >> if %h<b> { say "exists"; } else { say "DOES NOT exist"; }
> >> exists
> >
> > Hi.
> >
> > The following code prints DOES NOT exist twice.
> >
> > my %h = a => "x", b=>0, c=>"z";
> > if %h<d> { say "exists"; } else { say "DOES NOT exist"; }
> >
> > if %h<b> { say "exists"; } else { say "DOES NOT exist"; }
> >
> >
> > I changed the b=>"r" to b=>0. I think it is evaluating
> > the b element as a boolean---I think the exists adverb
> > needs to be used to check for existence.
> >
> > -m
> >
>
> Hi Mark,
>
> Oh bugger!
>
>
> This is what I get:
>
> $ perl6
> To exit type 'exit' or '^D'
> > my %h = a => "x", b=>"r", c=>"z";
> {a => x, b => r, c => z}
>
> > if %h<d> { say "exists"; } else { say "DOES NOT exist"; }
> DOES NOT exist
>
> > if %h<b> { say "exists"; } else { say "DOES NOT exist"; }
> exists
>
>
> Would someone else please run my code and see if
> they can reproduce Mark's error?
>
> Many thanks,
> -T
Mark is correct. Changing values to 1 or 0 results in if/else
evaluating as a True/False:
mbook:~ homedir$ perl6
To exit type 'exit' or '^D'
> my %i = a => 1, b=> 0, c=> 1;
{a => 1, b => 0, c => 1}
> if %i<a> { say "exists"; } else { say "DOES NOT exist"; }
exists
> if %i<b> { say "exists"; } else { say "DOES NOT exist"; }
DOES NOT exist
> if %i<d> { say "exists"; } else { say "DOES NOT exist"; }
DOES NOT exist
>
> $*VM
moar (2019.07.1)
>
HTH, Bill.
