in reply to Re: how watch a variable
in thread how watch a variable

Can you please clarify? I have quickly concocted this:

use strict; use warnings; use feature 'say'; use Variable::Magic qw( wizard cast ); use B::Flags; my $x = '1'; cast $x, wizard( # get => sub { say 'getting...' }, ); say B::svref_2object( \$x )-> flagspv; say 1 if $x > 2.2; say B::svref_2object( \$x )-> flagspv; say 1 if $x > 2; say B::svref_2object( \$x )-> flagspv;

and output is as, I think, expected:

RMG,POK,OVERLOAD,pPOK,IsCOW RMG,NOK,POK,OVERLOAD,pNOK,pPOK,IsCOW RMG,IOK,NOK,POK,OVERLOAD,pIOK,pNOK,pPOK,IsCOW

but with getter definition un-commented:

GMG,POK,OVERLOAD,pPOK,IsCOW getting... GMG,POK,OVERLOAD,pPOK,IsCOW getting... GMG,IOK,POK,OVERLOAD,pIOK,pPOK,IsCOW

I'm not OP, just fooling around. My idea was:

use strict; use warnings; use feature 'say'; use Variable::Magic qw( wizard cast ); use B::Flags; package no_int_please { DESTROY { say 'I\'ve been evaluated as integer, HOW DARE YOU?!' if B::svref_2object( @_ )-> flagspv =~ /IOK/ } } my $x = '1'; cast $x, wizard( get => sub { bless $_[0], 'no_int_please' }, ); say "value is $x, let's check it"; say B::svref_2object( \$x )-> flagspv =~ /IOK/ ? 'i' : 's'; say $x > 2 ? '>' : '<'; say B::svref_2object( \$x )-> flagspv =~ /IOK/ ? 'i' : 's';

which therefore won't work if comparison is to NV, but why?

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Re^3: how watch a variable
by ikegami (Patriarch) on Dec 11, 2023 at 03:07 UTC

    If you want to prevent numification, you can use overload to provide a numifier that dies.