In general having "use warnings" on is a good idea, but at least in one case it makes code unnecessary complex. Specifically, when I would like to print out debugging messages. For examples this code: 
use 5.010;
use strict;
use warnings;

my $x = 23;
my $y;

debug("x='$x' y='$y'");
debug(sprintf "x='%s' y='%s'", ($x // ''), ($y // ''));

sub debug {
    say shift

}

[download]
the first call to debug() will generate a warning "Use of uninitialized value $y in concatenation..." The second call to debug() does not generate any warning, but it seems to be too complex. Another solution I was thinking about is probably even more complex: 
use 5.010;
use strict;
use warnings; 

my $x = 23;
my $y;

debug({x => $x, y => $y});

sub debug {
    my ($d) = @_;
    my $s = join ' ', map { sprintf("$_='%s'", ($d->{$_} // '')) } sor
+t keys %$d;
    say $s;
}

[download]
Another solution might be this: 
use 5.010;
use strict;
use warnings; 

my $x = 23;
my $y;

debug("x='%s' y='%s'", $x, $y);

sub debug {
    my ($fmt, @params) = @_;
    printf "$fmt\n", map { $_ // '' } @params;
}

[download]
Do you see any problems with the suggested solutions? Do you have any other suggestions?

In reply to use warnings and debug messages by szabgab

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