Now imagine several more "verify" type calls within that same eval.

Yeah, I figured it was something like that. Personally I still wouldn't use that "eval/die with a fixed string" pattern, and instead maybe wrap each call in an eval, or to make it look a little nicer, perhaps Try::Tiny. Of course, this being Perl, other ways come to mind :-) Say you've got a bunch of verify_* functions that you can't change and whose errors are fatal, but you want nonfatal versions of them:

use warnings;
use strict;

# UUT
use Scalar::Util qw/looks_like_number/;
sub verify_number {
    my ($arg) = @_;
    die "not a number" if !defined $arg;
    looks_like_number($arg) or die "not a number";
    return;
}

# wrap the funcs
my @funcs = qw/ verify_number /;
for my $f (@funcs) {
    my $orig = \&{$f};
    my $wrapped = sub { eval { $orig->(@_); 1 } };
    { no strict 'refs'; *{$f.'_nf'} = $wrapped }
}

use Test::More tests => 4;

# helper
sub exception (&)
    { eval { shift->(); 1 } ? undef : ($@ || die "\$@ was false") }

ok  !exception { verify_number("3.14") };
like exception { verify_number("foo")  }, qr/\bnot a number\b/i;

ok  verify_number_nf("3.14");
ok !verify_number_nf("foo");

[download]

Of course you don't need to install the wrapped versions into the symbol table, a hash would work fine too.

In reply to Re^4: Exiting eval via next: is that so bad? by haukex
in thread Exiting eval via next: is that so bad? by jplindstrom

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