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|
use 5.006001;
use strict;
use warnings;
package Example::Exporter;
# Inherit from Exporter::Tiny.
#
use base 'Exporter::Tiny';
# The list of functions to export by default.
# Be conservative.
#
our @EXPORT = qw( fib );
# The list of functions which are allowed to
# be exported. Be liberal.
#
our @EXPORT_OK = qw( embiggen );
# Note that there was no need to list "fib"
# in @EXPORT_OK. It was in @EXPORT, so it's
# implicitly ok.
# This is the definition of the "fib" function
# that we want to export.
#
sub fib {
my $n = $_[0];
(int($n) eq $n) && ($n >= 0)
or die "Expected natural number as argument; got '$n'";
return $n if $n < 2;
fib($n - 1) + fib($n - 2);
}
# We won't define a standard embiggen function.
# Instead we will generate one when requested.
#
sub _generate_embiggen {
my ($class, $name, $arg, $globals) = @_;
my $embiggen_amount = exists($arg->{amount}) ? $arg->{amount} : 1;
# This is the sub that will be installed into
# the caller's namespace.
#
return sub ($) {
my $n = $_[0];
return $n + $embiggen_amount;
}
}
1; # Make Perl Happy™
|
