my %rpi_v2_gpio_p1 = (
    3  => Device::BCM2835::RPI_V2_GPIO_P1_03,
    5  => Device::BCM2835::RPI_V2_GPIO_P1_05,
    7  => Device::BCM2835::RPI_V2_GPIO_P1_07,
    ...,
    40 => Device::BCM2835::RPI_V2_GPIO_P1_40,
);

##</code><code>##

my @rpi_v2_gpio_p1;
for ( @Device::BCM2835::EXPORT_OK ) {
   next if !/^RPI_V2_GPIO_P1_(\d+)\z/;
   my $pin = 0 + $1;
   my $val = do { no strict "refs"; "Device::BCM2835::$_"->() };
   $rpi_v2_gpio_p1[ $pin ] = $val;
}

##</code><code>##

my @rpi_v2_gpio_p1;
for ( @Device::BCM2835::EXPORT_OK ) {
   next if !/^RPI_V2_GPIO_P1_(\d+)\z/;
   my $pin = 0 + $1;
   my $val = ( \&{"Device::BCM2835::$_"} )->();
   $rpi_v2_gpio_p1[ $pin ] = $val;
}