Argthtjtr

I already use a Perl package (Funx.pm) for reusable code. But I'd like it to include a bunch of scalars as return values, i.e.

my $SUCCESS         =   0;

my $NOFILE      =   1;

my $COPYFAIL        =   2;

my $APPRUNNING      =   3;

...and on and on....

Is there a way to do so and be able to just use the variables without have to import each one nor having to use Funx:: when using them?

Thanks

Prefacing this by saying that it is a bad idea, imagine if someone sets a different value to $SUCCESS anywhere in the code base. Using $Funx::SUCCESS is a much better way to go, it also provides context as to what is the success of.

our() makes a variable visible across all scopes, including across packages.

package Funx;

our($SUCCESS, $NOFILE, $COPYFAIL, $APPRUNNING);

$SUCCESS         =   0;

$NOFILE      =   1;

$COPYFAIL        =   2;

$APPRUNNING      =   3;



package main;

say($SUCCESS, $Funx::SUCCESS); # both work

Here's an example of a module that exports constants.

package RPi::Const;



use strict;

use warnings;



our $VERSION = '1.04';



require Exporter;

use base qw( Exporter );

our @EXPORT_OK = ();

our %EXPORT_TAGS = ( all => @EXPORT_OK );



use constant {

    RPI_MODE_WPI => 0,

    RPI_MODE_GPIO => 1,

    RPI_MODE_GPIO_SYS => 2,

    RPI_MODE_PHYS => 3,

    RPI_MODE_UNINIT => -1,

};



{ # mode



    my @const = qw(

        RPI_MODE_WPI

        RPI_MODE_GPIO

        RPI_MODE_GPIO_SYS

        RPI_MODE_PHYS

        RPI_MODE_UNINIT

    );



    push @EXPORT_OK, @const;

    $EXPORT_TAGS{mode} = @const;

}



use constant {

    MCP23017_IODIRA     => 0x00,

    MCP23017_IODIRB     => 0x01,

    MCP23017_IPOLA      => 0x02,

    MCP23017_IPOLB      => 0x03,

    MCP23017_GPINTENA   => 0x04,

    MCP23017_GPINTENB   => 0x05,

    MCP23017_DEFVALA    => 0x06,

    MCP23017_DEFVALB    => 0x07,

    MCP23017_INTCONA    => 0x08,

    MCP23017_INTCONB    => 0x09,

    MCP23017_IOCONA     => 0x0A,

    MCP23017_IOCONB     => 0x0B,

    MCP23017_GPPUA      => 0x0C,

    MCP23017_GPPUB      => 0x0D,

    MCP23017_INTFA      => 0x0E,

    MCP23017_INTFB      => 0x0F,

    MCP23017_INTCAPA    => 0x10,

    MCP23017_INTCAPB    => 0x11,

    MCP23017_GPIOA      => 0x12,

    MCP23017_GPIOB      => 0x13,

    MCP23017_OLATA      => 0x14,

    MCP23017_OLATB      => 0x15,



    MCP23017_INPUT      => 1,

    MCP23017_OUTPUT     => 0,

};



{ # MCP23017 GPIO Expander Registers



    my @const = qw(

        MCP23017_IODIRA

        MCP23017_IODIRB

        MCP23017_IPOLA

        MCP23017_IPOLB

        MCP23017_GPINTENA

        MCP23017_GPINTENB

        MCP23017_DEFVALA

        MCP23017_DEFVALB

        MCP23017_INTCONA

        MCP23017_INTCONB

        MCP23017_IOCONA

        MCP23017_IOCONB

        MCP23017_GPPUA

        MCP23017_GPPUB

        MCP23017_INTFA

        MCP23017_INTFB

        MCP23017_INTCAPA

        MCP23017_INTCAPB

        MCP23017_GPIOA

        MCP23017_GPIOB

        MCP23017_OLATA

        MCP23017_OLATB

        MCP23017_INPUT

        MCP23017_OUTPUT

    );



    push @EXPORT_OK, @const;

    $EXPORT_TAGS{mcp23017_registers} = @const;

}



1;

__END__

In your calling scripts, you can import each bundle (tag), or by using the :all tag, you can import all the separate groups:

use RPi::Const qw(:mcp23017_registers); # single grouping

...or

use RPi::Const qw(:all); # all groupings

Then you can use any of the imported constants:

sub mode {

    my ($self, $pin, $mode) = @_;



    if (! defined $mode){

        my $reg = $pin > 7 ? MCP23017_IODIRB : MCP23017_IODIRA;

        my $bit = _pinBit($pin);

        return getRegisterBit($self->_fd, $reg, $bit);

    }



    _check_mode($mode);



    pinMode($self->_fd, $pin, $mode);

}