package Angle;
use strict; use warnings;

use constant PI => 4*atan2( 1, 1);
use constant RAD => 180/PI;

sub cre { bless \ my $angle, shift }
sub new {
    my $class = shift;
    $class->Angle::cre->Angle::init( @_);
}

sub init {
    my $obj = shift;
    $$obj = _get_angle( @_);
    $obj;
}

sub rad { ${ shift() } };
sub deg { ${ shift() }*RAD }

sub _get_angle {
    my $angle;
    if ( @_ == 1 ) {
        $angle = shift;
    } else {
        my %spec = @_;
        $angle = exists $spec{ deg} ?  $spec{ deg}/RAD : $spec{ rad};
    }
    modulo( $angle, 2*PI);
}

use POSIX;
sub modulo {
    my ( $x, $y) = @_;
    $y ? $x - $y*POSIX::floor( $x/$y) : $x;
}

1;