package bignum;
require 5.005;
$VERSION = '0.17';
use Exporter;
@EXPORT_OK = qw( );
@EXPORT = qw( inf NaN );
@ISA = qw( Exporter );
use strict;
##############################################################################
# These are all alike, and thus faked by AUTOLOAD
my @faked = qw/round_mode accuracy precision div_scale/;
use vars qw/$VERSION $AUTOLOAD $_lite/; # _lite for testsuite
sub AUTOLOAD
{
my $name = $AUTOLOAD;
$name =~ s/.*:://; # split package
no strict 'refs';
foreach my $n (@faked)
{
if ($n eq $name)
{
*{"bignum::$name"} = sub
{
my $self = shift;
no strict 'refs';
if (defined $_[0])
{
Math::BigInt->$name($_[0]);
return Math::BigFloat->$name($_[0]);
}
return Math::BigInt->$name();
};
return &$name;
}
}
# delayed load of Carp and avoid recursion
require Carp;
Carp::croak ("Can't call bignum\-\>$name, not a valid method");
}
sub upgrade
{
my $self = shift;
no strict 'refs';
# if (defined $_[0])
# {
# $Math::BigInt::upgrade = $_[0];
# $Math::BigFloat::upgrade = $_[0];
# }
return $Math::BigInt::upgrade;
}
sub import
{
my $self = shift;
# some defaults
my $lib = '';
my $upgrade = 'Math::BigFloat';
my $downgrade = 'Math::BigInt';
my @import = ( ':constant' ); # drive it w/ constant
my @a = @_; my $l = scalar @_; my $j = 0;
my ($ver,$trace); # version? trace?
my ($a,$p); # accuracy, precision
for ( my $i = 0; $i < $l ; $i++,$j++ )
{
if ($_[$i] eq 'upgrade')
{
# this causes upgrading
$upgrade = $_[$i+1]; # or undef to disable
my $s = 2; $s = 1 if @a-$j < 2; # avoid "can not modify non-existant..."
splice @a, $j, $s; $j -= $s; $i++;
}
elsif ($_[$i] eq 'downgrade')
{
# this causes downgrading
$downgrade = $_[$i+1]; # or undef to disable
my $s = 2; $s = 1 if @a-$j < 2; # avoid "can not modify non-existant..."
splice @a, $j, $s; $j -= $s; $i++;
}
elsif ($_[$i] =~ /^(l|lib)$/)
{
# this causes a different low lib to take care...
$lib = $_[$i+1] || '';
my $s = 2; $s = 1 if @a-$j < 2; # avoid "can not modify non-existant..."
splice @a, $j, $s; $j -= $s; $i++;
}
elsif ($_[$i] =~ /^(a|accuracy)$/)
{
$a = $_[$i+1];
my $s = 2; $s = 1 if @a-$j < 2; # avoid "can not modify non-existant..."
splice @a, $j, $s; $j -= $s; $i++;
}
elsif ($_[$i] =~ /^(p|precision)$/)
{
$p = $_[$i+1];
my $s = 2; $s = 1 if @a-$j < 2; # avoid "can not modify non-existant..."
splice @a, $j, $s; $j -= $s; $i++;
}
elsif ($_[$i] =~ /^(v|version)$/)
{
$ver = 1;
splice @a, $j, 1; $j --;
}
elsif ($_[$i] =~ /^(t|trace)$/)
{
$trace = 1;
splice @a, $j, 1; $j --;
}
else { die "unknown option $_[$i]"; }
}
my $class;
$_lite = 0; # using M::BI::L ?
if ($trace)
{
require Math::BigInt::Trace; $class = 'Math::BigInt::Trace';
$upgrade = 'Math::BigFloat::Trace';
}
else
{
# see if we can find Math::BigInt::Lite
if (!defined $a && !defined $p) # rounding won't work to well
{
eval 'require Math::BigInt::Lite;';
if ($@ eq '')
{
@import = ( ); # :constant in Lite, not MBI
Math::BigInt::Lite->import( ':constant' );
$_lite= 1; # signal okay
}
}
require Math::BigInt if $_lite == 0; # not already loaded?
$class = 'Math::BigInt'; # regardless of MBIL or not
}
push @import, 'lib' => $lib if $lib ne '';
# Math::BigInt::Trace or plain Math::BigInt
$class->import(@import, upgrade => $upgrade);
if ($trace)
{
require Math::BigFloat::Trace; $class = 'Math::BigFloat::Trace';
$downgrade = 'Math::BigInt::Trace';
}
else
{
require Math::BigFloat; $class = 'Math::BigFloat';
}
$class->import(':constant','downgrade',$downgrade);
bignum->accuracy($a) if defined $a;
bignum->precision($p) if defined $p;
if ($ver)
{
print "bignum\t\t\t v$VERSION\n";
print "Math::BigInt::Lite\t v$Math::BigInt::Lite::VERSION\n" if $_lite;
print "Math::BigInt\t\t v$Math::BigInt::VERSION";
my $config = Math::BigInt->config();
print " lib => $config->{lib} v$config->{lib_version}\n";
print "Math::BigFloat\t\t v$Math::BigFloat::VERSION\n";
exit;
}
$self->export_to_level(1,$self,@a); # export inf and NaN
}
sub inf () { Math::BigInt->binf(); }
sub NaN () { Math::BigInt->bnan(); }
1;
__END__
=head1 NAME
bignum - Transparent BigNumber support for Perl
=head1 SYNOPSIS
use bignum;
$x = 2 + 4.5,"\n"; # BigFloat 6.5
print 2 ** 512 * 0.1,"\n"; # really is what you think it is
print inf * inf,"\n"; # prints inf
print NaN * 3,"\n"; # prints NaN
=head1 DESCRIPTION
All operators (including basic math operations) are overloaded. Integer and
floating-point constants are created as proper BigInts or BigFloats,
respectively.
If you do
use bignum;
at the top of your script, Math::BigFloat and Math::BigInt will be loaded
and any constant number will be converted to an object (Math::BigFloat for
floats like 3.1415 and Math::BigInt for integers like 1234).
So, the following line:
$x = 1234;
creates actually a Math::BigInt and stores a reference to in $x.
This happens transparently and behind your back, so to speak.
You can see this with the following:
perl -Mbignum -le 'print ref(1234)'
Don't worry if it says Math::BigInt::Lite, bignum and friends will use Lite
if it is installed since it is faster for some operations. It will be
automatically upgraded to BigInt whenever necessary:
perl -Mbignum -le 'print ref(2**255)'
This also means it is a bad idea to check for some specific package, since
the actual contents of $x might be something unexpected. Due to the
transparent way of bignum C[ should not be necessary, anyway.
Since Math::BigInt and BigFloat also overload the normal math operations,
the following line will still work:
perl -Mbignum -le 'print ref(1234+1234)'
Since numbers are actually objects, you can call all the usual methods from
BigInt/BigFloat on them. This even works to some extent on expressions:
perl -Mbignum -le '$x = 1234; print $x->bdec()'
perl -Mbignum -le 'print 1234->binc();'
perl -Mbignum -le 'print 1234->binc->badd(6);'
perl -Mbignum -le 'print +(1234)->binc()'
(Note that print doesn't do what you expect if the expression starts with
'(' hence the C<+>)
You can even chain the operations together as usual:
perl -Mbignum -le 'print 1234->binc->badd(6);'
1241
Under bignum (or bigint or bigrat), Perl will "upgrade" the numbers
appropriately. This means that:
perl -Mbignum -le 'print 1234+4.5'
1238.5
will work correctly. These mixed cases don't do always work when using
Math::BigInt or Math::BigFloat alone, or at least not in the way normal Perl
scalars work.
If you do want to work with large integers like under C]