package bignum;
use 5.006;
$VERSION = '0.23';
use Exporter;
@ISA = qw( bigint );
@EXPORT_OK = qw( PI e bexp bpi );
@EXPORT = qw( inf NaN );
use strict;
use overload;
require bigint; # no "use" to avoid import being called
##############################################################################
BEGIN
{
*inf = \&bigint::inf;
*NaN = \&bigint::NaN;
}
# These are all alike, and thus faked by AUTOLOAD
my @faked = qw/round_mode accuracy precision div_scale/;
use vars qw/$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 unimport
{
$^H{bignum} = undef; # no longer in effect
overload::remove_constant('binary','','float','','integer');
}
sub in_effect
{
my $level = shift || 0;
my $hinthash = (caller($level))[10];
$hinthash->{bignum};
}
#############################################################################
# the following two routines are for Perl 5.9.4 or later and are lexical
sub _hex
{
return CORE::hex($_[0]) unless in_effect(1);
my $i = $_[0];
$i = '0x'.$i unless $i =~ /^0x/;
Math::BigInt->new($i);
}
sub _oct
{
return CORE::oct($_[0]) unless in_effect(1);
my $i = $_[0];
return Math::BigInt->from_oct($i) if $i =~ /^0[0-7]/;
Math::BigInt->new($i);
}
sub import
{
my $self = shift;
$^H{bignum} = 1; # we are in effect
my ($hex,$oct);
# for newer Perls override hex() and oct() with a lexical version:
if ($] > 5.009003)
{
$hex = \&_hex;
$oct = \&_oct;
}
# some defaults
my $lib = ''; my $lib_kind = 'try';
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; $i++;
}
elsif ($_[$i] =~ /^(l|lib|try|only)$/)
{
# this causes a different low lib to take care...
$lib_kind = $1; $lib_kind = 'lib' if $lib_kind eq 'l';
$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; $j --;
}
elsif ($_[$i] eq 'hex')
{
splice @a, $j, 1; $j --;
$hex = \&bigint::_hex_global;
}
elsif ($_[$i] eq 'oct')
{
splice @a, $j, 1; $j --;
$oct = \&bigint::_oct_global;
}
elsif ($_[$i] !~ /^(PI|e|bexp|bpi)\z/)
{
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_kind => $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$Math::BigFloat::VERSION\n";
exit;
}
# Take care of octal/hexadecimal constants
overload::constant binary => sub { bigint::_binary_constant(shift) };
# if another big* was already loaded:
my ($package) = caller();
no strict 'refs';
if (!defined *{"${package}::inf"})
{
$self->export_to_level(1,$self,@a); # export inf and NaN
}
{
no warnings 'redefine';
*CORE::GLOBAL::oct = $oct if $oct;
*CORE::GLOBAL::hex = $hex if $hex;
}
}
sub PI () { Math::BigFloat->new('3.141592653589793238462643383279502884197'); }
sub e () { Math::BigFloat->new('2.718281828459045235360287471352662497757'); }
sub bpi ($) { Math::BigFloat::bpi(@_); }
sub bexp ($$) { my $x = Math::BigFloat->new($_[0]); $x->bexp($_[1]); }
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
{
no bignum;
print 2 ** 256,"\n"; # a normal Perl scalar now
}
# for older Perls, note that this will be global:
use bignum qw/hex oct/;
print hex("0x1234567890123490"),"\n";
print oct("01234567890123490"),"\n";
=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->copy()->binc();'
perl -Mbignum -le 'print 1234->copy()->binc->badd(6);'
perl -Mbignum -le 'print +(1234)->copy()->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->copy()->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