package bigint;
-require 5.005;
+use 5.006002;
-$VERSION = '0.06';
+$VERSION = '0.22';
use Exporter;
@ISA = qw( Exporter );
-@EXPORT_OK = qw( );
+@EXPORT_OK = qw( PI e );
@EXPORT = qw( inf NaN );
use strict;
sub upgrade
{
- my $self = shift;
- no strict 'refs';
-# if (defined $_[0])
-# {
-# $Math::BigInt::upgrade = $_[0];
-# }
- return $Math::BigInt::upgrade;
+ $Math::BigInt::upgrade;
+ }
+
+sub _binary_constant
+ {
+ # this takes a binary/hexadecimal/octal constant string and returns it
+ # as string suitable for new. Basically it converts octal to decimal, and
+ # passes every thing else unmodified back.
+ my $string = shift;
+
+ return Math::BigInt->new($string) if $string =~ /^0[bx]/;
+
+ # so it must be an octal constant
+ Math::BigInt->from_oct($string);
}
-sub _constant
+sub _float_constant
{
# this takes a floating point constant string and returns it truncated to
# integer. For instance, '4.5' => '4', '1.234e2' => '123' etc
return $sign.$$miv.$$mfv.'E'.$ec; # 123.45e+3 => 12345e1
}
$mfv = substr($$mfv,0,$ec);
- return $sign.$$miv.$mfv; # 123.45e+1 => 1234
+ $sign.$$miv.$mfv; # 123.45e+1 => 1234
+ }
+
+sub unimport
+ {
+ $^H{bigint} = undef; # no longer in effect
+ overload::remove_constant('binary','','float','','integer');
+ }
+
+sub in_effect
+ {
+ my $level = shift || 0;
+ my $hinthash = (caller($level))[10];
+ $hinthash->{bigint};
+ }
+
+#############################################################################
+# the following two routines are for "use bigint qw/hex oct/;":
+
+sub _hex_global
+ {
+ my $i = $_[0];
+ $i = '0x'.$i unless $i =~ /^0x/;
+ Math::BigInt->new($i);
+ }
+
+sub _oct_global
+ {
+ my $i = $_[0];
+ return Math::BigInt->from_oct($i) if $i =~ /^0[0-7]/;
+ Math::BigInt->new($i);
+ }
+
+#############################################################################
+# 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;
+ $^H{bigint} = 1; # we are in effect
+
+ my ($hex,$oct);
+ # for newer Perls always override hex() and oct() with a lexical version:
+ if ($] > 5.009004)
+ {
+ $oct = \&_oct;
+ $hex = \&_hex;
+ }
# some defaults
- my $lib = 'Calc';
+ my $lib = ''; my $lib_kind = 'try';
my @import = ( ':constant' ); # drive it w/ constant
my @a = @_; my $l = scalar @_; my $j = 0;
my ($a,$p); # accuracy, precision
for ( my $i = 0; $i < $l ; $i++,$j++ )
{
- if ($_[$i] =~ /^(l|lib)$/)
+ if ($_[$i] =~ /^(l|lib|try|only)$/)
{
# 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++;
$trace = 1;
splice @a, $j, 1; $j --;
}
- else { die "unknown option $_[$i]"; }
+ elsif ($_[$i] eq 'hex')
+ {
+ splice @a, $j, 1; $j --;
+ $hex = \&_hex_global;
+ }
+ elsif ($_[$i] eq 'oct')
+ {
+ splice @a, $j, 1; $j --;
+ $oct = \&_oct_global;
+ }
+ elsif ($_[$i] !~ /^(PI|e)\z/)
+ {
+ die ("unknown option $_[$i]");
+ }
}
my $class;
$_lite = 0; # using M::BI::L ?
}
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, lib => $lib);
+ $class->import(@import);
bigint->accuracy($a) if defined $a;
bigint->precision($p) if defined $p;
}
# we take care of floating point constants, since BigFloat isn't available
# and BigInt doesn't like them:
- overload::constant float => sub { Math::BigInt->new( _constant(shift) ); };
+ overload::constant float => sub { Math::BigInt->new( _float_constant(shift) ); };
+ # Take care of octal/hexadecimal constants
+ overload::constant binary => sub { _binary_constant(shift) };
+
+ # if another big* was already loaded:
+ my ($package) = caller();
- $self->export_to_level(1,$self,@a); # export inf and NaN
+ no strict 'refs';
+ if (!defined *{"${package}::inf"})
+ {
+ $self->export_to_level(1,$self,@a); # export inf and NaN, e and PI
+ }
+ {
+ no warnings 'redefine';
+ *CORE::GLOBAL::oct = $oct if $oct;
+ *CORE::GLOBAL::hex = $hex if $hex;
+ }
}
-sub inf () { Math::BigInt->binf(); }
-sub NaN () { Math::BigInt->bnan(); }
+sub inf () { Math::BigInt::binf(); }
+sub NaN () { Math::BigInt::bnan(); }
+sub PI { Math::BigInt->new(3); }
+sub e { Math::BigInt->new(2); }
1;
print 2 ** 512,"\n"; # really is what you think it is
print inf + 42,"\n"; # inf
print NaN * 7,"\n"; # NaN
+ print hex("0x1234567890123490"),"\n"; # Perl v5.9.4 or later
+
+ {
+ no bigint;
+ print 2 ** 256,"\n"; # a normal Perl scalar now
+ }
+
+ # Note that this will be global:
+ use bigint qw/hex oct/;
+ print hex("0x1234567890123490"),"\n";
+ print oct("01234567890123490"),"\n";
=head1 DESCRIPTION
All operators (including basic math operations) are overloaded. Integer
constants are created as proper BigInts.
-Floating point constants are truncated to integer. All results are also
-truncated.
+Floating point constants are truncated to integer. All parts and results of
+expressions are also truncated.
+
+Unlike L<integer>, this pragma creates integer constants that are only
+limited in their size by the available memory and CPU time.
+
+=head2 use integer vs. use bigint
+
+There is one small difference between C<use integer> and C<use bigint>: the
+former will not affect assignments to variables and the return value of
+some functions. C<bigint> truncates these results to integer too:
+
+ # perl -Minteger -wle 'print 3.2'
+ 3.2
+ # perl -Minteger -wle 'print 3.2 + 0'
+ 3
+ # perl -Mbigint -wle 'print 3.2'
+ 3
+ # perl -Mbigint -wle 'print 3.2 + 0'
+ 3
+
+ # perl -Mbigint -wle 'print exp(1) + 0'
+ 2
+ # perl -Mbigint -wle 'print exp(1)'
+ 2
+ # perl -Minteger -wle 'print exp(1)'
+ 2.71828182845905
+ # perl -Minteger -wle 'print exp(1) + 0'
+ 2
+
+In practice this makes seldom a difference as B<parts and results> of
+expressions will be truncated anyway, but this can, for instance, affect the
+return value of subroutines:
+
+ sub three_integer { use integer; return 3.2; }
+ sub three_bigint { use bigint; return 3.2; }
+
+ print three_integer(), " ", three_bigint(),"\n"; # prints "3.2 3"
=head2 Options
perl -Mbigint=a,2 -le 'print 12345+1'
+Note that setting precision and accurary at the same time is not possible.
+
=item p or precision
This sets the precision for all math operations. The argument can be any
perl -Mbignum=p,5 -le 'print 123456789+123'
+Note that setting precision and accurary at the same time is not possible.
+
=item t or trace
This enables a trace mode and is primarily for debugging bigint or
Math::BigInt.
-=item l or lib
+=item hex
+
+Override the build-in hex() method with a version that can handle big
+integers. Note that under Perl v5.9.4 or ealier, this will be global
+and cannot be disabled with "no bigint;".
+
+=item oct
+
+Override the build-in oct() method with a version that can handle big
+integers. Note that under Perl v5.9.4 or ealier, this will be global
+and cannot be disabled with "no bigint;".
+
+=item l, lib, try or only
-Load a different math lib, see L<MATH LIBRARY>.
+Load a different math lib, see L<Math Library>.
- perl -Mbigint=l,GMP -e 'print 2 ** 512'
+ perl -Mbigint=lib,GMP -e 'print 2 ** 512'
+ perl -Mbigint=try,GMP -e 'print 2 ** 512'
+ perl -Mbigint=only,GMP -e 'print 2 ** 512'
Currently there is no way to specify more than one library on the command
-line. This will be hopefully fixed soon ;)
+line. This means the following does not work:
+
+ perl -Mbignum=l,GMP,Pari -e 'print 2 ** 512'
+
+This will be hopefully fixed soon ;)
=item v or version
perl -Mbigint=v
+=back
+
=head2 Math Library
Math with the numbers is done (by default) by a module called
You can change this by using:
- use bigint lib => 'BitVect';
+ use bignum lib => 'GMP';
The following would first try to find Math::BigInt::Foo, then
Math::BigInt::Bar, and when this also fails, revert to Math::BigInt::Calc:
use bigint lib => 'Foo,Math::BigInt::Bar';
+Using C<lib> warns if none of the specified libraries can be found and
+L<Math::BigInt> did fall back to one of the default libraries.
+To supress this warning, use C<try> instead:
+
+ use bignum try => 'GMP';
+
+If you want the code to die instead of falling back, use C<only> instead:
+
+ use bignum only => 'GMP';
+
Please see respective module documentation for further details.
=head2 Internal Format
the BigInt API. You can only use the bxxx() notation, and not the fxxx()
notation, though.
+=over 2
+
+=item inf()
+
+A shortcut to return Math::BigInt->binf(). Useful because Perl does not always
+handle bareword C<inf> properly.
+
+=item NaN()
+
+A shortcut to return Math::BigInt->bnan(). Useful because Perl does not always
+handle bareword C<NaN> properly.
+
+=item e()
+
+Returns Euler's number C<e>, aka exp(1), to the given number of digits.
+
+=item PI()
+
+Returns PI to the given number of digits.
+
+=item upgrade()
+
+Return the class that numbers are upgraded to, is in fact returning
+C<$Math::BigInt::upgrade>.
+
+=item in_effect()
+
+ use bigint;
+
+ print "in effect\n" if bigint::in_effect; # true
+ {
+ no bigint;
+ print "in effect\n" if bigint::in_effect; # false
+ }
+
+Returns true or false if C<bigint> is in effect in the current scope.
+
+This method only works on Perl v5.9.4 or later.
+
+=back
+
+=head2 MATH LIBRARY
+
+Math with the numbers is done (by default) by a module called
+
=head2 Caveat
But a warning is in order. When using the following to make a copy of a number,
print $x + 1, " ", $y,"\n"; # prints 10 9
but calling any method that modifies the number directly will result in
-B<both> the original and the copy beeing destroyed:
+B<both> the original and the copy being destroyed:
$x = 9; $y = $x;
print $x->badd(1), " ", $y,"\n"; # prints 10 10
See the documentation about the copy constructor and C<=> in overload, as
well as the documentation in BigInt for further details.
+=head1 CAVAETS
+
+=over 2
+
+=item in_effect()
+
+This method only works on Perl v5.9.4 or later.
+
+=item hex()/oct()
+
+C<bigint> overrides these routines with versions that can also handle
+big integer values. Under Perl prior to version v5.9.4, however, this
+will not happen unless you specifically ask for it with the two
+import tags "hex" and "oct" - and then it will be global and cannot be
+disabled inside a scope with "no bigint":
+
+ use bigint qw/hex oct/;
+
+ print hex("0x1234567890123456");
+ {
+ no bigint;
+ print hex("0x1234567890123456");
+ }
+
+The second call to hex() will warn about a non-portable constant.
+
+Compare this to:
+
+ use bigint;
+
+ # will warn only under Perl older than v5.9.4
+ print hex("0x1234567890123456");
+
+=back
+
=head1 MODULES USED
C<bigint> is just a thin wrapper around various modules of the Math::BigInt
perl -Mbigint -le 'print log(2)'
perl -Mbigint -le 'print 2 ** 0.5'
perl -Mbigint=a,65 -le 'print 2 ** 0.2'
+ perl -Mbignum=a,65,l,GMP -le 'print 7 ** 7777'
=head1 LICENSE
=head1 AUTHORS
-(C) by Tels L<http://bloodgate.com/> in early 2002 - 2005.
+(C) by Tels L<http://bloodgate.com/> in early 2002 - 2007.
=cut
https://perl5.git.perl.org / perl5.git / blobdiff