package bigint;
use 5.006002;
-$VERSION = '0.10';
+$VERSION = '0.22';
use Exporter;
@ISA = qw( Exporter );
-@EXPORT_OK = qw( );
-@EXPORT = qw( inf NaN );
+@EXPORT_OK = qw( PI e bpi bexp );
+@EXPORT = qw( inf NaN );
use strict;
use overload;
sub upgrade
{
- my $self = shift;
- no strict 'refs';
-# if (defined $_[0])
-# {
-# $Math::BigInt::upgrade = $_[0];
-# }
$Math::BigInt::upgrade;
}
$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+ $^H{bigint} = undef; # no longer in effect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 = ''; my $lib_kind = 'try';
$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|bpi|bexp)\z/)
+ {
+ die ("unknown option $_[$i]");
+ }
}
my $class;
$_lite = 0; # using M::BI::L ?
# Take care of octal/hexadecimal constants
overload::constant binary => sub { _binary_constant(shift) };
- $self->export_to_level(1,$self,@a); # export inf and NaN
+ # 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, 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); }
+sub bpi ($) { Math::BigInt->new(3); }
+sub bexp ($$) { my $x = Math::BigInt->new($_[0]); $x->bexp($_[1]); }
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
This enables a trace mode and is primarily for debugging bigint or
Math::BigInt.
+=item hex
+
+Override the built-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 built-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>.
A shortcut to return Math::BigInt->bnan(). Useful because Perl does not always
handle bareword C<NaN> properly.
+=item e
+
+ # perl -Mbigint=e -wle 'print e'
+
+Returns Euler's number C<e>, aka exp(1). Note that under bigint, this is
+truncated to an integer, and hence simple '2'.
+
+=item PI
+
+ # perl -Mbigint=PI -wle 'print PI'
+
+Returns PI. Note that under bigint, this is truncated to an integer, and hence
+simple '3'.
+
+=item bexp()
+
+ bexp($power,$accuracy);
+
+Returns Euler's number C<e> raised to the appropriate power, to
+the wanted accuracy.
+
+Note that under bigint, the result is truncated to an integer.
+
+Example:
+
+ # perl -Mbigint=bexp -wle 'print bexp(1,80)'
+
+=item bpi()
+
+ bpi($accuracy);
+
+Returns PI to the wanted accuracy. Note that under bigint, this is truncated
+to an integer, and hence simple '3'.
+
+Example:
+
+ # perl -Mbigint=bpi -wle 'print bpi(80)'
+
=item upgrade()
Return the class that numbers are upgraded to, is in fact returning
C<$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
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
https://perl5.git.perl.org / perl5.git / blobdiff