package bignum;
require 5.005;
-$VERSION = '0.10';
+$VERSION = '0.13';
use Exporter;
-@ISA = qw( Exporter );
-@EXPORT_OK = qw( );
+@EXPORT_OK = qw( );
+@EXPORT = qw( inf NaN );
+@ISA = qw( Exporter );
use strict;
{
require Math::BigInt::Trace; $class = 'Math::BigInt::Trace';
$upgrade = 'Math::BigFloat::Trace';
-# print STDERR "Loading $class";
}
else
{
{
require Math::BigFloat::Trace; $class = 'Math::BigFloat::Trace';
$downgrade = 'Math::BigInt::Trace';
-# print STDERR "Loading $class";
}
else
{
print "Math::BigFloat\t\t v$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__
use bignum;
$x = 2 + 4.5,"\n"; # BigFloat 6.5
- print 2 ** 512 * 0.1; # really is what you think it is
+ 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
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 neccessary:
+
+ 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 $x might be something unexpected. Due to the
+transparent way of bignum C<ref()> should not be neccessary, anyway.
+
+Since Math::BigInt and BigFloat also overload the normal math operations,
+the following line will still work:
+
+ perl -Mbignum -le 'print ref(1234+1234)'
+
+Since numbers are actually objects, you can call all the usual methods from
+BigInt/BigFloat on them. This even works to some extent on expressions:
+
+ perl -Mbignum -le '$x = 1234; print $x->bdec()'
+ perl -Mbignum -le 'print 1234->binc();'
+ perl -Mbignum -le 'print 1234->binc->badd(6);'
+ perl -Mbignum -le 'print +(1234)->binc()'
+
+(Note that print doesn't do what you expect if the expression starts with
+'(' hence the C<+>)
+
+You can even chain the operations together as usual:
+
+ perl -Mbignum -le 'print 1234->binc->badd(6);'
+ 1241
+
+Under bignum (or bigint or bigrat), Perl will "upgrade" the numbers
+appropriately. This means that:
+
+ perl -Mbignum -le 'print 1234+4.5'
+ 1238.5
+
+will work correctly. These mixed cases don't do always work when using
+Math::BigInt or Math::BigFloat alone, or at least not in the way normal Perl
+scalars work.
+
+If you do want to work with large integers like under C<use integer;>, try
+C<use bigint;>:
+
+ perl -Mbigint -le 'print 1234.5+4.5'
+ 1238
+
+There is also C<use bigrat;> which gives you big rationals:
+
+ perl -Mbigrat -le 'print 1234+4.1'
+ 12381/10
+
+The entire upgrading/downgrading is still experimental and might not work
+as you expect or may even have bugs.
+
+You might get errors like this:
+
+ Can't use an undefined value as an ARRAY reference at
+ /usr/local/lib/perl5/5.8.0/Math/BigInt/Calc.pm line 864
+
+This means somewhere a routine got a BigFloat/Lite but expected a BigInt (or
+vice versa) and the upgrade/downgrad path was missing. This is a bug, please
+report it so that we can fix it.
+
+You might consider using just Math::BigInt or Math::BigFloat, since they
+allow you finer control over what get's done in which module/space. For
+instance, simple loop counters will be Math::BigInts under C<use bignum;> and
+this is slower than keeping them as Perl scalars:
+
+ perl -Mbignum -le 'for ($i = 0; $i < 10; $i++) { print ref($i); }'
+
+Please note the following does not work as expected (prints nothing), since
+overloading of '..' is not yet possible in Perl (as of v5.8.0):
+
+ perl -Mbignum -le 'for (1..2) { print ref($_); }'
+
=head2 OPTIONS
bignum recognizes some options that can be passed while loading it via use.
perl -Mbignum=v -e ''
+=head2 METHODS
+
+Beside import() and AUTOLOAD() there are only a few other methods.
+
+Since all numbers are now objects, you can use all functions that are part of
+the BigInt or BigFloat API. It is wise to use only the bxxx() notation, and not
+the fxxx() notation, though. This makes it possible that the underlying object
+might morph into a different class than BigFloat.
+
+=over 2
+
+=item inf()
+
+A shortcut to return Math::BigInt->binf(). Usefull because Perl does not always
+handle bareword C<inf> properly.
+
+=item NaN()
+
+A shortcut to return Math::BigInt->bnan(). Usefull because Perl does not always
+handle bareword C<NaN> properly.
+
+=item upgrade()
+
+Return the class that numbers are upgraded to, is in fact returning
+C<$Math::BigInt::upgrade>.
+
+=back
+
=head2 MATH LIBRARY
Math with the numbers is done (by default) by a module called
minus infinity. You will get '+inf' when dividing a positive number by 0, and
'-inf' when dividing any negative number by 0.
-=head2 METHODS
-
-Since all numbers are now objects, you can use all functions that are part of
-the BigInt or BigFloat API. It is wise to use only the bxxx() notation, and not
-the fxxx() notation, though. This makes it possible that the underlying object
-might morph into a different class than BigFloat.
-
=head1 MODULES USED
C<bignum> is just a thin wrapper around various modules of the Math::BigInt
https://perl5.git.perl.org / perl5.git / blobdiff