[perl5.git] / lib / bigrat.pm

package bigrat;
require 5.005;

$VERSION = '0.06';
use Exporter;
@ISA		= qw( Exporter );
@EXPORT_OK	= qw( ); 
@EXPORT		= qw( inf NaN ); 

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 $name)
      {
      *{"bigrat::$name"} = sub 
        {
        my $self = shift;
        no strict 'refs';
        if (defined $_[0])
          {
          Math::BigInt->$name($_[0]);
          Math::BigFloat->$name($_[0]);
          return Math::BigRat->$name($_[0]);
          }
        return Math::BigInt->$name();
        };
      return &$name;
      }
    }
 
  # delayed load of Carp and avoid recursion
  require Carp;
  Carp::croak ("Can't call bigrat\-\>$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;

  # see also bignum->import() for additional comments

  # some defaults
  my $lib = 'Calc'; my $upgrade = 'Math::BigFloat';

  my @import = ( ':constant' );				# drive it w/ constant
  my @a = @_; my $l = scalar @_; my $j = 0;
  my ($a,$p);
  my ($ver,$trace);					# version? trace?
  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 -= $s;
      }
    elsif ($_[$i] =~ /^(l|lib)$/)
      {
      # 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 -= $s;
      }
    elsif ($_[$i] =~ /^(v|version)$/)
      {
      $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
    }
  # Math::BigInt::Trace or plain Math::BigInt
  $class->import(@import, upgrade => $upgrade, lib => $lib);

  require Math::BigFloat;
  Math::BigFloat->import( upgrade => 'Math::BigRat', ':constant' );
  require Math::BigRat;
  if ($ver)
    {
    print "bigrat\t\t\t v$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$Math::BigFloat::VERSION\n";
    print "Math::BigRat\t\t v$Math::BigRat::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

bigrat - Transparent BigNumber/BigRationale support for Perl

=head1 SYNOPSIS

  use bigrat;

  $x = 2 + 4.5,"\n";			# BigFloat 6.5
  print 1/3 + 1/4,"\n";			# produces 7/12

=head1 DESCRIPTION

All operators (inlcuding basic math operations) are overloaded. Integer and
floating-point constants are created as proper BigInts or BigFloats,
respectively.

Other than L<bignum>, this module upgrades to Math::BigRat, meaning that
instead of 2.5 you will get 2+1/2 as output.

=head2 MODULES USED

C<bigrat> is just a thin wrapper around various modules of the Math::BigInt
family. Think of it as the head of the family, who runs the shop, and orders
the others to do the work.

The following modules are currently used by bignum:

        Math::BigInt::Lite      (for speed, and only if it is loadable)
        Math::BigInt
        Math::BigFloat
        Math::BigRat

=head2 MATH LIBRARY

Math with the numbers is done (by default) by a module called
Math::BigInt::Calc. This is equivalent to saying:

	use bigrat lib => 'Calc';

You can change this by using:

	use bigrat lib => 'BitVect';

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 bigrat lib => 'Foo,Math::BigInt::Bar';

Please see respective module documentation for further details.

=head2 SIGN

The sign is either '+', '-', 'NaN', '+inf' or '-inf' and stored seperately.

A sign of 'NaN' is used to represent the result when input arguments are not
numbers or as a result of 0/0. '+inf' and '-inf' represent plus respectively
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 not 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 you independed on the fact that the
underlying object might morph into a different class than BigFloat.

=head2 CAVEAT

But a warning is in order. When using the following to make a copy of a number,
only a shallow copy will be made.

        $x = 9; $y = $x;
        $x = $y = 7;

Using the copy or the original with overloaded math is okay, e.g. the
following work:

        $x = 9; $y = $x;
        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:

        $x = 9; $y = $x;
        print $x->badd(1), " ", $y,"\n";        # prints 10 10

        $x = 9; $y = $x;
        print $x->binc(1), " ", $y,"\n";        # prints 10 10

        $x = 9; $y = $x;
        print $x->bmul(2), " ", $y,"\n";        # prints 18 18

Using methods that do not modify, but testthe contents works:

        $x = 9; $y = $x;
        $z = 9 if $x->is_zero();                # works fine

See the documentation about the copy constructor and C<=> in overload, as
well as the documentation in BigInt for further details.

=head1 EXAMPLES
 
	perl -Mbigrat -le 'print sqrt(33)'
	perl -Mbigrat -le 'print 2*255'
	perl -Mbigrat -le 'print 4.5+2*255'
	perl -Mbigrat -le 'print 3/7 + 5/7 + 8/3'	
	perl -Mbigrat -le 'print 12->is_odd()';

=head1 LICENSE

This program is free software; you may redistribute it and/or modify it under
the same terms as Perl itself.

=head1 SEE ALSO

Especially L<bignum>.

L<Math::BigFloat>, L<Math::BigInt>, L<Math::BigRat> and L<Math::Big> as well
as L<Math::BigInt::BitVect>, L<Math::BigInt::Pari> and  L<Math::BigInt::GMP>.

=head1 AUTHORS

(C) by Tels L<http://bloodgate.com/> in early 2002.

=cut
Commit	Line	Data
126f3c5f JH	1	package bigrat;
	2	require 5.005;
	3
990fb837	4	$VERSION = '0.06';
126f3c5f	5	use Exporter;
b4bc5691 T	6	@ISA = qw( Exporter );
	7	@EXPORT_OK = qw( );
	8	@EXPORT = qw( inf NaN );
126f3c5f JH	9
	10	use strict;
	11
	12	##############################################################################
	13
	14	# These are all alike, and thus faked by AUTOLOAD
	15
	16	my @faked = qw/round_mode accuracy precision div_scale/;
	17	use vars qw/$VERSION $AUTOLOAD $_lite/; # _lite for testsuite
	18
	19	sub AUTOLOAD
	20	{
	21	my $name = $AUTOLOAD;
	22
	23	$name =~ s/.*:://; # split package
	24	no strict 'refs';
	25	foreach my $n (@faked)
	26	{
	27	if ($n eq $name)
	28	{
	29	*{"bigrat::$name"} = sub
	30	{
	31	my $self = shift;
	32	no strict 'refs';
	33	if (defined $_[0])
	34	{
	35	Math::BigInt->$name($_[0]);
	36	Math::BigFloat->$name($_[0]);
990fb837	37	return Math::BigRat->$name($_[0]);
126f3c5f JH	38	}
	39	return Math::BigInt->$name();
	40	};
	41	return &$name;
	42	}
	43	}
	44
	45	# delayed load of Carp and avoid recursion
	46	require Carp;
	47	Carp::croak ("Can't call bigrat\-\>$name, not a valid method");
	48	}
	49
	50	sub upgrade
	51	{
	52	my $self = shift;
	53	no strict 'refs';
	54	# if (defined $_[0])
	55	# {
	56	# $Math::BigInt::upgrade = $_[0];
	57	# $Math::BigFloat::upgrade = $_[0];
	58	# }
	59	return $Math::BigInt::upgrade;
	60	}
	61
	62	sub import
	63	{
	64	my $self = shift;
	65
	66	# see also bignum->import() for additional comments
	67
	68	# some defaults
	69	my $lib = 'Calc'; my $upgrade = 'Math::BigFloat';
	70
	71	my @import = ( ':constant' ); # drive it w/ constant
	72	my @a = @_; my $l = scalar @_; my $j = 0;
	73	my ($a,$p);
	74	my ($ver,$trace); # version? trace?
	75	for ( my $i = 0; $i < $l ; $i++,$j++ )
	76	{
	77	if ($_[$i] eq 'upgrade')
	78	{
	79	# this causes upgrading
	80	$upgrade = $_[$i+1]; # or undef to disable
	81	my $s = 2; $s = 1 if @a-$j < 2; # avoid "can not modify non-existant..."
	82	splice @a, $j, $s; $j -= $s;
	83	}
	84	elsif ($_[$i] =~ /^(l\|lib)$/)
	85	{
	86	# this causes a different low lib to take care...
	87	$lib = $_[$i+1] \|\| '';
	88	my $s = 2; $s = 1 if @a-$j < 2; # avoid "can not modify non-existant..."
	89	splice @a, $j, $s; $j -= $s;
	90	}
	91	elsif ($_[$i] =~ /^(v\|version)$/)
	92	{
	93	$ver = 1;
	94	splice @a, $j, 1; $j --;
	95	}
	96	elsif ($_[$i] =~ /^(t\|trace)$/)
	97	{
	98	$trace = 1;
	99	splice @a, $j, 1; $j --;
	100	}
	101	else
102	{
103	die ("unknown option $_[$i]");
104	}
105	}
106	my $class;
107	$_lite = 0; # using M::BI::L ?
108	if ($trace)
109	{
110	require Math::BigInt::Trace; $class = 'Math::BigInt::Trace';
111	$upgrade = 'Math::BigFloat::Trace';
126f3c5f JH	112	}
	113	else
	114	{
	115	# see if we can find Math::BigInt::Lite
	116	if (!defined $a && !defined $p) # rounding won't work to well
	117	{
	118	eval 'require Math::BigInt::Lite;';
	119	if ($@ eq '')
	120	{
	121	@import = ( ); # :constant in Lite, not MBI
	122	Math::BigInt::Lite->import( ':constant' );
	123	$_lite= 1; # signal okay
	124	}
	125	}
	126	require Math::BigInt if $_lite == 0; # not already loaded?
	127	$class = 'Math::BigInt'; # regardless of MBIL or not
	128	}
	129	# Math::BigInt::Trace or plain Math::BigInt
	130	$class->import(@import, upgrade => $upgrade, lib => $lib);
	131
	132	require Math::BigFloat;
	133	Math::BigFloat->import( upgrade => 'Math::BigRat', ':constant' );
	134	require Math::BigRat;
	135	if ($ver)
	136	{
	137	print "bigrat\t\t\t v$VERSION\n";
	138	print "Math::BigInt::Lite\t v$Math::BigInt::Lite::VERSION\n" if $_lite;
	139	print "Math::BigInt\t\t v$Math::BigInt::VERSION";
	140	my $config = Math::BigInt->config();
	141	print " lib => $config->{lib} v$config->{lib_version}\n";
	142	print "Math::BigFloat\t\t v$Math::BigFloat::VERSION\n";
	143	print "Math::BigRat\t\t v$Math::BigRat::VERSION\n";
	144	exit;
	145	}
b4bc5691	146	$self->export_to_level(1,$self,@a); # export inf and NaN
126f3c5f JH	147	}
126f3c5f JH	148
b4bc5691 T	149	sub inf () { Math::BigInt->binf(); }
	150	sub NaN () { Math::BigInt->bnan(); }
	151
126f3c5f JH	152	1;
	153
	154	__END__
	155
	156	=head1 NAME
	157
b4bc5691	158	bigrat - Transparent BigNumber/BigRationale support for Perl
126f3c5f JH	159
	160	=head1 SYNOPSIS
	161
	162	use bigrat;
	163
	164	$x = 2 + 4.5,"\n"; # BigFloat 6.5
	165	print 1/3 + 1/4,"\n"; # produces 7/12
	166
	167	=head1 DESCRIPTION
	168
	169	All operators (inlcuding basic math operations) are overloaded. Integer and
	170	floating-point constants are created as proper BigInts or BigFloats,
	171	respectively.
	172
	173	Other than L<bignum>, this module upgrades to Math::BigRat, meaning that
	174	instead of 2.5 you will get 2+1/2 as output.
	175
	176	=head2 MODULES USED
	177
	178	C<bigrat> is just a thin wrapper around various modules of the Math::BigInt
	179	family. Think of it as the head of the family, who runs the shop, and orders
	180	the others to do the work.
	181
	182	The following modules are currently used by bignum:
	183
	184	Math::BigInt::Lite (for speed, and only if it is loadable)
	185	Math::BigInt
	186	Math::BigFloat
	187	Math::BigRat
	188
	189	=head2 MATH LIBRARY
	190
	191	Math with the numbers is done (by default) by a module called
	192	Math::BigInt::Calc. This is equivalent to saying:
	193
	194	use bigrat lib => 'Calc';
	195
	196	You can change this by using:
	197
	198	use bigrat lib => 'BitVect';
	199
	200	The following would first try to find Math::BigInt::Foo, then
	201	Math::BigInt::Bar, and when this also fails, revert to Math::BigInt::Calc:
	202
	203	use bigrat lib => 'Foo,Math::BigInt::Bar';
	204
	205	Please see respective module documentation for further details.
	206
	207	=head2 SIGN
	208
	209	The sign is either '+', '-', 'NaN', '+inf' or '-inf' and stored seperately.
	210
	211	A sign of 'NaN' is used to represent the result when input arguments are not
	212	numbers or as a result of 0/0. '+inf' and '-inf' represent plus respectively
	213	minus infinity. You will get '+inf' when dividing a positive number by 0, and
	214	'-inf' when dividing any negative number by 0.
	215
	216	=head2 METHODS
	217
	218	Since all numbers are not objects, you can use all functions that are part of
	219	the BigInt or BigFloat API. It is wise to use only the bxxx() notation, and not
	220	the fxxx() notation, though. This makes you independed on the fact that the
	221	underlying object might morph into a different class than BigFloat.
	222
990fb837 RGS	223	=head2 CAVEAT
	224
	225	But a warning is in order. When using the following to make a copy of a number,
	226	only a shallow copy will be made.
	227
	228	$x = 9; $y = $x;
	229	$x = $y = 7;
	230
	231	Using the copy or the original with overloaded math is okay, e.g. the
	232	following work:
	233
	234	$x = 9; $y = $x;
	235	print $x + 1, " ", $y,"\n"; # prints 10 9
	236
	237	but calling any method that modifies the number directly will result in
	238	B<both> the original and the copy beeing destroyed:
	239
	240	$x = 9; $y = $x;
	241	print $x->badd(1), " ", $y,"\n"; # prints 10 10
	242
	243	$x = 9; $y = $x;
	244	print $x->binc(1), " ", $y,"\n"; # prints 10 10
	245
	246	$x = 9; $y = $x;
	247	print $x->bmul(2), " ", $y,"\n"; # prints 18 18
	248
	249	Using methods that do not modify, but testthe contents works:
	250
	251	$x = 9; $y = $x;
	252	$z = 9 if $x->is_zero(); # works fine
	253
	254	See the documentation about the copy constructor and C<=> in overload, as
	255	well as the documentation in BigInt for further details.
	256
126f3c5f JH	257	=head1 EXAMPLES
	258
	259	perl -Mbigrat -le 'print sqrt(33)'
	260	perl -Mbigrat -le 'print 2*255'
	261	perl -Mbigrat -le 'print 4.5+2*255'
	262	perl -Mbigrat -le 'print 3/7 + 5/7 + 8/3'
	263	perl -Mbigrat -le 'print 12->is_odd()';
	264
	265	=head1 LICENSE
	266
	267	This program is free software; you may redistribute it and/or modify it under
	268	the same terms as Perl itself.
	269
	270	=head1 SEE ALSO
	271
	272	Especially L<bignum>.
	273
	274	L<Math::BigFloat>, L<Math::BigInt>, L<Math::BigRat> and L<Math::Big> as well
	275	as L<Math::BigInt::BitVect>, L<Math::BigInt::Pari> and L<Math::BigInt::GMP>.
	276
	277	=head1 AUTHORS
	278
	279	(C) by Tels L<http://bloodgate.com/> in early 2002.
	280
	281	=cut