[perl5.git] / lib / bigrat.pm

package bigrat;
require 5.005;

$VERSION = '0.08';
require 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 = ''; 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; $i++;
      }
    elsif ($_[$i] =~ /^(a|accuracy)$/)
      {
      $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 --;
      }
    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
    }
  push @import, 'lib' => $lib if $lib ne '';
  # Math::BigInt::Trace or plain Math::BigInt
  $class->import(@import, upgrade => $upgrade);

  require Math::BigFloat;
  Math::BigFloat->import( upgrade => 'Math::BigRat', ':constant' );
  require Math::BigRat;

  bigrat->accuracy($a) if defined $a;
  bigrat->precision($p) if defined $p;
  if ($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/BigRational 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 (including 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'.

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;

If you want to make a real copy, use the following:

	$y = $x->copy();

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 being 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.

=head2 Options

bignum recognizes some options that can be passed while loading it via use.
The options can (currently) be either a single letter form, or the long form.
The following options exist:

=over 2

=item a or accuracy

This sets the accuracy for all math operations. The argument must be greater
than or equal to zero. See Math::BigInt's bround() function for details.

	perl -Mbigrat=a,50 -le 'print sqrt(20)'

=item p or precision

This sets the precision for all math operations. The argument can be any
integer. Negative values mean a fixed number of digits after the dot, while
a positive value rounds to this digit left from the dot. 0 or 1 mean round to
integer. See Math::BigInt's bfround() function for details.

	perl -Mbigrat=p,-50 -le 'print sqrt(20)'

=item t or trace

This enables a trace mode and is primarily for debugging bignum or
Math::BigInt/Math::BigFloat.

=item l or lib

Load a different math lib, see L<MATH LIBRARY>.

	perl -Mbigrat=l,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 ;)

=item v or version

This prints out the name and version of all modules used and then exits.

	perl -Mbigrat=v

=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 - 2005.

=cut
Commit	Line	Data
126f3c5f JH	1	package bigrat;
	2	require 5.005;
	3
233f7bc0	4	$VERSION = '0.08';
b68b7ab1	5	require Exporter;
b4bc5691 T	6	@ISA = qw( Exporter );
	7	@EXPORT_OK = qw( );
	8	@EXPORT = qw( inf NaN );
126f3c5f JH	9
	10	use strict;
	11
	12	##############################################################################
	13
	14	# These are all alike, and thus faked by AUTOLOAD
	15
	16	my @faked = qw/round_mode accuracy precision div_scale/;
	17	use vars qw/$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
233f7bc0	69	my $lib = ''; my $upgrade = 'Math::BigFloat';
126f3c5f JH	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..."
b68b7ab1 T	89	splice @a, $j, $s; $j -= $s; $i++;
	90	}
	91	elsif ($_[$i] =~ /^(a\|accuracy)$/)
	92	{
	93	$a = $_[$i+1];
	94	my $s = 2; $s = 1 if @a-$j < 2; # avoid "can not modify non-existant..."
	95	splice @a, $j, $s; $j -= $s; $i++;
	96	}
	97	elsif ($_[$i] =~ /^(p\|precision)$/)
	98	{
	99	$p = $_[$i+1];
	100	my $s = 2; $s = 1 if @a-$j < 2; # avoid "can not modify non-existant..."
	101	splice @a, $j, $s; $j -= $s; $i++;
126f3c5f JH	102	}
	103	elsif ($_[$i] =~ /^(v\|version)$/)
	104	{
	105	$ver = 1;
	106	splice @a, $j, 1; $j --;
	107	}
	108	elsif ($_[$i] =~ /^(t\|trace)$/)
	109	{
	110	$trace = 1;
	111	splice @a, $j, 1; $j --;
	112	}
	113	else
	114	{
	115	die ("unknown option $_[$i]");
	116	}
	117	}
	118	my $class;
	119	$_lite = 0; # using M::BI::L ?
	120	if ($trace)
	121	{
	122	require Math::BigInt::Trace; $class = 'Math::BigInt::Trace';
	123	$upgrade = 'Math::BigFloat::Trace';
126f3c5f JH	124	}
	125	else
	126	{
	127	# see if we can find Math::BigInt::Lite
	128	if (!defined $a && !defined $p) # rounding won't work to well
	129	{
	130	eval 'require Math::BigInt::Lite;';
	131	if ($@ eq '')
	132	{
	133	@import = ( ); # :constant in Lite, not MBI
	134	Math::BigInt::Lite->import( ':constant' );
	135	$_lite= 1; # signal okay
	136	}
	137	}
	138	require Math::BigInt if $_lite == 0; # not already loaded?
	139	$class = 'Math::BigInt'; # regardless of MBIL or not
	140	}
233f7bc0	141	push @import, 'lib' => $lib if $lib ne '';
126f3c5f	142	# Math::BigInt::Trace or plain Math::BigInt
233f7bc0	143	$class->import(@import, upgrade => $upgrade);
126f3c5f JH	144
	145	require Math::BigFloat;
	146	Math::BigFloat->import( upgrade => 'Math::BigRat', ':constant' );
	147	require Math::BigRat;
b68b7ab1 T	148
	149	bigrat->accuracy($a) if defined $a;
	150	bigrat->precision($p) if defined $p;
126f3c5f JH	151	if ($ver)
	152	{
	153	print "bigrat\t\t\t v$VERSION\n";
	154	print "Math::BigInt::Lite\t v$Math::BigInt::Lite::VERSION\n" if $_lite;
	155	print "Math::BigInt\t\t v$Math::BigInt::VERSION";
	156	my $config = Math::BigInt->config();
	157	print " lib => $config->{lib} v$config->{lib_version}\n";
	158	print "Math::BigFloat\t\t v$Math::BigFloat::VERSION\n";
	159	print "Math::BigRat\t\t v$Math::BigRat::VERSION\n";
	160	exit;
	161	}
b4bc5691	162	$self->export_to_level(1,$self,@a); # export inf and NaN
126f3c5f JH	163	}
126f3c5f JH	164
b4bc5691 T	165	sub inf () { Math::BigInt->binf(); }
	166	sub NaN () { Math::BigInt->bnan(); }
	167
126f3c5f JH	168	1;
	169
	170	__END__
	171
	172	=head1 NAME
	173
b1f79218	174	bigrat - Transparent BigNumber/BigRational support for Perl
126f3c5f JH	175
	176	=head1 SYNOPSIS
	177
	178	use bigrat;
	179
	180	$x = 2 + 4.5,"\n"; # BigFloat 6.5
	181	print 1/3 + 1/4,"\n"; # produces 7/12
	182
	183	=head1 DESCRIPTION
	184
3c4b39be	185	All operators (including basic math operations) are overloaded. Integer and
126f3c5f JH	186	floating-point constants are created as proper BigInts or BigFloats,
	187	respectively.
	188
	189	Other than L<bignum>, this module upgrades to Math::BigRat, meaning that
	190	instead of 2.5 you will get 2+1/2 as output.
	191
b68b7ab1	192	=head2 Modules Used
126f3c5f JH	193
	194	C<bigrat> is just a thin wrapper around various modules of the Math::BigInt
	195	family. Think of it as the head of the family, who runs the shop, and orders
	196	the others to do the work.
	197
	198	The following modules are currently used by bignum:
	199
	200	Math::BigInt::Lite (for speed, and only if it is loadable)
	201	Math::BigInt
	202	Math::BigFloat
	203	Math::BigRat
	204
b68b7ab1	205	=head2 Math Library
126f3c5f JH	206
	207	Math with the numbers is done (by default) by a module called
	208	Math::BigInt::Calc. This is equivalent to saying:
	209
	210	use bigrat lib => 'Calc';
	211
	212	You can change this by using:
	213
	214	use bigrat lib => 'BitVect';
	215
	216	The following would first try to find Math::BigInt::Foo, then
	217	Math::BigInt::Bar, and when this also fails, revert to Math::BigInt::Calc:
	218
	219	use bigrat lib => 'Foo,Math::BigInt::Bar';
	220
	221	Please see respective module documentation for further details.
	222
b68b7ab1	223	=head2 Sign
126f3c5f	224
b68b7ab1	225	The sign is either '+', '-', 'NaN', '+inf' or '-inf'.
126f3c5f JH	226
	227	A sign of 'NaN' is used to represent the result when input arguments are not
	228	numbers or as a result of 0/0. '+inf' and '-inf' represent plus respectively
	229	minus infinity. You will get '+inf' when dividing a positive number by 0, and
	230	'-inf' when dividing any negative number by 0.
	231
b68b7ab1	232	=head2 Methods
126f3c5f JH	233
	234	Since all numbers are not objects, you can use all functions that are part of
	235	the BigInt or BigFloat API. It is wise to use only the bxxx() notation, and not
	236	the fxxx() notation, though. This makes you independed on the fact that the
	237	underlying object might morph into a different class than BigFloat.
	238
3c4b39be	239	=head2 Caveat
990fb837 RGS	240
	241	But a warning is in order. When using the following to make a copy of a number,
	242	only a shallow copy will be made.
	243
	244	$x = 9; $y = $x;
	245	$x = $y = 7;
	246
b68b7ab1 T	247	If you want to make a real copy, use the following:
	248
	249	$y = $x->copy();
	250
990fb837 RGS	251	Using the copy or the original with overloaded math is okay, e.g. the
	252	following work:
	253
	254	$x = 9; $y = $x;
	255	print $x + 1, " ", $y,"\n"; # prints 10 9
	256
	257	but calling any method that modifies the number directly will result in
3c4b39be	258	B<both> the original and the copy being destroyed:
990fb837 RGS	259
	260	$x = 9; $y = $x;
	261	print $x->badd(1), " ", $y,"\n"; # prints 10 10
	262
	263	$x = 9; $y = $x;
	264	print $x->binc(1), " ", $y,"\n"; # prints 10 10
	265
	266	$x = 9; $y = $x;
	267	print $x->bmul(2), " ", $y,"\n"; # prints 18 18
	268
	269	Using methods that do not modify, but testthe contents works:
	270
	271	$x = 9; $y = $x;
	272	$z = 9 if $x->is_zero(); # works fine
	273
	274	See the documentation about the copy constructor and C<=> in overload, as
	275	well as the documentation in BigInt for further details.
	276
b68b7ab1 T	277	=head2 Options
	278
	279	bignum recognizes some options that can be passed while loading it via use.
	280	The options can (currently) be either a single letter form, or the long form.
	281	The following options exist:
	282
	283	=over 2
	284
	285	=item a or accuracy
	286
	287	This sets the accuracy for all math operations. The argument must be greater
	288	than or equal to zero. See Math::BigInt's bround() function for details.
	289
	290	perl -Mbigrat=a,50 -le 'print sqrt(20)'
	291
	292	=item p or precision
	293
	294	This sets the precision for all math operations. The argument can be any
	295	integer. Negative values mean a fixed number of digits after the dot, while
	296	a positive value rounds to this digit left from the dot. 0 or 1 mean round to
	297	integer. See Math::BigInt's bfround() function for details.
	298
	299	perl -Mbigrat=p,-50 -le 'print sqrt(20)'
	300
	301	=item t or trace
	302
	303	This enables a trace mode and is primarily for debugging bignum or
	304	Math::BigInt/Math::BigFloat.
	305
	306	=item l or lib
	307
	308	Load a different math lib, see L<MATH LIBRARY>.
	309
	310	perl -Mbigrat=l,GMP -e 'print 2 ** 512'
	311
	312	Currently there is no way to specify more than one library on the command
	313	line. This will be hopefully fixed soon ;)
	314
	315	=item v or version
	316
	317	This prints out the name and version of all modules used and then exits.
	318
	319	perl -Mbigrat=v
	320
126f3c5f JH	321	=head1 EXAMPLES
	322
	323	perl -Mbigrat -le 'print sqrt(33)'
	324	perl -Mbigrat -le 'print 2*255'
	325	perl -Mbigrat -le 'print 4.5+2*255'
	326	perl -Mbigrat -le 'print 3/7 + 5/7 + 8/3'
	327	perl -Mbigrat -le 'print 12->is_odd()';
	328
	329	=head1 LICENSE
	330
	331	This program is free software; you may redistribute it and/or modify it under
	332	the same terms as Perl itself.
	333
	334	=head1 SEE ALSO
	335
	336	Especially L<bignum>.
	337
	338	L<Math::BigFloat>, L<Math::BigInt>, L<Math::BigRat> and L<Math::Big> as well
	339	as L<Math::BigInt::BitVect>, L<Math::BigInt::Pari> and L<Math::BigInt::GMP>.
	340
	341	=head1 AUTHORS
	342
b68b7ab1	343	(C) by Tels L<http://bloodgate.com/> in early 2002 - 2005.
126f3c5f JH	344
126f3c5f JH	345	=cut