[perl5.git] / lib / bigrat.pm

package bigrat;
require 5.005;

$VERSION = '0.07';
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 = '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; $i++;
      }
    elsif ($_[$i] =~ /^(a|accuracy)$/)
      {
      $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
    }
  # 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;

  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 (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'.

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 Cavaet

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 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.

=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
b68b7ab1 T	4	$VERSION = '0.07';
b68b7ab1 T	5	require Exporter;
b4bc5691 T	6	@ISA = qw( Exporter );
	7	@EXPORT_OK = qw( );
	8	@EXPORT = qw( inf NaN );
126f3c5f JH	9
	10	use strict;
	11
	12	##############################################################################
	13
	14	# These are all alike, and thus faked by AUTOLOAD
	15
	16	my @faked = qw/round_mode accuracy precision div_scale/;
	17	use vars qw/$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
	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..."
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	}
	141	# Math::BigInt::Trace or plain Math::BigInt
	142	$class->import(@import, upgrade => $upgrade, lib => $lib);
	143
	144	require Math::BigFloat;
	145	Math::BigFloat->import( upgrade => 'Math::BigRat', ':constant' );
	146	require Math::BigRat;
b68b7ab1 T	147
	148	bigrat->accuracy($a) if defined $a;
	149	bigrat->precision($p) if defined $p;
126f3c5f JH	150	if ($ver)
	151	{
	152	print "bigrat\t\t\t v$VERSION\n";
	153	print "Math::BigInt::Lite\t v$Math::BigInt::Lite::VERSION\n" if $_lite;
	154	print "Math::BigInt\t\t v$Math::BigInt::VERSION";
	155	my $config = Math::BigInt->config();
	156	print " lib => $config->{lib} v$config->{lib_version}\n";
	157	print "Math::BigFloat\t\t v$Math::BigFloat::VERSION\n";
	158	print "Math::BigRat\t\t v$Math::BigRat::VERSION\n";
	159	exit;
	160	}
b4bc5691	161	$self->export_to_level(1,$self,@a); # export inf and NaN
126f3c5f JH	162	}
126f3c5f JH	163
b4bc5691 T	164	sub inf () { Math::BigInt->binf(); }
	165	sub NaN () { Math::BigInt->bnan(); }
	166
126f3c5f JH	167	1;
	168
	169	__END__
	170
	171	=head1 NAME
	172
b1f79218	173	bigrat - Transparent BigNumber/BigRational support for Perl
126f3c5f JH	174
	175	=head1 SYNOPSIS
	176
	177	use bigrat;
	178
	179	$x = 2 + 4.5,"\n"; # BigFloat 6.5
	180	print 1/3 + 1/4,"\n"; # produces 7/12
	181
	182	=head1 DESCRIPTION
	183
	184	All operators (inlcuding basic math operations) are overloaded. Integer and
	185	floating-point constants are created as proper BigInts or BigFloats,
	186	respectively.
	187
	188	Other than L<bignum>, this module upgrades to Math::BigRat, meaning that
	189	instead of 2.5 you will get 2+1/2 as output.
	190
b68b7ab1	191	=head2 Modules Used
126f3c5f JH	192
	193	C<bigrat> is just a thin wrapper around various modules of the Math::BigInt
	194	family. Think of it as the head of the family, who runs the shop, and orders
	195	the others to do the work.
	196
	197	The following modules are currently used by bignum:
	198
	199	Math::BigInt::Lite (for speed, and only if it is loadable)
	200	Math::BigInt
	201	Math::BigFloat
	202	Math::BigRat
	203
b68b7ab1	204	=head2 Math Library
126f3c5f JH	205
	206	Math with the numbers is done (by default) by a module called
	207	Math::BigInt::Calc. This is equivalent to saying:
	208
	209	use bigrat lib => 'Calc';
	210
	211	You can change this by using:
	212
	213	use bigrat lib => 'BitVect';
	214
	215	The following would first try to find Math::BigInt::Foo, then
	216	Math::BigInt::Bar, and when this also fails, revert to Math::BigInt::Calc:
	217
	218	use bigrat lib => 'Foo,Math::BigInt::Bar';
	219
	220	Please see respective module documentation for further details.
	221
b68b7ab1	222	=head2 Sign
126f3c5f	223
b68b7ab1	224	The sign is either '+', '-', 'NaN', '+inf' or '-inf'.
126f3c5f JH	225
	226	A sign of 'NaN' is used to represent the result when input arguments are not
	227	numbers or as a result of 0/0. '+inf' and '-inf' represent plus respectively
	228	minus infinity. You will get '+inf' when dividing a positive number by 0, and
	229	'-inf' when dividing any negative number by 0.
	230
b68b7ab1	231	=head2 Methods
126f3c5f JH	232
	233	Since all numbers are not objects, you can use all functions that are part of
	234	the BigInt or BigFloat API. It is wise to use only the bxxx() notation, and not
	235	the fxxx() notation, though. This makes you independed on the fact that the
	236	underlying object might morph into a different class than BigFloat.
	237
b68b7ab1	238	=head2 Cavaet
990fb837 RGS	239
	240	But a warning is in order. When using the following to make a copy of a number,
	241	only a shallow copy will be made.
	242
	243	$x = 9; $y = $x;
	244	$x = $y = 7;
	245
b68b7ab1 T	246	If you want to make a real copy, use the following:
	247
	248	$y = $x->copy();
	249
990fb837 RGS	250	Using the copy or the original with overloaded math is okay, e.g. the
	251	following work:
	252
	253	$x = 9; $y = $x;
	254	print $x + 1, " ", $y,"\n"; # prints 10 9
	255
	256	but calling any method that modifies the number directly will result in
	257	B<both> the original and the copy beeing destroyed:
	258
	259	$x = 9; $y = $x;
	260	print $x->badd(1), " ", $y,"\n"; # prints 10 10
	261
	262	$x = 9; $y = $x;
	263	print $x->binc(1), " ", $y,"\n"; # prints 10 10
	264
	265	$x = 9; $y = $x;
	266	print $x->bmul(2), " ", $y,"\n"; # prints 18 18
	267
	268	Using methods that do not modify, but testthe contents works:
	269
	270	$x = 9; $y = $x;
	271	$z = 9 if $x->is_zero(); # works fine
	272
	273	See the documentation about the copy constructor and C<=> in overload, as
	274	well as the documentation in BigInt for further details.
	275
b68b7ab1 T	276	=head2 Options
	277
	278	bignum recognizes some options that can be passed while loading it via use.
	279	The options can (currently) be either a single letter form, or the long form.
	280	The following options exist:
	281
	282	=over 2
	283
	284	=item a or accuracy
	285
	286	This sets the accuracy for all math operations. The argument must be greater
	287	than or equal to zero. See Math::BigInt's bround() function for details.
	288
	289	perl -Mbigrat=a,50 -le 'print sqrt(20)'
	290
	291	=item p or precision
	292
	293	This sets the precision for all math operations. The argument can be any
	294	integer. Negative values mean a fixed number of digits after the dot, while
	295	a positive value rounds to this digit left from the dot. 0 or 1 mean round to
	296	integer. See Math::BigInt's bfround() function for details.
	297
	298	perl -Mbigrat=p,-50 -le 'print sqrt(20)'
	299
	300	=item t or trace
	301
	302	This enables a trace mode and is primarily for debugging bignum or
	303	Math::BigInt/Math::BigFloat.
	304
	305	=item l or lib
	306
	307	Load a different math lib, see L<MATH LIBRARY>.
	308
	309	perl -Mbigrat=l,GMP -e 'print 2 ** 512'
	310
	311	Currently there is no way to specify more than one library on the command
	312	line. This will be hopefully fixed soon ;)
	313
	314	=item v or version
	315
	316	This prints out the name and version of all modules used and then exits.
	317
	318	perl -Mbigrat=v
	319
126f3c5f JH	320	=head1 EXAMPLES
	321
	322	perl -Mbigrat -le 'print sqrt(33)'
	323	perl -Mbigrat -le 'print 2*255'
	324	perl -Mbigrat -le 'print 4.5+2*255'
	325	perl -Mbigrat -le 'print 3/7 + 5/7 + 8/3'
	326	perl -Mbigrat -le 'print 12->is_odd()';
	327
	328	=head1 LICENSE
	329
	330	This program is free software; you may redistribute it and/or modify it under
	331	the same terms as Perl itself.
	332
	333	=head1 SEE ALSO
	334
	335	Especially L<bignum>.
	336
	337	L<Math::BigFloat>, L<Math::BigInt>, L<Math::BigRat> and L<Math::Big> as well
	338	as L<Math::BigInt::BitVect>, L<Math::BigInt::Pari> and L<Math::BigInt::GMP>.
	339
	340	=head1 AUTHORS
	341
b68b7ab1	342	(C) by Tels L<http://bloodgate.com/> in early 2002 - 2005.
126f3c5f JH	343
126f3c5f JH	344	=cut