perl/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 (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
Revision:	1.1
Committed:	Thu Jun 30 14:27:08 2005 UTC (21 years, 3 months ago) by root
Branch:	MAIN
CVS Tags:	PERL-5-8-7, HEAD
Branch point for:	PERL
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	package bigrat;
2			require 5.005;
3
4			$VERSION = '0.08';
5			require Exporter;
6			@ISA = qw( Exporter );
7			@EXPORT_OK = qw( );
8			@EXPORT = qw( inf NaN );
9
10			use strict;
11
12			##############################################################################
13
14			# These are all alike, and thus faked by AUTOLOAD
15
16			my @faked = qw/round_mode accuracy precision div_scale/;
17			use vars qw/$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($_[0]);
37			return Math::BigRat->$name($_[0]);
38			}
39			return Math::BigInt->$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 = ''; 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; $i++;
90			}
91			elsif ($_[$i] =~ /^(a\|accuracy)$/)
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; $i++;
102			}
103			elsif ($_[$i] =~ /^(v\|version)$/)
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';
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			push @import, 'lib' => $lib if $lib ne '';
142			# Math::BigInt::Trace or plain Math::BigInt
143			$class->import(@import, upgrade => $upgrade);
144
145			require Math::BigFloat;
146			Math::BigFloat->import( upgrade => 'Math::BigRat', ':constant' );
147			require Math::BigRat;
148
149			bigrat->accuracy($a) if defined $a;
150			bigrat->precision($p) if defined $p;
151			if ($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			}
162			$self->export_to_level(1,$self,@a); # export inf and NaN
163			}
164
165			sub inf () { Math::BigInt->binf(); }
166			sub NaN () { Math::BigInt->bnan(); }
167
168			1;
169
170			__END__
171
172			=head1 NAME
173
174			bigrat - Transparent BigNumber/BigRational support for Perl
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
185			All operators (inlcuding basic math operations) are overloaded. Integer and
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
192			=head2 Modules Used
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
205			=head2 Math Library
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
223			=head2 Sign
224
225			The sign is either '+', '-', 'NaN', '+inf' or '-inf'.
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
232			=head2 Methods
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
239			=head2 Cavaet
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
247			If you want to make a real copy, use the following:
248
249			$y = $x->copy();
250
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
258			B<both> the original and the copy beeing destroyed:
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
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
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
343			(C) by Tels L<http://bloodgate.com/> in early 2002 - 2005.
344
345			=cut