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1 | package bigint; |
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2 | use 5.006002; |
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3 | |
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4 | $VERSION = '0.22'; |
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5 | use Exporter; |
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6 | @ISA = qw( Exporter ); |
7 | @EXPORT_OK = qw( ); |
8 | @EXPORT = qw( inf NaN ); |
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9 | |
10 | use strict; |
11 | use overload; |
12 | |
13 | ############################################################################## |
14 | |
15 | # These are all alike, and thus faked by AUTOLOAD |
16 | |
17 | my @faked = qw/round_mode accuracy precision div_scale/; |
18 | use vars qw/$VERSION $AUTOLOAD $_lite/; # _lite for testsuite |
19 | |
20 | sub AUTOLOAD |
21 | { |
22 | my $name = $AUTOLOAD; |
23 | |
24 | $name =~ s/.*:://; # split package |
25 | no strict 'refs'; |
26 | foreach my $n (@faked) |
27 | { |
28 | if ($n eq $name) |
29 | { |
30 | *{"bigint::$name"} = sub |
31 | { |
32 | my $self = shift; |
33 | no strict 'refs'; |
34 | if (defined $_[0]) |
35 | { |
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36 | return Math::BigInt->$name($_[0]); |
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37 | } |
38 | return Math::BigInt->$name(); |
39 | }; |
40 | return &$name; |
41 | } |
42 | } |
43 | |
44 | # delayed load of Carp and avoid recursion |
45 | require Carp; |
46 | Carp::croak ("Can't call bigint\-\>$name, not a valid method"); |
47 | } |
48 | |
49 | sub upgrade |
50 | { |
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51 | $Math::BigInt::upgrade; |
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52 | } |
53 | |
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54 | sub _binary_constant |
55 | { |
56 | # this takes a binary/hexadecimal/octal constant string and returns it |
57 | # as string suitable for new. Basically it converts octal to decimal, and |
58 | # passes every thing else unmodified back. |
59 | my $string = shift; |
60 | |
61 | return Math::BigInt->new($string) if $string =~ /^0[bx]/; |
62 | |
63 | # so it must be an octal constant |
64 | Math::BigInt->from_oct($string); |
65 | } |
66 | |
67 | sub _float_constant |
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68 | { |
69 | # this takes a floating point constant string and returns it truncated to |
70 | # integer. For instance, '4.5' => '4', '1.234e2' => '123' etc |
71 | my $float = shift; |
72 | |
73 | # some simple cases first |
74 | return $float if ($float =~ /^[+-]?[0-9]+$/); # '+123','-1','0' etc |
75 | return $float |
76 | if ($float =~ /^[+-]?[0-9]+\.?[eE]\+?[0-9]+$/); # 123e2, 123.e+2 |
77 | return '0' if ($float =~ /^[+-]?[0]*\.[0-9]+$/); # .2, 0.2, -.1 |
78 | if ($float =~ /^[+-]?[0-9]+\.[0-9]*$/) # 1., 1.23, -1.2 etc |
79 | { |
80 | $float =~ s/\..*//; |
81 | return $float; |
82 | } |
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83 | my ($mis,$miv,$mfv,$es,$ev) = Math::BigInt::_split($float); |
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84 | return $float if !defined $mis; # doesn't look like a number to me |
85 | my $ec = int($$ev); |
86 | my $sign = $$mis; $sign = '' if $sign eq '+'; |
87 | if ($$es eq '-') |
88 | { |
89 | # ignore fraction part entirely |
90 | if ($ec >= length($$miv)) # 123.23E-4 |
91 | { |
92 | return '0'; |
93 | } |
94 | return $sign . substr ($$miv,0,length($$miv)-$ec); # 1234.45E-2 = 12 |
95 | } |
96 | # xE+y |
97 | if ($ec >= length($$mfv)) |
98 | { |
99 | $ec -= length($$mfv); |
100 | return $sign.$$miv.$$mfv if $ec == 0; # 123.45E+2 => 12345 |
101 | return $sign.$$miv.$$mfv.'E'.$ec; # 123.45e+3 => 12345e1 |
102 | } |
103 | $mfv = substr($$mfv,0,$ec); |
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104 | $sign.$$miv.$mfv; # 123.45e+1 => 1234 |
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105 | } |
106 | |
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107 | sub unimport |
108 | { |
109 | $^H{bigint} = undef; # no longer in effect |
110 | overload::remove_constant('binary','','float','','integer'); |
111 | } |
112 | |
113 | sub in_effect |
114 | { |
115 | my $level = shift || 0; |
116 | my $hinthash = (caller($level))[10]; |
117 | $hinthash->{bigint}; |
118 | } |
119 | |
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120 | sub import |
121 | { |
122 | my $self = shift; |
123 | |
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124 | $^H{bigint} = 1; # we are in effect |
125 | |
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126 | # some defaults |
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127 | my $lib = ''; my $lib_kind = 'try'; |
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128 | |
129 | my @import = ( ':constant' ); # drive it w/ constant |
130 | my @a = @_; my $l = scalar @_; my $j = 0; |
131 | my ($ver,$trace); # version? trace? |
132 | my ($a,$p); # accuracy, precision |
133 | for ( my $i = 0; $i < $l ; $i++,$j++ ) |
134 | { |
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135 | if ($_[$i] =~ /^(l|lib|try|only)$/) |
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136 | { |
137 | # this causes a different low lib to take care... |
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138 | $lib_kind = $1; $lib_kind = 'lib' if $lib_kind eq 'l'; |
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139 | $lib = $_[$i+1] || ''; |
140 | my $s = 2; $s = 1 if @a-$j < 2; # avoid "can not modify non-existant..." |
141 | splice @a, $j, $s; $j -= $s; $i++; |
142 | } |
143 | elsif ($_[$i] =~ /^(a|accuracy)$/) |
144 | { |
145 | $a = $_[$i+1]; |
146 | my $s = 2; $s = 1 if @a-$j < 2; # avoid "can not modify non-existant..." |
147 | splice @a, $j, $s; $j -= $s; $i++; |
148 | } |
149 | elsif ($_[$i] =~ /^(p|precision)$/) |
150 | { |
151 | $p = $_[$i+1]; |
152 | my $s = 2; $s = 1 if @a-$j < 2; # avoid "can not modify non-existant..." |
153 | splice @a, $j, $s; $j -= $s; $i++; |
154 | } |
155 | elsif ($_[$i] =~ /^(v|version)$/) |
156 | { |
157 | $ver = 1; |
158 | splice @a, $j, 1; $j --; |
159 | } |
160 | elsif ($_[$i] =~ /^(t|trace)$/) |
161 | { |
162 | $trace = 1; |
163 | splice @a, $j, 1; $j --; |
164 | } |
165 | else { die "unknown option $_[$i]"; } |
166 | } |
167 | my $class; |
168 | $_lite = 0; # using M::BI::L ? |
169 | if ($trace) |
170 | { |
171 | require Math::BigInt::Trace; $class = 'Math::BigInt::Trace'; |
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172 | } |
173 | else |
174 | { |
175 | # see if we can find Math::BigInt::Lite |
176 | if (!defined $a && !defined $p) # rounding won't work to well |
177 | { |
178 | eval 'require Math::BigInt::Lite;'; |
179 | if ($@ eq '') |
180 | { |
181 | @import = ( ); # :constant in Lite, not MBI |
182 | Math::BigInt::Lite->import( ':constant' ); |
183 | $_lite= 1; # signal okay |
184 | } |
185 | } |
186 | require Math::BigInt if $_lite == 0; # not already loaded? |
187 | $class = 'Math::BigInt'; # regardless of MBIL or not |
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188 | } |
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189 | push @import, $lib_kind => $lib if $lib ne ''; |
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190 | # Math::BigInt::Trace or plain Math::BigInt |
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191 | $class->import(@import); |
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192 | |
193 | bigint->accuracy($a) if defined $a; |
194 | bigint->precision($p) if defined $p; |
195 | if ($ver) |
196 | { |
197 | print "bigint\t\t\t v$VERSION\n"; |
198 | print "Math::BigInt::Lite\t v$Math::BigInt::Lite::VERSION\n" if $_lite; |
199 | print "Math::BigInt\t\t v$Math::BigInt::VERSION"; |
200 | my $config = Math::BigInt->config(); |
201 | print " lib => $config->{lib} v$config->{lib_version}\n"; |
202 | exit; |
203 | } |
204 | # we take care of floating point constants, since BigFloat isn't available |
205 | # and BigInt doesn't like them: |
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206 | overload::constant float => sub { Math::BigInt->new( _float_constant(shift) ); }; |
207 | # Take care of octal/hexadecimal constants |
208 | overload::constant binary => sub { _binary_constant(shift) }; |
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209 | |
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210 | # if another big* was already loaded: |
211 | my ($package) = caller(); |
212 | |
213 | no strict 'refs'; |
214 | if (!defined *{"${package}::inf"}) |
215 | { |
216 | $self->export_to_level(1,$self,@a); # export inf and NaN |
217 | } |
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218 | } |
219 | |
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220 | sub inf () { Math::BigInt->binf(); } |
221 | sub NaN () { Math::BigInt->bnan(); } |
222 | |
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223 | 1; |
224 | |
225 | __END__ |
226 | |
227 | =head1 NAME |
228 | |
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229 | bigint - Transparent BigInteger support for Perl |
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230 | |
231 | =head1 SYNOPSIS |
232 | |
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233 | use bigint; |
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234 | |
235 | $x = 2 + 4.5,"\n"; # BigInt 6 |
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236 | print 2 ** 512,"\n"; # really is what you think it is |
237 | print inf + 42,"\n"; # inf |
238 | print NaN * 7,"\n"; # NaN |
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239 | |
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240 | { |
241 | no bigint; |
242 | print 2 ** 256,"\n"; # a normal Perl scalar now |
243 | } |
244 | |
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245 | =head1 DESCRIPTION |
246 | |
247 | All operators (including basic math operations) are overloaded. Integer |
248 | constants are created as proper BigInts. |
249 | |
250 | Floating point constants are truncated to integer. All results are also |
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251 | truncated. |
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252 | |
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253 | =head2 Options |
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254 | |
255 | bigint recognizes some options that can be passed while loading it via use. |
256 | The options can (currently) be either a single letter form, or the long form. |
257 | The following options exist: |
258 | |
259 | =over 2 |
260 | |
261 | =item a or accuracy |
262 | |
263 | This sets the accuracy for all math operations. The argument must be greater |
264 | than or equal to zero. See Math::BigInt's bround() function for details. |
265 | |
266 | perl -Mbigint=a,2 -le 'print 12345+1' |
267 | |
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268 | Note that setting precision and accurary at the same time is not possible. |
269 | |
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270 | =item p or precision |
271 | |
272 | This sets the precision for all math operations. The argument can be any |
273 | integer. Negative values mean a fixed number of digits after the dot, and |
274 | are <B>ignored</B> since all operations happen in integer space. |
275 | A positive value rounds to this digit left from the dot. 0 or 1 mean round to |
276 | integer and are ignore like negative values. |
277 | |
278 | See Math::BigInt's bfround() function for details. |
279 | |
280 | perl -Mbignum=p,5 -le 'print 123456789+123' |
281 | |
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282 | Note that setting precision and accurary at the same time is not possible. |
283 | |
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284 | =item t or trace |
285 | |
286 | This enables a trace mode and is primarily for debugging bigint or |
287 | Math::BigInt. |
288 | |
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289 | =item l, lib, try or only |
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290 | |
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291 | Load a different math lib, see L<Math Library>. |
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292 | |
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293 | perl -Mbigint=lib,GMP -e 'print 2 ** 512' |
294 | perl -Mbigint=try,GMP -e 'print 2 ** 512' |
295 | perl -Mbigint=only,GMP -e 'print 2 ** 512' |
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296 | |
297 | Currently there is no way to specify more than one library on the command |
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298 | line. This means the following does not work: |
299 | |
300 | perl -Mbignum=l,GMP,Pari -e 'print 2 ** 512' |
301 | |
302 | This will be hopefully fixed soon ;) |
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303 | |
304 | =item v or version |
305 | |
306 | This prints out the name and version of all modules used and then exits. |
307 | |
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308 | perl -Mbigint=v |
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309 | |
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310 | =back |
311 | |
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312 | =head2 Math Library |
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313 | |
314 | Math with the numbers is done (by default) by a module called |
315 | Math::BigInt::Calc. This is equivalent to saying: |
316 | |
317 | use bigint lib => 'Calc'; |
318 | |
319 | You can change this by using: |
320 | |
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321 | use bignum lib => 'GMP'; |
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322 | |
323 | The following would first try to find Math::BigInt::Foo, then |
324 | Math::BigInt::Bar, and when this also fails, revert to Math::BigInt::Calc: |
325 | |
326 | use bigint lib => 'Foo,Math::BigInt::Bar'; |
327 | |
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328 | Using C<lib> warns if none of the specified libraries can be found and |
329 | L<Math::BigInt> did fall back to one of the default libraries. |
330 | To supress this warning, use C<try> instead: |
331 | |
332 | use bignum try => 'GMP'; |
333 | |
334 | If you want the code to die instead of falling back, use C<only> instead: |
335 | |
336 | use bignum only => 'GMP'; |
337 | |
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338 | Please see respective module documentation for further details. |
339 | |
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340 | =head2 Internal Format |
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341 | |
342 | The numbers are stored as objects, and their internals might change at anytime, |
343 | especially between math operations. The objects also might belong to different |
344 | classes, like Math::BigInt, or Math::BigInt::Lite. Mixing them together, even |
345 | with normal scalars is not extraordinary, but normal and expected. |
346 | |
347 | You should not depend on the internal format, all accesses must go through |
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348 | accessor methods. E.g. looking at $x->{sign} is not a good idea since there |
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349 | is no guaranty that the object in question has such a hash key, nor is a hash |
350 | underneath at all. |
351 | |
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352 | =head2 Sign |
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353 | |
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354 | The sign is either '+', '-', 'NaN', '+inf' or '-inf'. |
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355 | You can access it with the sign() method. |
356 | |
357 | A sign of 'NaN' is used to represent the result when input arguments are not |
358 | numbers or as a result of 0/0. '+inf' and '-inf' represent plus respectively |
359 | minus infinity. You will get '+inf' when dividing a positive number by 0, and |
360 | '-inf' when dividing any negative number by 0. |
361 | |
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362 | =head2 Methods |
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363 | |
364 | Since all numbers are now objects, you can use all functions that are part of |
365 | the BigInt API. You can only use the bxxx() notation, and not the fxxx() |
366 | notation, though. |
367 | |
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368 | =over 2 |
369 | |
370 | =item inf() |
371 | |
372 | A shortcut to return Math::BigInt->binf(). Useful because Perl does not always |
373 | handle bareword C<inf> properly. |
374 | |
375 | =item NaN() |
376 | |
377 | A shortcut to return Math::BigInt->bnan(). Useful because Perl does not always |
378 | handle bareword C<NaN> properly. |
379 | |
380 | =item upgrade() |
381 | |
382 | Return the class that numbers are upgraded to, is in fact returning |
383 | C<$Math::BigInt::upgrade>. |
384 | |
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385 | =item in_effect() |
386 | |
387 | use bigint; |
388 | |
389 | print "in effect\n" if bigint::in_effect; # true |
390 | { |
391 | no bigint; |
392 | print "in effect\n" if bigint::in_effect; # false |
393 | } |
394 | |
395 | Returns true or false if C<bigint> is in effect in the current scope. |
396 | |
397 | This method only works on Perl v5.9.4 or later. |
398 | |
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399 | =back |
400 | |
401 | =head2 MATH LIBRARY |
402 | |
403 | Math with the numbers is done (by default) by a module called |
404 | |
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405 | =head2 Caveat |
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406 | |
407 | But a warning is in order. When using the following to make a copy of a number, |
408 | only a shallow copy will be made. |
409 | |
410 | $x = 9; $y = $x; |
411 | $x = $y = 7; |
412 | |
413 | Using the copy or the original with overloaded math is okay, e.g. the |
414 | following work: |
415 | |
416 | $x = 9; $y = $x; |
417 | print $x + 1, " ", $y,"\n"; # prints 10 9 |
418 | |
419 | but calling any method that modifies the number directly will result in |
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420 | B<both> the original and the copy being destroyed: |
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421 | |
422 | $x = 9; $y = $x; |
423 | print $x->badd(1), " ", $y,"\n"; # prints 10 10 |
424 | |
425 | $x = 9; $y = $x; |
426 | print $x->binc(1), " ", $y,"\n"; # prints 10 10 |
427 | |
428 | $x = 9; $y = $x; |
429 | print $x->bmul(2), " ", $y,"\n"; # prints 18 18 |
430 | |
431 | Using methods that do not modify, but testthe contents works: |
432 | |
433 | $x = 9; $y = $x; |
434 | $z = 9 if $x->is_zero(); # works fine |
435 | |
436 | See the documentation about the copy constructor and C<=> in overload, as |
437 | well as the documentation in BigInt for further details. |
438 | |
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439 | =head1 MODULES USED |
440 | |
441 | C<bigint> is just a thin wrapper around various modules of the Math::BigInt |
442 | family. Think of it as the head of the family, who runs the shop, and orders |
443 | the others to do the work. |
444 | |
445 | The following modules are currently used by bigint: |
446 | |
447 | Math::BigInt::Lite (for speed, and only if it is loadable) |
448 | Math::BigInt |
449 | |
450 | =head1 EXAMPLES |
451 | |
452 | Some cool command line examples to impress the Python crowd ;) You might want |
453 | to compare them to the results under -Mbignum or -Mbigrat: |
454 | |
455 | perl -Mbigint -le 'print sqrt(33)' |
456 | perl -Mbigint -le 'print 2*255' |
457 | perl -Mbigint -le 'print 4.5+2*255' |
458 | perl -Mbigint -le 'print 3/7 + 5/7 + 8/3' |
459 | perl -Mbigint -le 'print 123->is_odd()' |
460 | perl -Mbigint -le 'print log(2)' |
461 | perl -Mbigint -le 'print 2 ** 0.5' |
462 | perl -Mbigint=a,65 -le 'print 2 ** 0.2' |
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463 | perl -Mbignum=a,65,l,GMP -le 'print 7 ** 7777' |
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464 | |
465 | =head1 LICENSE |
466 | |
467 | This program is free software; you may redistribute it and/or modify it under |
468 | the same terms as Perl itself. |
469 | |
470 | =head1 SEE ALSO |
471 | |
472 | Especially L<bigrat> as in C<perl -Mbigrat -le 'print 1/3+1/4'> and |
473 | L<bignum> as in C<perl -Mbignum -le 'print sqrt(2)'>. |
474 | |
475 | L<Math::BigInt>, L<Math::BigRat> and L<Math::Big> as well |
476 | as L<Math::BigInt::BitVect>, L<Math::BigInt::Pari> and L<Math::BigInt::GMP>. |
477 | |
478 | =head1 AUTHORS |
479 | |
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480 | (C) by Tels L<http://bloodgate.com/> in early 2002 - 2007. |
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481 | |
482 | =cut |