1package Text::WordDiff; 2 3use strict; 4use vars qw(@ISA $VERSION); 5use Algorithm::Diff (); 6use IO::File; 7use Carp; 8 9$VERSION = '0.08'; 10 11# _Mastering Regular Expressions_, p. 132. 12my $BEGIN_WORD = $] >= 5.006 13 ? qr/(?:(?<!\p{IsWord})(?=\p{IsWord})|(?<!\p{IsPunct})(?=\p{IsPunct})|(?<!\p{IsCntrl})(?=\p{IsCntrl}))/msx 14 : qr/(?:(?<!\w)(?=\w)|(?<![\]\[!"%&'()*,\.\/:;?\{}\-@])(?=[\]\[!"%&'()*,\.\/:;?\{}\-@])|(?<![\n\r\t])(?=[\n\r\t]))/msx; 15 16my %styles = ( 17 ANSIColor => undef, 18 HTML => undef, 19 HTMLTwoLines => undef, 20); 21 22sub import { 23 my $caller = caller; 24 no strict 'refs'; 25 *{"$caller\::word_diff"} = \&word_diff; 26} 27 28sub word_diff ($$;$) { 29 my @seqs = ( shift, shift ); 30 my $opts = $_[0] ? { %{ +shift } } : {}; 31 $opts->{FILENAME_PREFIX_A} ||= '---'; 32 $opts->{FILENAME_PREFIX_B} ||= '+++'; 33 my $AorB = 'A'; 34 35 for my $seq (@seqs) { 36 my $type = ref $seq; 37 38 while ( $type eq 'CODE' ) { 39 $seq = $seq->( $opts ); 40 $type = ref $seq; 41 } 42 43 # Get a handle on options. 44 my $filename = \$opts->{"FILENAME_$AorB"}; 45 my $mtime = \$opts->{"MTIME_$AorB"}; 46 47 if ( $type eq 'ARRAY' ) { 48 # The work has already been done for us. 49 } 50 51 elsif ( $type eq 'SCALAR' ) { 52 # Parse the words from the string. 53 $seq = [ split $BEGIN_WORD, $$seq ]; 54 } 55 56 elsif ( !$type ) { 57 # Assume that it's a raw file name. 58 $$filename = $seq unless defined $$filename; 59 $$mtime = (stat $seq)[9] unless defined $$mtime; 60 61 # Parse the words from the file. 62 my $seq_fh = IO::File->new($seq, '<'); 63 $seq = do { local $/; [ split $BEGIN_WORD, <$seq_fh> ] }; 64 $seq_fh->close; 65 } 66 67 elsif ( $type eq "GLOB" || UNIVERSAL::isa( $seq, "IO::Handle" ) ) { 68 # Parse the words from the file. 69 $seq = do { local $/; [ split $BEGIN_WORD, <$seq> ] }; 70 } 71 72 else { 73 # Damn. 74 confess "Can't handle input of type $type"; 75 } 76 $AorB++; 77 } 78 79 # Set up the output handler. 80 my $output; 81 my $out_handler = delete $opts->{OUTPUT}; 82 my $type = ref $out_handler ; 83 84 if ( ! defined $out_handler ) { 85 # Default to concatenating a string. 86 $output = ''; 87 $out_handler = sub { $output .= shift }; 88 } 89 elsif ( $type eq 'CODE' ) { 90 # We'll just use the handler. 91 } 92 elsif ( $type eq 'SCALAR' ) { 93 # Append to the scalar reference. 94 my $out_ref = $out_handler; 95 $out_handler = sub { $$out_ref .= shift }; 96 } 97 elsif ( $type eq 'ARRAY' ) { 98 # Push each item onto the array. 99 my $out_ref = $out_handler; 100 $out_handler = sub { push @$out_ref, shift }; 101 } 102 elsif ( $type eq 'GLOB' || UNIVERSAL::isa( $out_handler, 'IO::Handle' )) { 103 # print to the file handle. 104 my $output_handle = $out_handler; 105 $out_handler = sub { print $output_handle shift }; 106 } 107 else { 108 # D'oh! 109 croak "Unrecognized output type: $type"; 110 } 111 112 # Instantiate the diff object, along with any options. 113 my $diff = Algorithm::Diff->new(@seqs, delete $opts->{DIFF_OPTS}); 114 115 # Load the style class and instantiate an instance. 116 my $style = delete $opts->{STYLE} || 'ANSIColor'; 117 $style = __PACKAGE__ . "::$style" if exists $styles{$style}; 118 eval "require $style" or die $@ unless $style->can('new'); 119 $style = $style->new($opts) if !ref $style; 120 121 # Run the diff. 122 my $hunks = 0; 123 $out_handler->($style->file_header()); 124 while ($diff->Next) { 125 $hunks++; 126 $out_handler->( $style->hunk_header() ); 127 128 # Output unchanged items. 129 if (my @same = $diff->Same) { 130 $out_handler->( $style->same_items(@same) ); 131 } 132 133 # Output deleted and inserted items. 134 else { 135 if (my @del = $diff->Items(1)) { 136 $out_handler->( $style->delete_items(@del) ); 137 } 138 if (my @ins = $diff->Items(2)) { 139 $out_handler->( $style->insert_items(@ins) ); 140 } 141 } 142 $out_handler->( $style->hunk_footer() ); 143 } 144 $out_handler->( $style->file_footer() ); 145 146 return defined $output ? $output : $hunks; 147} 148 149package Text::WordDiff::Base; 150 151sub new { 152 my ($class, $opts) = @_; 153 return bless { %{$opts} } => $class; 154} 155 156 157sub file_header { 158 my $self = shift; 159 my $fn1 = $self->filename_a; 160 my $fn2 = $self->filename_b; 161 return '' unless defined $fn1 && defined $fn2; 162 163 my $p1 = $self->filename_prefix_a; 164 my $t1 = $self->mtime_a; 165 my $p2 = $self->filename_prefix_b; 166 my $t2 = $self->mtime_b; 167 168 return "$p1 $fn1" . (defined $t1 ? "\t" . localtime $t1 : '') . "\n" 169 . "$p2 $fn2" . (defined $t2 ? "\t" . localtime $t2 : '') . "\n" 170 ; 171} 172 173sub hunk_header { return '' } 174sub same_items { return '' } 175sub insert_items { return '' } 176sub delete_items { return '' } 177sub hunk_footer { return '' } 178sub file_footer { return '' } 179sub filename_a { return shift->{FILENAME_A} } 180sub filename_b { return shift->{FILENAME_B} } 181sub mtime_a { return shift->{MTIME_A} } 182sub mtime_b { return shift->{MTIME_B} } 183sub filename_prefix_a { return shift->{FILENAME_PREFIX_A} } 184sub filename_prefix_b { return shift->{FILENAME_PREFIX_B} } 185 1861; 187__END__ 188 189############################################################################## 190 191=head1 Name 192 193Text::WordDiff - Track changes between documents 194 195=head1 Synopsis 196 197 use Text::WordDiff; 198 199 my $diff = word_diff 'file1.txt', 'file2.txt', { STYLE => 'HTML' }; 200 my $diff = word_diff \$string1, \$string2, { STYLE => 'ANSIColor' }; 201 my $diff = word_diff \*FH1, \*FH2; \%options; 202 my $diff = word_diff \&reader1, \&reader2; 203 my $diff = word_diff \@records1, \@records2; 204 205 # May also mix input types: 206 my $diff = word_diff \@records1, 'file_B.txt'; 207 208=head1 Description 209 210This module is a variation on the lovely L<Text::Diff|Text::Diff> module. 211Rather than generating traditional line-oriented diffs, however, it generates 212word-oriented diffs. This can be useful for tracking changes in narrative 213documents or documents with very long lines. To diff source code, one is still 214best off using L<Text::Diff|Text::Diff>. But if you want to see how a short 215story changed from one version to the next, this module will do the job very 216nicely. 217 218=head2 What is a Word? 219 220I'm glad you asked! Well, sort of. It's a really hard question to answer. I 221consulted a number of sources, but really just did my best to punt on the 222question by reformulating it as, "How do I split text up into individual 223words?" The short answer is to split on word boundaries. However, every word 224has two boundaries, one at the beginning and one at the end. So splitting on 225C</\b/> didn't work so well. What I really wanted to do was to split on the 226I<beginning> of every word. Fortunately, _Mastering Regular Expressions_ has a 227recipe for that: C<< /(?<!\w)(?=\w)/ >>. I've borrowed this regular expression 228for use in Perls before 5.6.x, but go for the Unicode variant in 5.6.0 and 229newer: C<< /(?<!\p{IsWord})(?=\p{IsWord})/ >>. Adding some additional controls 230for punctuation and control characters, this sentence, for example, would be 231split up into the following tokens: 232 233 my @words = ( 234 "Adding ", 235 "some ", 236 "additional ", 237 "controls", 238 "\n", 239 "for ", 240 "punctuation ", 241 "and ", 242 "control ", 243 "characters", 244 ", ", 245 "this ", 246 "sentence", 247 ", ", 248 "for ", 249 "example", 250 ", ", 251 "would ", 252 "be", 253 "\n", 254 "split ", 255 "up ", 256 "into ", 257 "the ", 258 "following ", 259 "tokens", 260 ":", 261 ); 262 263So it's not just comparing words, but word-like tokens and control/punctuation 264tokens. This makes sense to me, at least, as the diff is between these tokens, 265and thus leads to a nice word-and-space-and-punctuation type diff. It's not 266unlike what a word processor might do (although a lot of them are 267character-based, but that seemed a bit extreme--feel free to dupe this module 268into Text::CharDiff!). 269 270Now, I acknowledge that there are localization issues with this approach. In 271particular, it will fail with Chinese, Japanese, and Korean text, as these 272languages don't put non-word characters between words. Ideally, Test::WordDiff 273would then split on every charaters (since a single character often equals a 274word), but such is not the case when the C<utf8> flag is set on a string. 275For example, This simple script: 276 277=encoding utf8 278 279 use strict; 280 use utf8; 281 use Data::Dumper; 282 my $string = '뼈뼉뼘뼙뼛뼜뼝뽀뽁뽄뽈뽐뽑뽕뾔뾰뿅뿌뿍뿐뿔뿜뿟뿡쀼쁑쁘쁜쁠쁨쁩삐'; 283 my @tokens = split /(?<!\p{IsWord})(?=\p{IsWord})/msx, $string; 284 print Dumper \@tokens; 285 286Outputs: 287 288 $VAR1 = [ 289 "\x{bf08}\x{bf09}\x{bf18}\x{bf19}\x{bf1b}\x{bf1c}\x{bf1d}\x{bf40}\x{bf41}\x{bf44}\x{bf48}\x{bf50}\x{bf51}\x{bf55}\x{bf94}\x{bfb0}\x{bfc5}\x{bfcc}\x{bfcd}\x{bfd0}\x{bfd4}\x{bfdc}\x{bfdf}\x{bfe1}\x{c03c}\x{c051}\x{c058}\x{c05c}\x{c060}\x{c068}\x{c069}\x{c090}" 290 ]; 291 292Not so useful. It seems to be less of a problem if the C<use utf8;> line is 293commented out, in which case we get: 294 295 $VAR1 = [ 296 '뼈', 297 '뼉', 298 '뼘', 299 '뼙', 300 '뼛', 301 '뼜', 302 '뼝', 303 '뽀', 304 '뽁', 305 '뽄', 306 '뽈', 307 '뽐', 308 '뽑', 309 '뽕', 310 '뾔', 311 '뾰', 312 '뿅', 313 '뿌', 314 '뿍', 315 '뿐', 316 '뿔', 317 '뿜', 318 '뿟', 319 '뿡', 320 '?', 321 '?쁑', 322 '쁘', 323 '쁜', 324 '쁠', 325 '쁨', 326 '쁩', 327 '삐' 328 ]; 329 330Someone whose more familiar with non-space-using languages will have to 331explain to me how I might be able to duplicate this pattern within the scope 332of C<use utf8;>, seing as it may very well be important to have it on in order 333to ensure proper character semantics. 334 335However, if my word tokenization approach is just too naive, and you decide 336that you need to take a different approach (maybe use 337L<Lingua::ZH::Toke|Lingua::ZH::Toke> or similar module), you can still use 338this module; you'll just have to tokenize your strings into words yourself, 339and pass them to word_diff() as array references: 340 341 word_diff \@my_words1, \@my_words2; 342 343=head1 Options 344 345word_diff() takes two arguments from which to draw input and an optional hash 346reference of options to control its output. The first two arguments contain 347the data to be diffed, and each may be in the form of any of the following 348(that is, they can be in two different formats): 349 350=over 351 352=item * String 353 354A bare scalar will be assumed to be a file name. The file will be opened and 355split up into words. word_diff() will also C<stat> the file to get the last 356modified time for use in the header, unless the relevant option (C<MTIME_A> or 357C<MTIME_B>) has been specified explicitly. 358 359=item * Scalar Reference 360 361A scalar reference will be assumed to refer to a string. That string will be 362split up into words. 363 364=item * Array Reference 365 366An array reference will be assumed to be a list of words. 367 368=item * File Handle 369 370A glob or IO::Handle-derived object will be read from and split up into 371its constituent words. 372 373=back 374 375The optional hash reference may contain the following options. Additional 376options may be specified by the formattting class; see the specific class for 377details. 378 379=over 380 381=item * STYLE 382 383"ANSIColor", "HTML" or an object or class name for a class providing 384C<file_header()>, C<hunk_header()>, C<same_items()>, C<delete_items()>, 385C<insert_items()>, C<hunk_footer()> and C<file_footer()> methods. Defaults to 386"ANSIColor" for nice display of diffs in an ANSI Color-supporting terminal. 387 388If the package indicated by the C<STYLE> has no C<new()> method, 389C<word_diff()> will load it automatically (lazy loading). It will then 390instantiate an object of that class, passing in the options hash reference 391with which the formatting class can initialize the object. 392 393Styles may be specified as class names (C<< STYLE => "My::Foo" >>), in which 394case they will be instantiated by calling the C<new()> construcctor and 395passing in the options hash reference, or as objects (C<< STYLE => 396My::Foo->new >>). 397 398The simplest way to implement your own formatting style is to create a new 399class that inherits from Text::WordDiff::Base, wherein the C<new()> method is 400already provided, and the C<file_header()> returns a Unified diff-style 401header. All of the other formatting methods simply return empty strings, and 402are therefore ripe for overriding. 403 404=item * FILENAME_A, MTIME_A, FILENAME_B, MTIME_B 405 406The name of the file and the modification time "files" in epoch seconds. 407Unless a defined value is specified for these options, they will be filled in 408for each file when word_diff() is passed a filename. If a filename is not 409passed in and C<FILENAME_A> and C<FILENAME_B> are not defined, the header will 410not be printed by the base formatting base class. 411 412=item * OUTPUT 413 414The method by which diff output should be, well, I<output>. Examples and their 415equivalent subroutines: 416 417 OUTPUT => \*FOOHANDLE, # like: sub { print FOOHANDLE shift() } 418 OUTPUT => \$output, # like: sub { $output .= shift } 419 OUTPUT => \@output, # like: sub { push @output, shift } 420 OUTPUT => sub { $output .= shift }, 421 422If C<OUTPUT> is not defined, word_diff() will simply return the diff as a 423string. If C<OUTPUT> is a code reference, it will be called once with the file 424header, once for each hunk body, and once for each piece of content. If 425C<OUTPUT> is an L<IO::Handle|IO::Handle>-derived object, output will be 426sent to that handle. 427 428=item * FILENAME_PREFIX_A, FILENAME_PREFIX_B 429 430The string to print before the filename in the header. Defaults are C<"---">, 431C<"+++">. 432 433=item * DIFF_OPTS 434 435A hash reference to be passed as the options to C<< Algorithm::Diff->new >>. 436See L<Algorithm::Diff|Algorithm::Diff> for details on available options. 437 438=back 439 440=head1 Formatting Classes 441 442Text::WordDiff comes with two formatting classes: 443 444=over 445 446=item L<Text::WordDiff::ANSIColor|Text::WordDiff::ANSIColor> 447 448This is the default formatting class. It emits a header and then the diff 449content, with deleted text in bodfaced red and inserted text in boldfaced 450green. 451 452=item L<Text::WordDiff::HTML|Text::WordDiff::HTML> 453 454Specify C<< STYLE => 'HTML' >> to take advantage of this formatting class. It 455outputs the diff content as XHTML, with deleted text in C<< <del> >> elements 456and inserted text in C<< <ins> >> elements. 457 458=back 459 460To implement your own formatting class, simply inherit from 461Text::WordDiff::Base and override its methods as necssary. By default, 462only the C<file_header()> formatting method returns a value. All others 463simply return empty strings, and are therefore ripe for overriding: 464 465 package My::WordDiff::Format; 466 use base 'Text::WordDiff::Base'; 467 468 sub file_footer { return "End of diff\n"; } 469 470The methods supplied by the base class are: 471 472=over 473 474=item C<new()> 475 476Constructs and returns a new formatting object. It takes a single hash 477reference as its argument, and uses it to construct the object. The nice thing 478about this is that if you want to support other options in your formatting 479class, you can just use them in the formatting object constructed by the 480Text::WordDiff::Base class and document that they can be passed as 481part of the options hash refernce to word_diff(). 482 483=item C<file_header()> 484 485Called once for a single call to C<word_diff()>, this method outputs the 486header for the whole diff. This is the only formatting method in the base 487class that returns anything other than an empty string. It collects the 488filenames from C<filname_a()> and C<filename_b()> and, if they're defined, 489uses the relevant prefixes and modification times to return a unified 490diff-style header. 491 492=item C<hunk_header()> 493 494This method is called for each diff hunk. It should output any necessary 495header for the hunk. 496 497=item C<same_items()> 498 499This method is called for items that have not changed between the two 500sequnces being compared. The unchanged items will be passed as a 501list to the method. 502 503=item C<delete_items> 504 505This method is called for items in the first sequence that are not present in 506the second sequcne. The deleted items will be passed as a list to the method. 507 508=item C<insert_items> 509 510This method is called for items in the second sequence that are not present in 511the first sequcne. The inserted items will be passed as a list to the method. 512 513=item C<hunk_footer> 514 515This method is called at the end of a hunk. It should output any necessary 516content to close out the hunk. 517 518=item C<file_footer()> 519 520This method is called once when the whole diff has been procssed. It should 521output any necessary content to close out the diff file. 522 523=item C<filename_a> 524 525This accessor returns the value specified for the C<FILENAME_A> option 526to word_diff(). 527 528=item C<filename_b> 529 530This accessor returns the value specified for the C<FILENAME_B> option 531to word_diff(). 532 533=item C<mtime_a> 534 535This accessor returns the value specified for the C<MTIME_A> option to 536word_diff(). 537 538=item C<mtime_b> 539 540This accessor returns the value specified for the C<MTIME_B> option to 541word_diff(). 542 543=item C<filename_prefix_a> 544 545This accessor returns the value specified for the C<FILENAME_PREFIX_A> option 546to word_diff(). 547 548=item C<filename_prefix_b> 549 550This accessor returns the value specified for the C<FILENAME_PREFIX_B> option 551to word_diff(). 552 553=back 554 555=head1 See Also 556 557=over 558 559=item L<Text::Diff|Text::Diff> 560 561Inspired the interface and implementation of this module. Thanks Barry! 562 563=item L<Text::ParagraphDiff|Text::ParagraphDiff> 564 565A module that attempts to diff paragraphs and the words in them. 566 567=item L<Algorithm::Diff|Algorithm::Diff> 568 569The module that makes this all possible. 570 571=back 572 573=head1 Support 574 575This module is stored in an open L<GitHub 576repository|http://github.com/theory/text-worddiff/>. Feel free to fork and 577contribute! 578 579Please file bug reports via L<GitHub 580Issues|http://github.com/theory/text-worddiff/issues/> or by sending mail to 581L<bug-Text-WordDiff@rt.cpan.org|mailto:bug-Text-WordDiff@rt.cpan.org>. 582 583=head1 Author 584 585David E. Wheeler <david@justatheory.com> 586 587=head1 Copyright and License 588 589Copyright (c) 2005-2011 David E. Wheeler. Some Rights Reserved. 590 591This module is free software; you can redistribute it and/or modify it under 592the same terms as Perl itself. 593 594=cut 595