使用Parse::RecDescent收集数据

Question

我有一个字符串列表（30000+），它们是语句的集合。从逻辑上讲，Parse::RecDescent是用来解析字符串以收集数据的工具，但我就是无法理解语法规范的构造。

下面的代码正在构建一个受祝福的节点的大列表，但是我不知道如何真正创建一个更有用的数据结构（我只想要Year、Vol和Iss值）

#!/usr/bin/perl
use strict;
use warnings;
use Parse::RecDescent;
use Data::Dumper;
my $string1 = '2006 - v. 1 (1-2), 2007 - v. 2 (1-4), 2008 - v. 3 (1-4), 2009 - v. 4 (1-4), 2010 - v. 5 (1-4), 2011 - v. 6 (1-2), 2012 - v. 7 (1, 4), 2013/2014 - v. 8 (1-4), 2014 - v. 9 (1, 3)';
my $string2 = 'v.35(1,2),v.36(1,2),v.33(1,2),v.34(1,2),v.39(1,2),v.37(1,2),v.38(1,2),v.43(1,2),v.42(1,2),v.41(1,2),v.40(1,2),v.22(),v.23(),v.24(),v.25(1),v.26(),v.27(),v.28(1,2),v.29(1,2),v.3(),v.2(1,2),v.1(1,2),v.30(),v.7(),v.6(),v.32(1,2),v.5(),v.4(),v.31()';
my $string3 = '1820/1825 - v. 1 (1-2), 1821/1825 - v. 2 (3-4), 1821/1826 - v. 3 (5-6), 1821 - v. 4 (7-8), 1822 - v. 5 (9-10), 1823 - v. 6 (11-12), 1823 - v. 7 (13-14), 1823 - v. 8 (15-16), 1824 - v. 9 (17-18)';
my $data = {}; # Edit: Added hash-ref to show alternate testing
my $grammar = q {
   <autotree> 
     Holdings  : Node(s /,/) 
     Node      : When(?) Volume Issue { $data->{ $item{when} } = [ $item{Vol}, $item{Iss} ] } # Edit: Action Added - This was one option I tried
     When      : Years | Year { $arg[0] = $item{When} } 
     Years     : Year '/' Year
     Year      : /\d{4}/  { $item[1] } # Edit: Action Added - This was another option I tried
     Volume    : /v\.\s*/ Vol { $arg[1] = $item{Vol} } # Edit: Add commet "This was blindly flailing to work out how to get variable data
     Vol       : /\d+/
     Issue     : /\s*(/ Iss ')' { $arg[2] = $item{Iss} }
     Iss       : /[\d+\-\,]*/ 
     };
my $parser = Parse::RecDescent->new($grammar);
foreach my $string ( ($string1, $string2, $string3) ) {
  $string =~ s/s+-s+//g;
  print "$stringn";
  my $output = $parser->Holdings($string);
  print Dumper $output;
}

顺便说一句，我该如何写语法语句，这样我就不需要循环中的替换了？

Answer 1

make_parser.pl:

#!/usr/bin/perl
use strict;
use warnings;
use Parse::RecDescent qw( );
my $grammar = <<'__END_OF_GRAMMAR__';
   {
      use strict;
      use warnings;
   }
   parse    : Holdings /Z/            { $item[1] }
   Holdings : Node(s /,/)             #{ $item[-1] }
   Node     : When /-?/ Node_          { [ $item[1], @{$item[3]} ] }
            | Node_                    { [ undef,    @{$item[1]} ] }
   Node_    : Volume Issue             { [ $item[1], $item[2] ] }
   When     : Year When_[ $item[1] ]  #{ $item[-1] }
   When_    : '/' Year                 { $arg[0] . '/' . $item[2] }
            |                          { $arg[0] }
   Year     : /d{4}/                 #{ $item[-1] }
   Volume   : /v.s*/ /d+/          #{ $item[-1] }
   Issue    : '(' /[^)]*/ ')'          { $item[2] =~ s/s//gr }
__END_OF_GRAMMAR__
Parse::RecDescent->Precompile($grammar, 'Grammar')
   or die("Bad grammarn");

a.pl:

#!/usr/bin/perl
use strict;
use warnings;
use Grammar qw( );
#$::RD_TRACE = 1;
my $parser = Grammar->new();
while (<DATA>) {
   chomp;
   my $recs = $parser->parse($_)
      or do { warn("Bad data at line $.n");
              next;
            };
   print("For: $_n");
   for my $rec (@$recs) {
      printf("   %s | %s | %sn",
         defined($rec->[0]) ? $rec->[0] : '[undef]',
         $rec->[1],
         $rec->[2],
      );
   }
}
__DATA__
2006 - v. 1 (1-2), 2007 - v. 2 (1-4), 2008 - v. 3 (1-4), 2009 - v. 4 (1-4), 2010 - v. 5 (1-4), 2011 - v. 6 (1-2), 2012 - v. 7 (1, 4), 2013/2014 - v. 8 (1-4), 2014 - v. 9 (1, 3)
v.35(1,2),v.36(1,2),v.33(1,2),v.34(1,2),v.39(1,2),v.37(1,2),v.38(1,2),v.43(1,2),v.42(1,2),v.41(1,2),v.40(1,2),v.22(),v.23(),v.24(),v.25(1),v.26(),v.27(),v.28(1,2),v.29(1,2),v.3(),v.2(1,2),v.1(1,2),v.30(),v.7(),v.6(),v.32(1,2),v.5(),v.4(),v.31()
1820/1825 - v. 1 (1-2), 1821/1825 - v. 2 (3-4), 1821/1826 - v. 3 (5-6), 1821 - v. 4 (7-8), 1822 - v. 5 (9-10), 1823 - v. 6 (11-12), 1823 - v. 7 (13-14), 1823 - v. 8 (15-16), 1824 - v. 9 (17-18)

输出：

$ perl make_parser.pl
$ perl a.pl
For: 2006 - v. 1 (1-2), 2007 - v. 2 (1-4), 2008 - v. 3 (1-4), 2009 - v. 4 (1-4), 2010 - v. 5 (1-4), 2011 - v. 6 (1-2), 2012 - v. 7 (1, 4), 2013/2014 - v. 8 (1-4), 2014 - v. 9 (1, 3)
   2006 | 1 | 1-2
   2007 | 2 | 1-4
   2008 | 3 | 1-4
   2009 | 4 | 1-4
   2010 | 5 | 1-4
   2011 | 6 | 1-2
   2012 | 7 | 1,4
   2013/2014 | 8 | 1-4
   2014 | 9 | 1,3
For: v.35(1,2),v.36(1,2),v.33(1,2),v.34(1,2),v.39(1,2),v.37(1,2),v.38(1,2),v.43(1,2),v.42(1,2),v.41(1,2),v.40(1,2),v.22(),v.23(),v.24(),v.25(1),v.26(),v.27(),v.28(1,2),v.29(1,2),v.3(),v.2(1,2),v.1(1,2),v.30(),v.7(),v.6(),v.32(1,2),v.5(),v.4(),v.31()
   [undef] | 35 | 1,2
   [undef] | 36 | 1,2
   [undef] | 33 | 1,2
   [undef] | 34 | 1,2
   [undef] | 39 | 1,2
   [undef] | 37 | 1,2
   [undef] | 38 | 1,2
   [undef] | 43 | 1,2
   [undef] | 42 | 1,2
   [undef] | 41 | 1,2
   [undef] | 40 | 1,2
   [undef] | 22 |
   [undef] | 23 |
   [undef] | 24 |
   [undef] | 25 | 1
   [undef] | 26 |
   [undef] | 27 |
   [undef] | 28 | 1,2
   [undef] | 29 | 1,2
   [undef] | 3 |
   [undef] | 2 | 1,2
   [undef] | 1 | 1,2
   [undef] | 30 |
   [undef] | 7 |
   [undef] | 6 |
   [undef] | 32 | 1,2
   [undef] | 5 |
   [undef] | 4 |
   [undef] | 31 |
For: 1820/1825 - v. 1 (1-2), 1821/1825 - v. 2 (3-4), 1821/1826 - v. 3 (5-6), 1821 - v. 4 (7-8), 1822 - v. 5 (9-10), 1823 - v. 6 (11-12), 1823 - v. 7 (13-14), 1823 - v. 8 (15-16), 1824 - v. 9 (17-18)
   1820/1825 | 1 | 1-2
   1821/1825 | 2 | 3-4
   1821/1826 | 3 | 5-6
   1821 | 4 | 7-8
   1822 | 5 | 9-10
   1823 | 6 | 11-12
   1823 | 7 | 13-14
   1823 | 8 | 15-16
   1824 | 9 | 17-18