正则表达式 – Perl替换嵌套块正则表达式

这是针对@daliaessam的,是对@Miller轶事的递归解析的具体回应
使用正则表达式.

只有3个部分需要考虑.所以,使用我之前的表现形式,我向你们展示了一个
关于如何做到这一点的模板.它并不像你想象的那么难.

干杯!

# //////////////////////////////////////////////////////
 # // The General Guide to 3-Part Recursive Parsing
 # // ----------------------------------------------
 # // Part 1. CONTENT
 # // Part 2. CORE
 # // Part 3. ERRORS

 (?is)

 (?:
      (                                  # (1),Take off CONTENT
           (?&content) 
      )
   |                                   # OR
      (?>                                # Start-Delimiter (in this case,must be atomic because of .*?)
           <!--block:
           ( .*? )                            # (2),Block name
           -->
      )
      (                                  # (3),Take off The CORE
           (?&core) 
        |  
      )
      <!--endblock-->                    # End-Delimiter

   |                                   # OR
      (                                  # (4),Take off Unbalanced (delimeter) ERRORS
           <!--
           (?: block: .*? | endblock )
           -->
      )
 )

 # ///////////////////////
 # // Subroutines
 # // ---------------

 (?(DEFINE)

      # core
      (?<core>
           (?>
                (?&content) 
             |  
                (?> <!--block: .*? --> )
                # recurse core
                (?:
                     (?&core) 
                  |  
                )
                <!--endblock-->
           )+
      )

      # content 
      (?<content>
           (?>
                (?!
                     <!--
                     (?: block: .*? | endblock )
                     -->
                )
                . 
           )+
      )

 )

Perl代码：

use strict;
use warnings;

use Data::Dumper;

$/ = undef;
my $content = <DATA>;

# Set the error mode on/off here ..
my $BailOnError = 1;
my $IsError = 0;

my $href = {};

ParseCore( $href,$content );

#print Dumper($href);

print "nn";
print "nBase======================n";
print $href->{content};
print "nFirst======================n";
print $href->{first}->{content};
print "nSecond======================n";
print $href->{first}->{second}->{content};
print "nThird======================n";
print $href->{first}->{second}->{third}->{content};
print "nFourth======================n";
print $href->{first}->{second}->{third}->{fourth}->{content};
print "nFifth======================n";
print $href->{first}->{second}->{third}->{fourth}->{fifth}->{content};
print "nSix======================n";
print $href->{six}->{content};
print "nSeven======================n";
print $href->{six}->{seven}->{content};
print "nEight======================n";
print $href->{six}->{seven}->{eight}->{content};

exit;


sub ParseCore
{
    my ($aref,$core) = @_;
    my ($k,$v);
    while ( $core =~ /(?is)(?:((?&content))|(?><!--block:(.*?)-->)((?&core)|)<!--endblock-->|(<!--(?:block:.*?|endblock)-->))(?(DEFINE)(?<core>(?>(?&content)|(?><!--block:.*?-->)(?:(?&core)|)<!--endblock-->)+)(?<content>(?>(?!<!--(?:block:.*?|endblock)-->).)+))/g )
    {
       if (defined $1)
       {
         # CONTENT
           $aref->{content} .= $1;
       }
       elsif (defined $2)
       {
         # CORE
           $k = $2; $v = $3;
           $aref->{$k} = {};
 #         $aref->{$k}->{content} = $v;
 #         $aref->{$k}->{match} = $&;

           my $curraref = $aref->{$k};
           my $ret = ParseCore($aref->{$k},$v);
           if ( $BailOnError && $IsError ) {
               last;
           }
           if (defined $ret) {
               $curraref->{'#next'} = $ret;
           }
       }
       else
       {
         # ERRORS
           print "Unbalanced '$4' at position = ",$-[0];
           $IsError = 1;

           # Decide to continue here ..
           # If BailOnError is set,just unwind recursion. 
           # -------------------------------------------------
           if ( $BailOnError ) {
              last;
           }
       }
    }
    return $k;
}

#================================================
__DATA__
some html content here top base
<!--block:first-->
    <table border="1" style="color:red;">
    <tr class="lines">
        <td align="left" valign="<--valign-->">
    <b>bold</b><a href="http://www.mewsoft.com">mewsoft</a>
    <!--hello--> <--again--><!--world-->
    some html content here 1 top
    <!--block:second-->
        some html content here 2 top
        <!--block:third-->
            some html content here 3 top
            <!--block:fourth-->
                some html content here 4 top
                <!--block:fifth-->
                    some html content here 5a
                    some html content here 5b
                <!--endblock-->
            <!--endblock-->
            some html content here 3a
            some html content here 3b
        <!--endblock-->
        some html content here 2 bottom
    <!--endblock-->
    some html content here 1 bottom
<!--endblock-->
some html content here1-5 bottom base

some html content here 6-8 top base
<!--block:six-->
    some html content here 6 top
    <!--block:seven-->
        some html content here 7 top
        <!--block:eight-->
            some html content here 8a
            some html content here 8b
        <!--endblock-->
        some html content here 7 bottom
    <!--endblock-->
    some html content here 6 bottom
<!--endblock-->
some html content here 6-8 bottom base

输出>>

Base======================
some html content here top base

some html content here1-5 bottom base

some html content here 6-8 top base

some html content here 6-8 bottom base

First======================

    <table border="1" style="color:red;">
    <tr class="lines">
        <td align="left" valign="<--valign-->">
    <b>bold</b><a href="http://www.mewsoft.com">mewsoft</a>
    <!--hello--> <--again--><!--world-->
    some html content here 1 top

    some html content here 1 bottom

Second======================

        some html content here 2 top

        some html content here 2 bottom

Third======================

            some html content here 3 top

            some html content here 3a
            some html content here 3b

Fourth======================

                some html content here 4 top


Fifth======================

                    some html content here 5a
                    some html content here 5b

Six======================

    some html content here 6 top

    some html content here 6 bottom

Seven======================

        some html content here 7 top

        some html content here 7 bottom

Eight======================

            some html content here 8a
            some html content here 8b