@list = split /(?=PATTERN)/;

##</code><code>##

my $pat = qr/^[ \t]*[^\s:]+:[ \t]*$/m;  # allow leading/trailing ws
my $pat = qr/^[^\s:]+:/m;

$_ = slurp_file;
my @stanzas = split /(?=$pat)/o;

##</code><code>##

@list = /( .*? PATTERN | .+ )/gsx;

##</code><code>##

my $pat = qr/(?:^[ \t]*\n)+(?:[ \t]+\z)?/m;

$_ = slurp_file;
my @list = /( .*? $pat | .+ )/ogsx;

##</code><code>##

my @list = split /^\s*(?:\n|\z)/m;
shift @list if @list && $list[0] eq "";  # remove empty first element

##</code><code>##

my $delim = qr/^[ \t]*SOMETHING[ \t]*$/m;
my $pat   = qr/$delim(?:\n[ \t]*)*(?:\n|\z)/o;

##</code><code>##

# Partition a string into paragraphs based on a 
# pattern which matches the beginning of a paragraph.
sub partition_para_beg {
   my ($pat, $str) = @_;
   $str = $_ unless defined $str;
   if ("" =~ /$pat/) {
      require Carp;
      Carp::croak("invalid pattern matches empty string: \"$pat\"\n");
   }
   split /(?=$pat)/;
}

# Partition a string into paragraphs based on a 
# pattern which matches the end of a paragraph.
sub partition_para_end {
   my ($pat, $str) = @_;
   $str = $_ unless defined $str;
   if ("" =~ /$pat/) {
      require Carp;
      Carp::croak("invalid pattern matches empty string: \"$pat\"\n");
   }
   return $str =~ /(.*?(?:$pat)|.+)/gs;
}