perl while continue

今天发现Perl中原来还有个while-continue这样的循环。其功能是除了在while中进行last语句外，每走一次while循环，再执行
紧接其后的continue语句，甚至包括next语句。并且在while(),括号中的变量是可以在continue中继续使用的，当然也包括$_。比如:

#!/usr/bin/perl

my $temp_file = "tmp.$$";#后缀是进城ID

open (TMP,"> $temp_file") or die("die:$!");
open (INPUT,"< megaliths.dat") or die("die:$!");

while (my $line = <INPUT>) {
#在continue中是undef
my $while = "above";

#根据预设的正则进行过滤，以缩小进一步修改的范围
next unless $line =~ //Q$some_pattern/;#/Q把特殊的正则元字符一般化
$line .= " append";
}
continue{
#即使在next语句后，continue仍然执行
print TMP "In continue $line/n";
print "[$while]/n";
}

close(TMP);
close(INPUT);

open A ,"<w.txt" or die $!;

while (<A>){

next if /5/;
print "1--\$_ is $_\n";
}
continue {print "2--\$_ is $_\n";}

zjzc01:/root/dbi# perl a3.pl
1--$_ is 1

2--$_ is 1

1--$_ is 2

2--$_ is 2

1--$_ is 3

2--$_ is 3

1--$_ is 4

2--$_ is 4

2--$_ is 5

1--$_ is 6

2--$_ is 6

1--$_ is 7

2--$_ is 7

1--$_ is 8

2--$_ is 8

1--$_ is 9

2--$_ is 9

1--$_ is 10

2--$_ is 10