相关疑难解决方法(0)

我是Perl 6的新手.我的Atom编辑器中有以下代码,但我仍然不明白它是如何工作的.我复制了以下代码,正如doc.perl6.org所说,但它似乎无法正常工作.所以我把代码更改为:

use v6;

class HTTPHeader { ... }

class HTTPHeader does Associative  {

    has %!fields  handles <self.AT-KEY self.EXISTS-KEY self.DELETE-KEY self.push
                          list kv keys values>;
    method Str { say self.hash.fmt; }


    multi method EXISTS-KEY ($key)       { %!fields{normalize-key $key}:exists }
    multi method DELETE-KEY ($key)       { %!fields{normalize-key $key}:delete }
    multi method push (*@_)              { %!fields.push: @_                   }

    sub normalize-key ($key) { $key.subst(/\w+/, *.tc, :g) } 

    method AT-KEY (::?CLASS:D: $key) is rw {
        my $element := %!fields{normalize-key $key};

        Proxy.new(
            FETCH => …