Question

我想使用Class生成json行，我会覆盖gist方法，以便打印出我想要的内容：

my $ak = '7111ac873c9dcd5fc335ded47630d050';
my $st = '1523451601875';
my $ifo = 'true';
my $uu = "15778787898988090";

class Stay {
  has $.ak  is rw = '7111ac873c9dcd5fc335ded47630d050';
  has $.uu  is rw;
  has $.ifo is rw;
  has $.st  is rw;

  method gist() {
    #return qqww/{"ev":"app","ak":"$!ak","uu":"$!uu","ifo":"$!ifo","st":"$!st"}/;

    return qqww:to「EOF」;
    {"ev":"app","ak":"$!ak","uu":"$!uu","ifo":"$!ifo","st":"$!st"}
    EOF
  }
}

say Stay.new(uu => $uu, ifo => $ifo, st => $st);

但失败了：

===SORRY!=== Error while compiling /Users/ohmycloud/Desktop/stay.pl6
Confused
at /Users/ohmycloud/Desktop/stay.pl6:18
------>     {"ev":⏏"app","ak":"$!ak","uu":"$!uu","ifo":"$!i
    expecting any of:
        colon pair

我想要的是：

{"ev":"app","ak":"7111ac873c9dcd5fc335ded47630d050","uu":"15778787898988090","ifo":"true","st":"1523451601875"}

为什么我不能在qqww或qq:to结构中使用冒号对？

Answer 1

{}在双引号中有特殊含义。他们必须逃脱

qq:to「EOF」;
\{"ev":"app","ak":"$!ak","uu":"$!uu","ifo":"$!ifo","st":"$!st"\}
EOF

您需要qq，而不是列出的qqww。

您可以使用fmt

(:ev<app>, :$!ak, :$!uu, :$!ifo, :$!st).fmt('"%s":"%s"', ',').fmt('{%s}')

或JSON::Fast

require JSON::Fast <&to-json>;
{:ev<app>, :$!ak, :$!uu, :$!ifo, :$!st}.&to-json

甚至

require JSON::Fast <&to-json>;
self.^attributes.map( {.name => .get_value(self)} ).Hash.&to-json

Answer 2

您可以使用unquoting：

index

将返回

method gist() {
    return '{"ev":"app","ak":"\qq[$!ak]","uu":"\qq[$!uu]","ifo":"\qq[$!ifo]","st":"\qq[$!st]"}':
}

如果你使用{"ev":"app","ak":"7111ac873c9dcd5fc335ded47630d050","uu":"15778787898988090","ifo":"true","st":"1523451601875"}或类似的话，冒号会妨碍你。

不能在`qqww`或`qqww：to`结构中使用冒号对

2 个答案: