在Raku中使用Perl 5模块的Data :: Printer的show_tied选项时，该如何关闭? [英] How do I turn the Perl 5 module Data::Printer's `show_tied` option off when using it in Raku?

问题描述

我已经在Perl中使用了CPAN Perl模块Data :: Printer(DP).效果很好.

I've used the CPAN Perl module Data::Printer (DP) with Perl. It works great.

现在我想在Raku代码中使用它.

Now I want to use it in Raku code.

当我使用:from<Perl5>功能导入它，然后使用它运行代码时，注释(tied to Perl6::Hash)会附加到散列的显示中. ¹

When I use the :from<Perl5> feature to import it and then run code using it, the annotation (tied to Perl6::Hash) is appended to the display of hashes.¹

如 DP的CPAN文档所示，此注释由选项show_tied控制.我想将其设置为 off (将其设置为0)，而不是将其默认的 on (设置为1).这是我在Perl中的做法:

As DP's CPAN doc shows, this annotation is controlled by the option show_tied. I want to switch it off (set it to 0) instead of its default on (set to 1). Here's how I'd do that in Perl:

use Data::Printer show_tied => 0;

但是当我在Raku中尝试时:

But when I try this in Raku:

use Data::Printer:from<Perl5> show_tied => 0;

我得到:

从'Data :: Printer'导入时出错:没有这样的标签'show_tied'

Error while importing from 'Data::Printer': no such tag 'show_tied'

在Raku中使用DP时如何关闭show_tied?

How do I turn show_tied off when using DP in Raku?

¹ 也许是因为 Inline :: Perl5 (其中实现:from<Perl5>功能)正在做一些事情来启用平滑的Perl/Raku互操作.

¹ Perhaps this is because Inline::Perl5 (which implements the :from<Perl5> feature) is doing something to enable smooth Perl/Raku interop.

推荐答案

在Raku中使用DP时如何关闭show_tied?

您必须明确转换 Associative (例如列在use语句末尾的 not "tags"，到一个扁平的列表，交错键和值. ¹

You must explicitly convert Associatives (eg Pairs) that are listed at the end of a use statement, that are not "tags", to a flattened list interleaving keys and values.¹

最直接的解决方案是手动编写平面文字列表，例如:

The most direct solution is to manually write a flat list of literals, eg:

use Data::Printer:from<Perl5> 'show_tied', 0;

有关更整洁的解决方案，请参阅下面的使用kv 部分.

For a neater solution, see the Using kv section below.

请注意，use语句是在编译时求值的.因此，如果要在列表中注入变量，则需要确保在评估use语句之前，在 compile-time 处建立了它们的值，而不仅仅是它们的名称.没有修饰的my $foo = 0;是不够的，因为= 0部分将在运行时发生.相反，您将需要使用合适的编译时结构，例如 BEGIN :

Note that use statements are evaluated at compile-time. So if you want to inject variables in the list then you need to ensure that their values, not just their names, are also established at compile-time, before the use statement is evaluated. An unadorned my $foo = 0; will not suffice because the = 0 part will happen at run-time. Instead you will need to use a suitable compile-time construct such as BEGIN:

BEGIN my $foo = 0;
use Data::Printer:from<Perl5> 'show_tied', $foo;

使用kv

kv例程可以生成所需的'key1', value1, 'key2', value2, ...给定哈希值的序列:

Using kv

The kv routine can generate the desired 'key1', value1, 'key2', value2, ... sequence given a hash:

use Data::Printer:from<Perl5> kv { show_tied => 0 }

或:

BEGIN my %opts = show_tied => 0;
use Data::Printer:from<Perl5> kv %opts;

脚语

¹ 此答案基于Stefan从该问题的解释我响应在Raku中Data :: Printer中的更改参数" SO :

Footnotes

¹ This answer built upon Stefan's explanation from the issue I opened in response to the "Altering parameters in Data::Printer in Raku" SO:

解决方案非常简单:使用Data::Printer:from<Perl5> 'show_tied', 0;胖逗号=>是Raku中的Pair构造函数，而实际上在Perl 5中只是花哨的逗号.Raku认为Pair参数用于导入标签.类似于:ALL(等效于ALL => True).要解决此问题并传递Perl 5代码的期望，只需单独列出这些值即可.

The solution is rather simple: use Data::Printer:from<Perl5> 'show_tied', 0; The fat comma => is a Pair constructor in Raku while it's really just a fancy comma in Perl 5. Raku considers Pair arguments to be used for importing tags like :ALL (which is equivalent to ALL => True). To get around this and pass what Perl 5 code expects, just list the values individually.

换句话说，这种转换的需要是因为Perl和Raku共享标签的概念(; 有关标签"的Raku文档)，并且(并非偶然)习惯性地使用相同的语法来选择标签(:tagname).

In other words, this need for conversion is because Perl and Raku share the notion of tags (Perl doc about "tags"; Raku doc about "tags") and (not coincidentally) idiomatically use the same syntax for selecting tags (:tagname).

此外，使用Raku，这个问题(需要解决)之间的歧义(是否需要使用语法来指定标签)适用于在顶层广告代码中使用的 all Associative use语句，不仅是用:foo形式编写的语句，甚至还包括用foo => bar，{ foo => bar}，%baz或{ %baz }等其他形式编写的语句.

Furthermore, using Raku, this issue of (the need to resolve) ambiguity between whether syntax is being used to specify tags or not applies to all Associatives used in the top level of a use statement, not just ones written in the form :foo but even ones written in other forms such as foo => bar, { foo => bar}, %baz, or { %baz }.

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