perl6如何在正则表达式内插中使用结点? [英] perl6 How to use junction inside regex interpolation?

问题描述

有时我的列表很长，我想检查字符串是否与列表中的任何内容匹配.我试图在正则表达式内插值.它们都是错误.

Sometimes I have a long list and I would like to check whether a string matches anything in the list. I am trying to interpolate a junction inside a regex. They are all errors.

say "12345" ~~ m/ <{ (2,3,4).any }> /
Cannot resolve caller MAKE_REGEX(Int, Bool, Bool, Int, PseudoStash); none of these signatures match:

say "12345" ~~ m/ $( (2,3,4).any ) /
This type cannot unbox to a native string: P6opaque, Junction

此错误消息是否表示不能在正则表达式内插中使用结点?

Does this error message mean that junctions cannot be used inside regex interpolation?

我的解决方法是

say "12345" ~~ m/ <{ (2,3,4).join("||") }> /
｢2｣

关于在正则表达式内插中使用结点的任何建议吗?

Any suggestions as to use junctions inside regex interpolation?

非常感谢您！

lisprog

推荐答案

有时我的清单很长，我想检查字符串是否与清单中的任何内容匹配.

Sometimes I have a long list and I would like to check whether a string matches anything in the list.

使用列表，而不是连接点:

Use a list, not a Junction:

my @list = <bar bartoo baragain>;
say 'bartoo' ~~ / @list /;                         # ｢bartoo｣
say 'bartoo' ~~ / <{<bar bartoo baragain>}> /;     # ｢bartoo｣

请注意，默认情况下，您会获得最长的匹配令牌.

Note that by default you get the longest matching token.

我正在尝试在正则表达式内插值.它们都是错误....此错误消息是否表示不能在正则表达式内插中使用结点?

I am trying to interpolate a junction inside a regex. They are all errors. ... Does this error message mean that junctions cannot be used inside regex interpolation?

我是这样认为的.(错误消息可能是LTA.)连接点是主要P6语言的功能.匹配 DSL 的模式不支持它们，这似乎是合理的.

I think so. (The error message is perhaps LTA.) Junctions are a feature of the main P6 language. It seems reasonable that the pattern matching DSL doesn't support them.

我的解决方法是

say "12345" ~~ m/ <{ (2,3,4).join("||") }> /
｢2｣

如果您使用双倍的管道( || )加入，则将获得第一个匹配的令牌，而不是最长的令牌:

If you join with a doubled pipe (||) then you get the first token that matches rather than the longest:

say 'bartoo' ~~ / <{'bar || bartoo || baragain'}> /; # ｢bar｣
say 'bartoo' ~~ / ||@list /;                         # ｢bar｣
say 'bartoo' ~~ / ||<{<bar bartoo baragain>}> /;     # ｢bar｣

不为这些构造指定管道符号与指定单个管道符号( | )相同，并且匹配最长匹配标记:

Not specifying the pipe symbol for these constructs is the same as specifying a single pipe symbol (|) and matches the longest matching token:

say 'bartoo' ~~ / <{'bar | bartoo | baragain'}> /; # ｢bartoo｣
say 'bartoo' ~~ / |@list /;                        # ｢bartoo｣
say 'bartoo' ~~ / |<{<bar bartoo baragain>}> /;    # ｢bartoo｣

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您之前曾问过相关问题.为了方便起见，我将在其中添加一些链接:

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You've asked related questions before. I'll add links to a couple of them here for convenience:

• 是否可以使用结点进行匹配?

插值数组匹配AND，OR，NOT功能

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