标记为泛型，包含$ eq [英] Labelled Generic containing `$eq`

问题描述

Shapeless 2.3.3 LabelledGeneric在以下案例类中运行时返回奇怪的结果:

Shapeless 2.3.3 LabelledGeneric returns a curious result when run on the following case class:

scala> case class Foo(`$eq`: Int)
defined class Foo

scala> LabelledGeneric[Foo]
res0: shapeless.LabelledGeneric[Foo]{type Repr = Int with shapeless.labelled.KeyTag[Symbol with shapeless.tag.Tagged[String("=")],Int] :: shapeless.HNil} = shapeless.LabelledGeneric$$anon$1@1ac7dbd3

请注意，返回的标签实际上是=而不是$eq.

Note the label returned is literally = instead of $eq.

此行为是无形的怪癖还是其他?还有其他标识符名称会导致异常行为吗?

Is this behaviour a quirk of shapeless or something else? Are there other identifier names that result in weird behaviour?

我需要MongoDB序列化，这让我头疼……

I require this for MongoDB serialization and this kind of a major headache for me ...

推荐答案

根据Q中Alexey的评论，由于scala/java互操作的工作方式，这是Shapeless的功能".后者在 Daniel Spiewak的污点文章中进行了解释操作员和超负荷工作".

As per Alexey's comment in the Q, this is a 'feature' in Shapeless, because of the way scala/java interop works. The latter is explained in Daniel Spiewak's blot post under "operators and overaloading".

这会影响每个博客的运营商列表:

The list of operators, per the blog, that this affects are:

op  Compiles To
=   $eq
>   $greater
<   $less
+   $plus
-   $minus
*   $times
/   div
!   $bang
@   $at
#   $hash
%   $percent
^   $up
&   $amp
~   $tilde
?   $qmark
|   $bar
\   $bslash
:   $colon

这篇关于标记为泛型，包含$ eq的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！