Scala外部DSL-多行字符串文字 [英] Scala External DSL -- Multi line string literal

问题描述

我正在尝试使用scala解析器组合器定义外部DSL。我发现'stringLit'令牌解析器不能使用三重引号来容纳多行字符串。 Scala解析器组合器世界中是否有类似于multiLineStringLit的东西？

I am trying to define an external DSL using the scala parser combinators. I see that the 'stringLit' token parser does not accomodate multi line strings using the triple quotes. Is there something similar to a multiLineStringLit in the scala parser combinator world?

预先感谢，
Kishore

Thanks in advance, Kishore

推荐答案

不是我所知道的，但是编写自己的并不难：

Not that I'm aware of, but it's not too hard to write your own:

import scala.util.parsing.combinator._

object myParser extends JavaTokenParsers {
  def mlStringLiteral: Parser[String] = (
    "\"\"\"" +
    """(\n|[^"\p{Cntrl}\\]|\\[\\/bfnrt]|\\u[a-fA-F0-9]{4})*""" +
    "\"\"\""
  ).r
}

这只是 stringLiteral 进行了一些小修改：我将分隔符从 更改为 ，并添加了 \n 匹配字符。

This is just stringLiteral with a couple of minor edits: I've changed the delimiter from " to """ and added \n to the character match.

scala> val s = "\"\"\"This is a multi-\nline string literal.\"\"\""
s: java.lang.String = 
"""This is a multi-
line string literal."""

scala> myParser.parseAll(myParser.mlStringLiteral, s)
res0: myParser.ParseResult[String] = 
[2.24] parsed: """This is a multi-
line string literal."""

这与Scala的多行字符串文字的实现不完全匹配（您不能例如，字符串中未转义的 ），但可以轻松对其进行调整，并且可能对您有用。

It's not an exact match for Scala's implementation of multi-line string literals (you can't have an unescaped " in the string, for example), but it can easily be tweaked, and may work for you as it is.

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