GitHub - scala/scala-parser-combinators: simple combinator-based parsing for Scala. formerly part of the Scala standard library, now a separate community-maintained module (original) (raw)

scala-parser-combinators

build

This was originally part of the Scala standard library, but is now community-maintained, under the guidance of the Scala team at Akka (formerly Lightbend). If you are interested in joining the maintainers team, please contact @Philippus or @SethTisue.

Choosing a parsing library

This library's main strengths are:

Its main weaknesses are:

A number of other parsing libraries for Scala are available -- see list on Scaladex.

Documentation

Adding an sbt dependency

To depend on scala-parser-combinators in sbt, add something like this to your build.sbt:

libraryDependencies += "org.scala-lang.modules" %% "scala-parser-combinators" % <version>

To support multiple Scala versions, see the example in scala/scala-module-dependency-sample.

Scala.js and Scala Native

Scala-parser-combinators is also available for Scala.js and Scala Native:

libraryDependencies += "org.scala-lang.modules" %%% "scala-parser-combinators" % <version>

Example

import scala.util.parsing.combinator._

case class WordFreq(word: String, count: Int) { override def toString = s"Word <$word> occurs with frequency $count" }

class SimpleParser extends RegexParsers { def word: Parser[String] = """[a-z]+""".r ^^ { _.toString } def number: Parser[Int] = """(0|[1-9]\d*)""".r ^^ { _.toInt } def freq: Parser[WordFreq] = word ~ number ^^ { case wd ~ fr => WordFreq(wd,fr) } }

object TestSimpleParser extends SimpleParser { def main(args: Array[String]) = { parse(freq, "johnny 121") match { case Success(matched,) => println(matched) case Failure(msg,) => println(s"FAILURE: $msg") case Error(msg,_) => println(s"ERROR: $msg") } } }

For a detailed unpacking of this example seeGetting Started.

Contributing