Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Scala parser combinators never use atEnd and sometimes never terminate #5514

Closed
scabug opened this issue Feb 22, 2012 · 1 comment

Comments

@scabug
Copy link

commented Feb 22, 2012

Please see code below. It does not terminate even though the expected result is to stop applying rep when reader is depleted.

import scala.io.Source
import scala.util.parsing.combinator.Parsers
import scala.util.parsing.input.Reader
import scala.util.parsing.input.Position

object DemoApp extends App {
	val parsers = new DemoParsers
	val reader = new DemoReader(10)
	val result = parsers.startsWith("s").*(reader)
	Console println result
}

class DemoReader(n: Int) extends Reader[String] {
	def atEnd = n == 0
	def first = "s" + n
	def rest = new DemoReader(n - 1)
	def pos = new Position { def line = 0; def column = 0; def lineContents = first }
}

class DemoParsers extends Parsers {
	type Elem = String
	def startsWith(prefix: String) = acceptIf(_ startsWith prefix)("Error: " + _)
}
@scabug

This comment has been minimized.

Copy link
Author

commented Feb 22, 2012

Imported From: https://issues.scala-lang.org/browse/SI-5514?orig=1
Reporter: Tymur Porkuian (fixpoint)
Affected Versions: 2.9.1

@scabug scabug closed this May 7, 2012

@scabug scabug added the minimized label Apr 7, 2017

@scabug scabug added this to the 2.10.0-M3 milestone Apr 7, 2017

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Projects
None yet
2 participants
You can’t perform that action at this time.