Out of memory error when parsing with rep combinator applied to "a*" regular expression

Hi,

When constructing either of the following parsers-- rep("a*".r) or
repsep("a*".r, ""), both parsers run into out of memory errors when
parsing the input "a". I realize these are rather perverse parsers,
but I am not sure attempting to use them should result in out of
memory errors.

Scala code runner version 2.9.0.final -- Copyright 2002-2011, LAMP/
EPFL

My test code and stack trace is below:

Thanks!

--Adrian

----

import scala.util.parsing.combinator.RegexParsers

object ReStarRepTest extends RegexParsers {

def testRep: Boolean = {
val re = "a*".r
val repRe = rep(re)
val inLangStr = "a"
parseAll(repRe, inLangStr) match {
case Success(_, _) => true
case NoSuccess(_, _) => false
}
}

def testEmptyRepSep: Boolean = {
val re = "a*".r
val repRe = repsep(re, "")
val inLangStr = "a"
parseAll(repRe, inLangStr) match {
case Success(_, _) => true
case NoSuccess(_, _) => false
}
}

def main(args: Array[String]) {
// Tests if "a" is language of rep(a*)
assert(testRep)

// Tests if "a" is in language of repsep(a*, "")
assert(testEmptyRepSep)
}
}

----

java.lang.OutOfMemoryError: GC overhead limit exceeded
at scala.util.parsing.combinator.RegexParsers$$anon
$2.apply(RegexParsers.scala:63)
at scala.util.parsing.combinator.Parsers$$anonfun$rep1$1.applyp
$1(Parsers.scala:594)
at scala.util.parsing.combinator.Parsers$$anonfun$rep1$1.continue
$1(Parsers.scala:599)
at scala.util.parsing.combinator.Parsers$$anonfun
$rep1$1.apply(Parsers.scala:603)
at scala.util.parsing.combinator.Parsers$$anonfun
$rep1$1.apply(Parsers.scala:588)
at scala.util.parsing.combinator.Parsers$$anon$3.apply(Parsers.scala:
183)
at scala.util.parsing.combinator.Parsers$Parser$$anonfun$append
$1.apply(Parsers.scala:210)
at scala.util.parsing.combinator.Parsers$Parser$$anonfun$append
$1.apply(Parsers.scala:210)
at scala.util.parsing.combinator.Parsers$$anon$3.apply(Parsers.scala:
183)
at scala.util.parsing.combinator.Parsers$Parser$$anonfun$flatMap
$1.apply(Parsers.scala:201)
at scala.util.parsing.combinator.Parsers$Parser$$anonfun$flatMap
$1.apply(Parsers.scala:201)
at scala.util.parsing.combinator.Parsers$$anon$3.apply(Parsers.scala:
183)
at scala.util.parsing.combinator.Parsers$$anon$2.apply(Parsers.scala:
754)
at scala.util.parsing.combinator.RegexParsers
$class.parse(RegexParsers.scala:100)
at ReStarRepTest$.parse(ReStarRepTest.scala:3)
at scala.util.parsing.combinator.RegexParsers
$class.parseAll(RegexParsers.scala:116)
at ReStarRepTest$.parseAll(ReStarRepTest.scala:3)
at ReStarRepTest$.testRep(ReStarRepTest.scala:9)
at ReStarRepTest$.main(ReStarRepTest.scala:27)
at ReStarRepTest.main(ReStarRepTest.scala)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:
57)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:
43)
at java.lang.reflect.Method.invoke(Method.java:616)
at scala.tools.nsc.util.ScalaClassLoader$$anonfun$run
$1.apply(ScalaClassLoader.scala:78)
at scala.tools.nsc.util.ScalaClassLoader
$class.asContext(ScalaClassLoader.scala:24)
at scala.tools.nsc.util.ScalaClassLoader
$URLClassLoader.asContext(ScalaClassLoader.scala:88)
at scala.tools.nsc.util.ScalaClassLoader
$class.run(ScalaClassLoader.scala:78)
at scala.tools.nsc.util.ScalaClassLoader
$URLClassLoader.run(ScalaClassLoader.scala:101)
at scala.tools.nsc.ObjectRunner$.run(ObjectRunner.scala:33)
at scala.tools.nsc.ObjectRunner$.runAndCatch(ObjectRunner.scala:40)
at scala.tools.nsc.MainGenericRunner.runTarget
$1(MainGenericRunner.scala:56)