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author | Stephen Judkins <stephen.judkins@gmail.com> | 2012-01-21 17:08:52 -0800 |
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committer | Stephen Judkins <stephen.judkins@gmail.com> | 2012-01-21 17:08:52 -0800 |
commit | dce6b34c38a6d774961ca6f9fd50b11300ecddd6 (patch) | |
tree | 449361e5c2936c67370e85ebc97844371201187d /src/library | |
parent | 8051740e1be3b33081b2179d1d1fd35a4c8b5c84 (diff) | |
download | scala-dce6b34c38a6d774961ca6f9fd50b11300ecddd6.tar.gz scala-dce6b34c38a6d774961ca6f9fd50b11300ecddd6.tar.bz2 scala-dce6b34c38a6d774961ca6f9fd50b11300ecddd6.zip |
Fixes SI-4929, with a test to verify.
Also fixes potential issue with Parsers.phrase not being reentrant; however, I was unable to actually reproduce this issue in practice. (The order in which lastNoSuccess was being set and compared seemed to guarantee that it would never actually be a problem).
Diffstat (limited to 'src/library')
-rw-r--r-- | src/library/scala/util/parsing/combinator/Parsers.scala | 29 |
1 files changed, 15 insertions, 14 deletions
diff --git a/src/library/scala/util/parsing/combinator/Parsers.scala b/src/library/scala/util/parsing/combinator/Parsers.scala index 4004a01ad9..70c92342b4 100644 --- a/src/library/scala/util/parsing/combinator/Parsers.scala +++ b/src/library/scala/util/parsing/combinator/Parsers.scala @@ -12,6 +12,7 @@ import scala.util.parsing.input._ import scala.collection.mutable.ListBuffer import scala.annotation.tailrec import annotation.migration +import scala.util.DynamicVariable // TODO: better error handling (labelling like parsec's <?>) @@ -153,13 +154,14 @@ trait Parsers { val successful = true } - var lastNoSuccess: NoSuccess = null + private lazy val lastNoSuccess = new DynamicVariable[Option[NoSuccess]](None) /** A common super-class for unsuccessful parse results. */ sealed abstract class NoSuccess(val msg: String, override val next: Input) extends ParseResult[Nothing] { // when we don't care about the difference between Failure and Error val successful = false - if (!(lastNoSuccess != null && next.pos < lastNoSuccess.next.pos)) - lastNoSuccess = this + + if (lastNoSuccess.value map { v => !(next.pos < v.next.pos) } getOrElse true) + lastNoSuccess.value = Some(this) def map[U](f: Nothing => U) = this def mapPartial[U](f: PartialFunction[Nothing, U], error: Nothing => String): ParseResult[U] = this @@ -487,7 +489,7 @@ trait Parsers { } /** Changes the error message produced by a parser. - * + * * This doesn't change the behavior of a parser on neither * success nor failure, just on error. The semantics are * slightly different than those obtained by doing `| error(msg)`, @@ -877,16 +879,15 @@ trait Parsers { * if `p` consumed all the input. */ def phrase[T](p: Parser[T]) = new Parser[T] { - lastNoSuccess = null - def apply(in: Input) = p(in) match { - case s @ Success(out, in1) => - if (in1.atEnd) - s - else if (lastNoSuccess == null || lastNoSuccess.next.pos < in1.pos) - Failure("end of input expected", in1) - else - lastNoSuccess - case _ => lastNoSuccess + def apply(in: Input) = lastNoSuccess.withValue(None) { + p(in) match { + case s @ Success(out, in1) => + if (in1.atEnd) + s + else + lastNoSuccess.value filterNot { _.next.pos < in1.pos } getOrElse Failure("end of input expected", in1) + case ns => lastNoSuccess.value.getOrElse(ns) + } } } |