Commit 895a882

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Merge pull request #65 from liskin/pagedseqreader-packrat

Fix packrat caching with PagedSeqReader

2 parents aacfcf8 + 0345e49 commit 895a882Copy full SHA for 895a882

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+54

-4

lines changed

src
- main/scala/scala/util/parsing/input
  - PagedSeqReader.scala
- test/scala/scala/util/parsing/combinator
  - gh45.scala

+54

-4

lines changed

Lines changed: 8 additions & 4 deletions

Original file line number	Diff line number	Diff line change
`@@ -30,10 +30,10 @@ object PagedSeqReader {`
`30`	`30`	`* @author Martin Odersky`
`31`	`31`	`*/`
`32`	`32`	`class PagedSeqReader(seq: PagedSeq[Char],`
`33`		`- override val offset: Int) extends Reader[Char] {`
	`33`	`+ override val offset: Int) extends Reader[Char] { outer =>`
`34`	`34`	`import PagedSeqReader._`
`35`	`35`
`36`		`- override lazyval source: java.lang.CharSequence = seq`
	`36`	`+ override val source: java.lang.CharSequence = seq`
`37`	`37`
`38`	`38`	/** Construct a `PagedSeqReader` with its first element at
`39`	`39`	* `source(0)` and position `(1,1)`.
`@@ -51,7 +51,9 @@ class PagedSeqReader(seq: PagedSeq[Char],`
`51`	`51`	* otherwise, it's a `PagedSeqReader` containing the rest of input.
`52`	`52`	`*/`
`53`	`53`	`def rest: PagedSeqReader =`
`54`		`- if (seq.isDefinedAt(offset)) new PagedSeqReader(seq, offset + 1)`
	`54`	`+ if (seq.isDefinedAt(offset)) new PagedSeqReader(seq, offset + 1) {`
	`55`	`+ override val source: java.lang.CharSequence = outer.source`
	`56`	`+ }`
`55`	`57`	`else this`
`56`	`58`
`57`	`59`	`/** The position of the first element in the reader.`
`@@ -67,5 +69,7 @@ class PagedSeqReader(seq: PagedSeq[Char],`
`67`	`69`	* `n` elements.
`68`	`70`	`*/`
`69`	`71`	`override def drop(n: Int): PagedSeqReader =`
`70`		`- new PagedSeqReader(seq, offset + n)`
	`72`	`+ new PagedSeqReader(seq, offset + n) {`
	`73`	`+ override val source: java.lang.CharSequence = outer.source`
	`74`	`+ }`
`71`	`75`	`}`

Lines changed: 46 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,46 @@`
	`1`	`+package scala.util.parsing.combinator`
	`2`	`+`
	`3`	`+import scala.util.parsing.input._`
	`4`	`+import scala.collection.immutable.PagedSeq`
	`5`	`+`
	`6`	`+import org.junit.Test`
	`7`	`+import org.junit.Assert.assertTrue`
	`8`	`+`
	`9`	`+import scala.util.parsing.combinator.syntactical.StandardTokenParsers`
	`10`	`+`
	`11`	`+class gh45 {`
	`12`	`+`
	`13`	`+ @Test`
	`14`	`+ def test4: Unit = {`
	`15`	`+ def check(rd: Reader[Char]): Unit = {`
	`16`	`+ val g = new grammar`
	`17`	`+ val p = g.phrase(g.script)`
	`18`	`+ val parseResult = p(new g.lexical.Scanner(rd))`
	`19`	`+ assertTrue(parseResult.isInstanceOf[g.Success[_]])`
	`20`	`+ }`
	`21`	`+`
	`22`	`+ val str = "x once y"`
	`23`	`+ check(new CharSequenceReader(str))`
	`24`	`+ /* Note that this only tests PagedSeq.rest since neither`
	`25`	`+ * PackratReader nor lexical.Scanner override/use the drop method.`
	`26`	`+ */`
	`27`	`+ check(new PagedSeqReader(PagedSeq.fromStrings(List(str))))`
	`28`	`+ }`
	`29`	`+`
	`30`	`+}`
	`31`	`+`
	`32`	`+private final class grammar extends StandardTokenParsers with PackratParsers {`
	`33`	`+ lexical.reserved ++= List("x", "y", "z", "once")`
	`34`	`+`
	`35`	`+ var onceCnt: Int = 0`
	`36`	`+ lazy val once: PackratParser[String] = memo("once") ^? {`
	`37`	`+ case s if onceCnt == 0 =>`
	`38`	`+ onceCnt += 1`
	`39`	`+ s`
	`40`	`+ }`
	`41`	`+`
	`42`	`+ lazy val script: PackratParser[Any] =`
	`43`	`+ ( "x" ~ once ~ "z"`
	`44`	`+ \| "x" ~ once ~ "y"`
	`45`	`+ )`
	`46`	`+}`

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