diff options
| -rw-r--r-- | src/compiler/scala/tools/nsc/transform/patmat/MatchTranslation.scala | 20 |
1 files changed, 11 insertions, 9 deletions
diff --git a/src/compiler/scala/tools/nsc/transform/patmat/MatchTranslation.scala b/src/compiler/scala/tools/nsc/transform/patmat/MatchTranslation.scala index 682631b70d..ae406ad8dd 100644 --- a/src/compiler/scala/tools/nsc/transform/patmat/MatchTranslation.scala +++ b/src/compiler/scala/tools/nsc/transform/patmat/MatchTranslation.scala @@ -52,6 +52,11 @@ trait MatchTranslation extends CpsPatternHacks { trait MatchTranslator extends TreeMakers { import typer.context + // a list of TreeMakers that encode `patTree`, and a list of arguments for recursive invocations of `translatePattern` to encode its subpatterns + private case class TranslationStep(makers: List[TreeMaker], subpatterns: List[(Symbol, Tree)]) { + def merge(f: (Symbol, Tree) => List[TreeMaker]): List[TreeMaker] = makers ::: (subpatterns flatMap f.tupled) + } + // Why is it so difficult to say "here's a name and a context, give me any // matching symbol in scope" ? I am sure this code is wrong, but attempts to // use the scopes of the contexts in the enclosing context chain discover @@ -234,15 +239,14 @@ trait MatchTranslation extends CpsPatternHacks { * a function that will take care of binding and substitution of the next ast (to the right). * */ - def translateCase(scrutSym: Symbol, pt: Type)(caseDef: CaseDef) = caseDef match { case CaseDef(pattern, guard, body) => + def translateCase(scrutSym: Symbol, pt: Type)(caseDef: CaseDef) = { + val CaseDef(pattern, guard, body) = caseDef translatePattern(scrutSym, pattern) ++ translateGuard(guard) :+ translateBody(body, pt) } def translatePattern(patBinder: Symbol, patTree: Tree): List[TreeMaker] = { - // a list of TreeMakers that encode `patTree`, and a list of arguments for recursive invocations of `translatePattern` to encode its subpatterns - type TranslationStep = (List[TreeMaker], List[(Symbol, Tree)]) - def withSubPats(treeMakers: List[TreeMaker], subpats: (Symbol, Tree)*): TranslationStep = (treeMakers, subpats.toList) - def noFurtherSubPats(treeMakers: TreeMaker*): TranslationStep = (treeMakers.toList, Nil) + def withSubPats(treeMakers: List[TreeMaker], subpats: (Symbol, Tree)*): TranslationStep = TranslationStep(treeMakers, subpats.toList) + def noFurtherSubPats(treeMakers: TreeMaker*): TranslationStep = TranslationStep(treeMakers.toList, Nil) val pos = patTree.pos @@ -339,7 +343,7 @@ trait MatchTranslation extends CpsPatternHacks { // [6] pattern alternatives // [7] symbol-less bind patterns - this happens in certain ill-formed programs, there'll be an error later // don't fail here though (or should we?) - val (treeMakers, subpats) = patTree match { + val translationStep = patTree match { case WildcardPattern() => none() case UnApply(unfun, args) => translateExtractorPattern(ExtractorCall(unfun, args)) case Apply(fun, args) => ExtractorCall.fromCaseClass(fun, args) map translateExtractorPattern getOrElse noFurtherSubPats() @@ -351,9 +355,7 @@ trait MatchTranslation extends CpsPatternHacks { case _ => context.unit.error(patTree.pos, unsupportedPatternMsg) ; none() } - treeMakers ++ subpats.flatMap { case (binder, pat) => - translatePattern(binder, pat) // recurse on subpatterns - } + translationStep merge translatePattern } def translateGuard(guard: Tree): List[TreeMaker] = |