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author | Denys Shabalin <denys.shabalin@typesafe.com> | 2014-07-02 14:10:42 +0200 |
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committer | Denys Shabalin <denys.shabalin@typesafe.com> | 2014-07-02 14:10:42 +0200 |
commit | 14d1fe0c35f4ab07a0535adbdf8acbcbd1208363 (patch) | |
tree | cdf75636f4f558b94159bd4f25083d8527aa71cd | |
parent | e67146c6e8758b070f6ce4eeb43d289980bfe51a (diff) | |
download | scala-14d1fe0c35f4ab07a0535adbdf8acbcbd1208363.tar.gz scala-14d1fe0c35f4ab07a0535adbdf8acbcbd1208363.tar.bz2 scala-14d1fe0c35f4ab07a0535adbdf8acbcbd1208363.zip |
SI-8703 add support for blocks with just a single expression to quasiquotes
Previously it was impossible to match a block that was constructed as
Block(Nil, term)
Due to the fact that quasiquotes always flatten those into just term. This is
a correct behaviour for construction (for sake of consistency with parser) but
doing it in deconstruction mode make it impossible to match such blocks which
could have been constructed manually somewhere.
To fix this we just disable block flattening in deconstruction mode.
Interestingly enough this doesn't break existing code due to the fact that
quasiquote's block matcher also matches expressions as single-element blocks.
This allows to match single-element blocks with patterns like q"{ $foo }".
3 files changed, 17 insertions, 5 deletions
diff --git a/src/compiler/scala/tools/reflect/quasiquotes/Parsers.scala b/src/compiler/scala/tools/reflect/quasiquotes/Parsers.scala index b68022afd9..460d02c218 100644 --- a/src/compiler/scala/tools/reflect/quasiquotes/Parsers.scala +++ b/src/compiler/scala/tools/reflect/quasiquotes/Parsers.scala @@ -69,9 +69,14 @@ trait Parsers { self: Quasiquotes => override def makeTupleType(trees: List[Tree]): Tree = TupleTypePlaceholder(trees) // q"{ $x }" - override def makeBlock(stats: List[Tree]): Tree = stats match { - case (head @ Ident(name)) :: Nil if isHole(name) => Block(Nil, head) - case _ => super.makeBlock(stats) + override def makeBlock(stats: List[Tree]): Tree = method match { + case nme.apply => + stats match { + case (head @ Ident(name)) :: Nil if isHole(name) => Block(Nil, head) + case _ => super.makeBlock(stats) + } + case nme.unapply => gen.mkBlock(stats, doFlatten = false) + case other => global.abort("unreachable") } // tq"$a => $b" diff --git a/src/reflect/scala/reflect/internal/TreeGen.scala b/src/reflect/scala/reflect/internal/TreeGen.scala index 9066c73393..6e8e992d16 100644 --- a/src/reflect/scala/reflect/internal/TreeGen.scala +++ b/src/reflect/scala/reflect/internal/TreeGen.scala @@ -451,10 +451,10 @@ abstract class TreeGen { def mkSyntheticUnit() = Literal(Constant(())).updateAttachment(SyntheticUnitAttachment) /** Create block of statements `stats` */ - def mkBlock(stats: List[Tree]): Tree = + def mkBlock(stats: List[Tree], doFlatten: Boolean = true): Tree = if (stats.isEmpty) mkSyntheticUnit() else if (!stats.last.isTerm) Block(stats, mkSyntheticUnit()) - else if (stats.length == 1) stats.head + else if (stats.length == 1 && doFlatten) stats.head else Block(stats.init, stats.last) /** Create a block that wraps multiple statements but don't diff --git a/test/files/scalacheck/quasiquotes/TermDeconstructionProps.scala b/test/files/scalacheck/quasiquotes/TermDeconstructionProps.scala index 49ffaff630..07e8f3faac 100644 --- a/test/files/scalacheck/quasiquotes/TermDeconstructionProps.scala +++ b/test/files/scalacheck/quasiquotes/TermDeconstructionProps.scala @@ -246,4 +246,11 @@ object TermDeconstructionProps extends QuasiquoteProperties("term deconstruction assert(f ≈ `new`) assert(argss.isEmpty) } + + property("SI-8703 extract block with single expression") = test { + val q"{ $a }" = Block(Nil, q"1") + val Literal(Constant(1)) = a + val q"{ $b }" = q"2" + val Literal(Constant(2)) = b + } } |