add support for for loops and for enumerators to quasiquotes

1. q"for (..$enums) $body", q"for (..$enums) yield $body"

2. fq"..." quote to construct/deconstruct enumerators

6 files changed, 49 insertions, 5 deletions

diff --git a/src/compiler/scala/tools/reflect/quasiquotes/Parsers.scala b/src/compiler/scala/tools/reflect/quasiquotes/Parsers.scala
index f9ecbe35c9..d8ede24f1a 100644
--- a/src/compiler/scala/tools/reflect/quasiquotes/Parsers.scala
+++ b/src/compiler/scala/tools/reflect/quasiquotes/Parsers.scala
@@ -152,6 +152,13 @@ trait Parsers { self: Quasiquotes =>
           in.nextToken()
           stats
       }
+
+      override def enumerator(isFirst: Boolean, allowNestedIf: Boolean = true) =
+        if (isHole && lookingAhead { in.token == EOF || in.token == RPAREN || isStatSep }) {
+          val res = build.SyntacticValFrom(Bind(in.name, Ident(nme.WILDCARD)), Ident(nme.QUASIQUOTE_FOR_ENUM)) :: Nil
+          in.nextToken()
+          res
+        } else super.enumerator(isFirst, allowNestedIf)
     }
   }
 
@@ -174,11 +181,21 @@ trait Parsers { self: Quasiquotes =>
     }
   }
 
+  object ForEnumeratorParser extends Parser {
+    def entryPoint = { parser =>
+      val enums = parser.enumerator(isFirst = false, allowNestedIf = false)
+      assert(enums.length == 1)
+      enums.head
+    }
+  }
+
   object FreshName {
     def unapply(name: Name): Option[String] =
-      name.toString.split("\\$") match {
-        case Array(qq, left, right) if qq + "$" == nme.QUASIQUOTE_PREFIX && Try(right.toInt).isSuccess =>
-          Some(left + "$")
+      name.toString.split("\\$").toSeq match {
+        case qq +: (middle :+ last)
+          if qq + "$" == nme.QUASIQUOTE_PREFIX
+          && Try(last.toInt).isSuccess && middle.nonEmpty =>
+          Some(middle.mkString("", "$", "$"))
         case _ =>
           None
       }
diff --git a/src/compiler/scala/tools/reflect/quasiquotes/Placeholders.scala b/src/compiler/scala/tools/reflect/quasiquotes/Placeholders.scala
index c31d1fcd12..54be9123c7 100644
--- a/src/compiler/scala/tools/reflect/quasiquotes/Placeholders.scala
+++ b/src/compiler/scala/tools/reflect/quasiquotes/Placeholders.scala
@@ -161,4 +161,12 @@ trait Placeholders { self: Quasiquotes =>
       case _ => None
     }
   }
+
+  object ForEnumPlaceholder {
+    def unapply(tree: Tree): Option[(Tree, Location, Cardinality)] = tree match {
+      case build.SyntacticValFrom(Bind(Placeholder(tree, location, card), Ident(nme.WILDCARD)), Ident(nme.QUASIQUOTE_FOR_ENUM)) =>
+        Some((tree, location, card))
+      case _ => None
+    }
+  }
 }
\ No newline at end of file
diff --git a/src/compiler/scala/tools/reflect/quasiquotes/Quasiquotes.scala b/src/compiler/scala/tools/reflect/quasiquotes/Quasiquotes.scala
index f4d6b39d02..7d777ef7d5 100644
--- a/src/compiler/scala/tools/reflect/quasiquotes/Quasiquotes.scala
+++ b/src/compiler/scala/tools/reflect/quasiquotes/Quasiquotes.scala
@@ -31,6 +31,7 @@ abstract class Quasiquotes extends Parsers
         case nme.tq      => TypeParser.parse(_)
         case nme.cq      => CaseParser.parse(_)
         case nme.pq      => PatternParser.parse(_)
+        case nme.fq      => ForEnumeratorParser.parse(_)
         case other       => global.abort(s"Unknown quasiquote flavor: $other")
       }
       (universe0, args0, parts1, parse0, reify0, method0)
diff --git a/src/compiler/scala/tools/reflect/quasiquotes/Reifiers.scala b/src/compiler/scala/tools/reflect/quasiquotes/Reifiers.scala
index 3d1ecf95b2..b28c85cfc2 100644
--- a/src/compiler/scala/tools/reflect/quasiquotes/Reifiers.scala
+++ b/src/compiler/scala/tools/reflect/quasiquotes/Reifiers.scala
@@ -127,6 +127,7 @@ trait Reifiers { self: Quasiquotes =>
       case RefineStatPlaceholder(tree, _, _) => reifyRefineStat(tree)
       case EarlyDefPlaceholder(tree, _, _) => reifyEarlyDef(tree)
       case PackageStatPlaceholder(tree, _, _) => reifyPackageStat(tree)
+      case ForEnumPlaceholder(tree, _, _) => tree
       case _ => EmptyTree
     }
 
@@ -148,6 +149,16 @@ trait Reifiers { self: Quasiquotes =>
         reifyBuildCall(nme.SyntacticValDef, mods, name, tpt, rhs)
       case SyntacticVarDef(mods, name, tpt, rhs) =>
         reifyBuildCall(nme.SyntacticVarDef, mods, name, tpt, rhs)
+      case SyntacticValFrom(pat, rhs) =>
+        reifyBuildCall(nme.SyntacticValFrom, pat, rhs)
+      case SyntacticValEq(pat, rhs) =>
+        reifyBuildCall(nme.SyntacticValEq, pat, rhs)
+      case SyntacticFilter(cond) =>
+        reifyBuildCall(nme.SyntacticFilter, cond)
+      case SyntacticFor(enums, body) =>
+        reifyBuildCall(nme.SyntacticFor, enums, body)
+      case SyntacticForYield(enums, body) =>
+        reifyBuildCall(nme.SyntacticForYield, enums, body)
       case SyntacticAssign(lhs, rhs) =>
         reifyBuildCall(nme.SyntacticAssign, lhs, rhs)
       case SyntacticApplied(fun, List(args))
@@ -275,7 +286,7 @@ trait Reifiers { self: Quasiquotes =>
       case RefineStatPlaceholder(tree, _, DotDot) => reifyRefineStat(tree)
       case EarlyDefPlaceholder(tree, _, DotDot) => reifyEarlyDef(tree)
       case PackageStatPlaceholder(tree, _, DotDot) => reifyPackageStat(tree)
-
+      case ForEnumPlaceholder(tree, _, DotDot) => tree
       case List(Placeholder(tree, _, DotDotDot)) => tree
     } {
       reify(_)
diff --git a/src/reflect/scala/reflect/api/Quasiquotes.scala b/src/reflect/scala/reflect/api/Quasiquotes.scala
index 3687ccba63..fcf8edcec7 100644
--- a/src/reflect/scala/reflect/api/Quasiquotes.scala
+++ b/src/reflect/scala/reflect/api/Quasiquotes.scala
@@ -14,5 +14,6 @@ trait Quasiquotes { self: Universe =>
     object tq extends api
     object cq extends api
     object pq extends api
+    object fq extends api
   }
 }
diff --git a/src/reflect/scala/reflect/internal/StdNames.scala b/src/reflect/scala/reflect/internal/StdNames.scala
index bc9c46a141..c26e815df1 100644
--- a/src/reflect/scala/reflect/internal/StdNames.scala
+++ b/src/reflect/scala/reflect/internal/StdNames.scala
@@ -327,6 +327,7 @@ trait StdNames {
     val QUASIQUOTE_FILE: String            = "<quasiquote>"
     val QUASIQUOTE_TUPLE: NameType         = "$quasiquote$tuple$"
     val QUASIQUOTE_CASE: NameType          = "$quasiquote$case$"
+    val QUASIQUOTE_FOR_ENUM: NameType      = "$quasiquote$for$enum$"
     val MIXIN_CONSTRUCTOR: NameType        = "$init$"
     val MODULE_INSTANCE_FIELD: NameType    = NameTransformer.MODULE_INSTANCE_NAME  // "MODULE$"
     val OUTER: NameType                    = "$outer"
@@ -592,6 +593,9 @@ trait StdNames {
     val SyntacticBlock: NameType       = "SyntacticBlock"
     val SyntacticClassDef: NameType    = "SyntacticClassDef"
     val SyntacticDefDef: NameType      = "SyntacticDefDef"
+    val SyntacticFilter: NameType      = "SyntacticFilter"
+    val SyntacticFor: NameType         = "SyntacticFor"
+    val SyntacticForYield: NameType    = "SyntacticForYield"
     val SyntacticFunction: NameType    = "SyntacticFunction"
     val SyntacticFunctionType: NameType = "SyntacticFunctionType"
     val SyntacticPackageObjectDef: NameType = "SyntacticPackageObjectDef"
@@ -602,6 +606,8 @@ trait StdNames {
     val SyntacticTupleType: NameType   = "SyntacticTupleType"
     val SyntacticTypeApplied: NameType = "SyntacticTypeApplied"
     val SyntacticValDef: NameType      = "SyntacticValDef"
+    val SyntacticValEq: NameType       = "SyntacticValEq"
+    val SyntacticValFrom: NameType     = "SyntacticValFrom"
     val SyntacticVarDef: NameType      = "SyntacticVarDef"
     val This: NameType                 = "This"
     val ThisType: NameType             = "ThisType"
@@ -745,7 +751,6 @@ trait StdNames {
     val typedProductIterator: NameType = "typedProductIterator"
     val TypeName: NameType             = "TypeName"
     val typeTagToManifest: NameType    = "typeTagToManifest"
-
     val unapply: NameType              = "unapply"
     val unapplySeq: NameType           = "unapplySeq"
     val unbox: NameType                = "unbox"
@@ -764,6 +769,7 @@ trait StdNames {
     val tq: NameType                   = "tq"
     val cq: NameType                   = "cq"
     val pq: NameType                   = "pq"
+    val fq: NameType                   = "fq"
 
     // unencoded operators
     object raw {