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author | Paul Phillips <paulp@improving.org> | 2012-01-19 22:08:11 -0800 |
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committer | Paul Phillips <paulp@improving.org> | 2012-01-19 22:08:11 -0800 |
commit | 7a7e049c205a0dda6666f158b1b37558bf214e90 (patch) | |
tree | eab288d9916db45832b66de1e15a1fe774f316ce /test/files/run/macro-range/macro_range_2.scala | |
parent | 14ef1090325c3b85aa8c2dd7911445ec7e934743 (diff) | |
parent | 35e676ded0f9bfd006a5f090841abdea3ff1759c (diff) | |
download | scala-7a7e049c205a0dda6666f158b1b37558bf214e90.tar.gz scala-7a7e049c205a0dda6666f158b1b37558bf214e90.tar.bz2 scala-7a7e049c205a0dda6666f158b1b37558bf214e90.zip |
Merge remote-tracking branch 'kepler/topic/macros' into develop
Diffstat (limited to 'test/files/run/macro-range/macro_range_2.scala')
-rw-r--r-- | test/files/run/macro-range/macro_range_2.scala | 94 |
1 files changed, 94 insertions, 0 deletions
diff --git a/test/files/run/macro-range/macro_range_2.scala b/test/files/run/macro-range/macro_range_2.scala new file mode 100644 index 0000000000..15a018fcff --- /dev/null +++ b/test/files/run/macro-range/macro_range_2.scala @@ -0,0 +1,94 @@ +import reflect.api.Modifier +import reflect.macro.Context + +abstract class RangeDefault { + val from, to: Int + def foreach(f: Int => Unit) = { + var i = from + while (i < to) { f(i); i += 1 } + } +} + +/** This class should go into reflect.macro once it is a bit more stable. */ +abstract class Utils { + val context: Context + import context._ + + class TreeSubstituter(from: List[Symbol], to: List[Tree]) extends Transformer { + override def transform(tree: Tree): Tree = tree match { + case Ident(_) => + def subst(from: List[Symbol], to: List[Tree]): Tree = + if (from.isEmpty) tree + else if (tree.symbol == from.head) to.head.duplicate // TODO: does it ever make sense *not* to perform a shallowDuplicate on `to.head`? + else subst(from.tail, to.tail); + subst(from, to) + case _ => + val tree1 = super.transform(tree) + if (tree1 ne tree) tree1.tpe = null + tree1 + } + } + def makeApply(fn: Tree, args: List[Tree]): Tree = fn match { + case Function(vparams, body) => + new TreeSubstituter(vparams map (_.symbol), args) transform body + case Block(stats, expr) => + Block(stats, makeApply(expr, args)) + case _ => + println("no beta on "+fn+" "+fn.getClass) + Apply(fn, args) + } + def makeWhile(lname: TermName, cond: Tree, body: Tree): Tree = { + val continu = Apply(Ident(lname), Nil) + val rhs = If(cond, Block(List(body), continu), Literal(Constant())) + LabelDef(lname, Nil, rhs) + } + def makeBinop(left: Tree, op: String, right: Tree): Tree = + Apply(Select(left, newTermName(op)), List(right)) +} + +class Range(val from: Int, val to: Int) extends RangeDefault { + override def macro foreach(f: Int => Unit): Unit = { + println("macro-expand, _this = "+ _this) + import _context._ + object utils extends Utils { + val context: _context.type = _context + } + import utils._ + + val initName = newTermName("<init>") + // Either: + // scala"{ var i = $low; val h = $hi; while (i < h) { $f(i); i = i + 1 } } + // or: + // scala"($_this: RangeDefault).foreach($f)" + _this match { + case Apply(Select(New(tpt), initName), List(lo, hi)) if tpt.symbol.fullName == "Range" => + val iname = newTermName("$i") + val hname = newTermName("$h") + def iref = Ident(iname) + def href = Ident(hname) + val labelname = newTermName("$while") + val cond = makeBinop(iref, "$less", href) + val body = Block( + List(makeApply(f, List(iref))), + Assign(iref, makeBinop(iref, "$plus", Literal(Constant(1))))) + tools.nsc.util.trace("generated: ")( + Block( + List( + ValDef(Modifiers(Set(Modifier.mutable)), iname, TypeTree(), lo), + ValDef(Modifiers(), hname, TypeTree(), hi)), + makeWhile(labelname, cond, body))) + case _ => + Apply( + Select( + Typed(_this, Ident(newTypeName("RangeDefault"))), + newTermName("foreach")), + List(f)) + } + } +} + +object Test extends App { + + new Range(1, 10) foreach println + +} |