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author | Gilles Dubochet <gilles.dubochet@epfl.ch> | 2005-12-16 18:29:42 +0000 |
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committer | Gilles Dubochet <gilles.dubochet@epfl.ch> | 2005-12-16 18:29:42 +0000 |
commit | df50e05006b43b007c2587549030d24b5c154398 (patch) | |
tree | 9edfb1fb5b8c04350a00c163cfcdb1fccd79e3aa /test/files/pos/expressions-current.scala | |
parent | 17e2b1c2a6f69ba74e79c30d1e44195fe732e3e3 (diff) | |
download | scala-df50e05006b43b007c2587549030d24b5c154398.tar.gz scala-df50e05006b43b007c2587549030d24b5c154398.tar.bz2 scala-df50e05006b43b007c2587549030d24b5c154398.zip |
'test-nsc' has been moved to 'test'.
Diffstat (limited to 'test/files/pos/expressions-current.scala')
-rw-r--r-- | test/files/pos/expressions-current.scala | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/test/files/pos/expressions-current.scala b/test/files/pos/expressions-current.scala new file mode 100644 index 0000000000..b343dbf68b --- /dev/null +++ b/test/files/pos/expressions-current.scala @@ -0,0 +1,63 @@ +package test; + +abstract class Lang { + trait Visitor { + def caseNum(n: int): unit; + } + + abstract class Exp { + def visit(v: visitor): unit; + } + + type visitor <: Visitor; + + class Num(n: int) extends Exp { + def visit(v: visitor): unit = v.caseNum(n); + } + + class Eval(result: Ref[int]): visitor extends Visitor { + def caseNum(n: int) = result.elem = n; + } +} + +abstract class Lang2 extends Lang { + trait Visitor2 extends Visitor { + def casePlus(left: Exp, right: Exp): unit; + } + + type visitor <: Visitor2; + + class Plus(l: Exp, r: Exp) extends Exp { + def visit(v: visitor): unit = v.casePlus(l, r); + } + + class Eval2(result: Ref[int]): visitor extends Eval(result) with Visitor2 { + def casePlus(l: Exp, r: Exp) = + result.elem = { l.visit(this); result.elem } + { r.visit(this); result.elem } + } + + class Show2(result: Ref[String]): visitor extends Visitor2 { + def caseNum(n: int) = result.elem = n.toString(); + def casePlus(l: Exp, r: Exp) = + result.elem = + "(" + { l.visit(this); result.elem } + + "+" + { r.visit(this); result.elem }+ ")"; + } +} + +object Main { + + def main(args: Array[String]) = { + object l1 extends Lang { type visitor = Visitor } + val e1: l1.Exp = new l1.Num(42); + + val iref = new Ref(0); + System.out.println("eval: " + { e1.visit(new l1.Eval(iref)); iref.elem }); + + object l2 extends Lang2 { type visitor = Visitor2 } + val e2: l2.Exp = new l2.Plus(new l2.Num(5), new l2.Num(37)); + val sref = new Ref(""); + System.out.println("eval: " + { e2.visit(new l2.Eval2(iref)); iref.elem }); + System.out.println("show: " + { e2.visit(new l2.Show2(sref)); sref.elem }); + } +} |