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authorGilles Dubochet <gilles.dubochet@epfl.ch>2005-12-16 18:29:42 +0000
committerGilles Dubochet <gilles.dubochet@epfl.ch>2005-12-16 18:29:42 +0000
commitdf50e05006b43b007c2587549030d24b5c154398 (patch)
tree9edfb1fb5b8c04350a00c163cfcdb1fccd79e3aa /test/files/pos/expressions-current.scala
parent17e2b1c2a6f69ba74e79c30d1e44195fe732e3e3 (diff)
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'test-nsc' has been moved to 'test'.
Diffstat (limited to 'test/files/pos/expressions-current.scala')
-rw-r--r--test/files/pos/expressions-current.scala63
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 });
+ }
+}