range over channels.

also fix multiple-evaluation bug in range over arrays.

R=ken
OCL=26576
CL=26576

1 files changed, 59 insertions, 0 deletions

diff --git a/test/range.go b/test/range.go
new file mode 100644
index 000000000..7a8c68635
--- /dev/null
+++ b/test/range.go
@@ -0,0 +1,59 @@
+// $G $D/$F.go && $L $F.$A && ./$A.out
+
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+// test range over channels
+
+func gen(c chan int, lo, hi int) {
+	for i := lo; i <= hi; i++ {
+		c <- i;
+	}
+	close(c);
+}
+
+func seq(lo, hi int) chan int {
+	c := make(chan int);
+	go gen(c, lo, hi);
+	return c;
+}
+
+func testchan() {
+	s := "";
+	for i := range seq('a', 'z') {
+		s += string(i);
+	}
+	if s != "abcdefghijklmnopqrstuvwxyz" {
+		panicln("Wanted lowercase alphabet; got", s);
+	}
+}
+
+// test that range over array only evaluates
+// the expression after "range" once.
+
+var nmake = 0;
+func makearray() []int {
+	nmake++;
+	return []int{1,2,3,4,5};
+}
+
+func testarray() {
+	s := 0;
+	for k, v := range makearray() {
+		s += v;
+	}
+	if nmake != 1 {
+		panicln("range called makearray", nmake, "times");
+	}
+	if s != 15 {
+		panicln("wrong sum ranging over makearray");
+	}
+}
+
+func main() {
+	testchan();
+	testarray();
+}