add logging test

Author: odersky

tests/pos/inline-logging.scala

@@ -0,0 +1,30 @@
+object Config {
+  inline val logging = true
+}
+
+object Logger {
+
+  private var indent = 0
+
+  inline def log[T](msg: => String, indentMargin: Int)(op: => T): T =
+    if (Config.logging) {
+      val msgVal = msg
+      println(s"${"  " * indent}start $msgVal")
+      indent += indentMargin
+      val result = op
+      indent -= indentMargin
+      println(s"${"  " * indent}$msgVal = $result")
+      result
+    }
+    else op
+}
+import Logger._
+
+var indentSetting = 2
+
+def factorial(n: BigInt): BigInt = {
+  log(s"factorial($n)", indentSetting) {
+    if (n == 0) 1
+    else n * factorial(n - 1)
+  }
+}