interfaces

about_interfaces.go

@@ -0,0 +1,28 @@
+package go_koans
+
+func testInterfaces() {
+  mspaint := &program{3} // mspaint is a kind of *program, which is a valid 'runner'
+  runOnce(mspaint) // runOnce takes an abstract 'runner' type
+
+  assert(mspaint.runTimes == __int__) // conformed interfaces need not be declared, they are inferred
+}
+
+// abstract interface and function that requires it
+
+type runner interface {
+  run()
+}
+
+func runOnce(r runner) {
+  r.run()
+}
+
+// concrete type implementing the interface
+
+type program struct {
+  runTimes int
+}
+
+func (self *program) run() {
+  self.runTimes++
+}

setup_koans_test.go

@@ -25,10 +25,10 @@ func TestKoans(t *testing.T) {
   //testEnumeration()
   //testAnonymousFunctions()
   //testVariadicFunctions()
-  testFiles()
+  //testFiles()
+  testInterfaces()
 
   // TODO: ie, gameplan
-  //testInterfaces()
   //testMaps()
   //testStructs()
   //testAllocation()