Data commit

Task/Scope-Function-names-and-labels/Go/scope-function-names-and-labels-1.go

@@ -0,0 +1,24 @@
+package main
+
+import (
+    "fmt"
+    "runtime"
+
+    "ex"
+)
+
+func main() {
+    // func nested() { ... not allowed here
+
+    // this is okay, variable f declared and assigned a function literal.
+    f := func() {
+        // this mess prints the name of the function to show that it's an
+        // anonymous function defined in package main
+        pc, _, _, _ := runtime.Caller(0)
+        fmt.Println(runtime.FuncForPC(pc).Name(), "here!")
+    }
+
+    ex.X(f) // function value passed to exported function
+
+    // ex.x() non-exported function not visible here
+}

Task/Scope-Function-names-and-labels/Go/scope-function-names-and-labels-2.go

@@ -0,0 +1,17 @@
+package ex
+
+import (
+    "fmt"
+    "runtime"
+)
+
+// X is exported.
+func X(x func()) {
+    pc, _, _, _ := runtime.Caller(0)
+    fmt.Println(runtime.FuncForPC(pc).Name(), "calling argument x...")
+    x()
+}
+
+func x() { // not exported, x not upper case.
+    panic("top level x")
+}

Task/Scope-Function-names-and-labels/Go/scope-function-names-and-labels-3.go

@@ -0,0 +1,29 @@
+package main
+
+import "fmt"
+
+func main() {
+    // labels loop and y both in scope of main
+loop:
+    for false {
+        continue loop
+    }
+    goto y
+y:
+    y := 0 // variable namespace is separate from label namespace
+
+    func() {
+        // goto loop ...loop not visible from this literal
+
+        // label y in outer scope not visible so it's okay to define a label y
+        // here too.
+    y:
+        for {
+            break y
+        }
+        y++ // regular lexical scoping applies to variables.
+    }()
+    fmt.Println(y)
+}
+
+// end: // labels not allowed outside function blocks