easy docs

001-hello-world.go

@@ -6,7 +6,7 @@ func main() {
     fmt.Println("Hello world")  // It prints `Hello world`.
 }
 
-/*                              // Put this code in hello-world.go, then use
+/* 
-$ go run hello-world.go         // `go run` to run it.
+$ go run hello-world.go         // Put this code in hello-world.go,
-Hello world
+Hello world                     // then use `go run` to run it.
 */

004-mutation.go

@@ -6,6 +6,12 @@ func main() {
     var x string
     x = "first"
     fmt.Println(x)
-    x = "second"
+    x = "second"    // You can mutate variables in Go.
     fmt.Println(x)
 }
+
+/*
+$ go run mutation.go
+first
+second
+*/

005-literal.go

@@ -3,6 +3,14 @@ package main
 import "fmt"
 
 func main() {
-	x := "Hello World"
+	x := "Hello literal"  // `x := val` is shorthand for `var x type = val`.
 	fmt.Println(x)
 }
+
+/*
+$ go run literal.go
+Hello literal
+*/
+
+// == todo
+// literal?