publish initial switch examples

examples.txt

@@ -5,7 +5,7 @@ Hello World
 # Constants
 # For
 If/Else
-# Switch
+Switch
 Arrays
 Slices
 Maps

examples/switch/switch.go

@@ -1,30 +1,45 @@
-// Switch statements allow...
+// _Switch statements_ express conditionals across many
+// branches.
 
 package main
 
 import "fmt"
+import "time"
 
 func main() {
-    fmt.Print("Write 3 as ")
-    i := 3
-    // Some basic commentary on switches.
+
+    // Here's a basic `switch`.
+    i := 2
+    fmt.Print("Write ", i, " as ")
     switch i {
-    case 0:
-        fmt.Println("zero")
     case 1:
         fmt.Println("one")
     case 2:
         fmt.Println("two")
     case 3:
         fmt.Println("three")
-    case 4:
-        fmt.Println("four")
-    case 5:
-        fmt.Println("five")
-    // The `default` branch is optional in a `switch`.
+    }
+
+    // You can use commas to separate multiple expressions
+    // in the same `case` statement. We use the optional
+    // `default` case in this example as well.
+    switch time.Now().Weekday().String() {
+    case "Saturday", "Sunday":
+        fmt.Println("It's the weekend")
     default:
-        fmt.Println("???")
+        fmt.Println("It's a weekday")
+    }
+
+    // `switch` without an expression is an alternate way
+    // to express if/else logic. Here we also show how the
+    // `case` expressions can be non-constants.
+    t := time.Now()
+    switch {
+    case t.Hour() < 12:
+        fmt.Println("It's before noon")
+    default:
+        fmt.Println("It's after noon")
     }
 }
 
-// todo: more complex / non-constant switch?
+// todo: type switches

examples/switch/switch.sh

@@ -1,2 +1,5 @@
 $ go run switch.go 
 Write 3 as three
+It's the weekend
+It's before noon
+