lean into examples

examples/varadic-functions/varadic-functions.go

@@ -0,0 +1,31 @@
+// Varadic functions can be called with any number of
+// trailing arguments. This is useful if you don't know
+// number of arguments that will be needed for a function
+// ahead of time.
+
+package main
+
+import "fmt"
+
+// Varadic args are declared with `...type` and
+// passed in as a slice.
+func add(nums ...int) int {
+    fmt.Print(nums, " ")
+    total := 0
+    for _, num := range nums {
+        total += num
+    }
+    return total
+}
+
+func main() {
+    // Varadic functions can be called in the usual way.
+    fmt.Println(add(1, 2))
+    fmt.Println(add(1, 2, 3))
+
+    // If you already have multiple args in a slice,
+    // apply them to a varadic function using `
+    // func(slice...)`.                              
+    nums := []int{1, 2, 3, 4}
+    fmt.Println(add(nums...))
+}

examples/varadic-functions/varadic-functions.sh

@@ -0,0 +1,4 @@
+$ go run varadic-functions.go
+[1 2] 3
+[1 2 3] 6
+[1 2 3 4] 10