feat: init explain subcommand

cmd/explain.go

@@ -0,0 +1,41 @@
+package cmd
+
+import (
+	"fmt"
+	"net"
+	"os"
+
+	"github.com/bschaatsbergen/cidr/pkg/core"
+	"github.com/spf13/cobra"
+)
+
+var (
+	explainCmd = &cobra.Command{
+		Use:   "explain",
+		Short: "Provides information about a CIDR range",
+		Run: func(cmd *cobra.Command, args []string) {
+			if len(args) != 1 {
+				fmt.Println("error: provide a CIDR range and an IP address")
+				fmt.Println("See 'cidr contains -h' for help and examples")
+				os.Exit(1)
+			}
+			network, err := core.ParseCIDR(args[0])
+			if err != nil {
+				fmt.Printf("error: %s\n", err)
+				fmt.Println("See 'cidr contains -h' for help and examples")
+				os.Exit(1)
+			}
+			foo, bar := explain(network)
+			fmt.Println(foo)
+			fmt.Println(bar)
+		},
+	}
+)
+
+func init() {
+	rootCmd.AddCommand(explainCmd)
+}
+
+func explain(network *net.IPNet) (string, string) {
+	return "", ""
+}