Merge branch 'master' into master

README.md

@@ -670,7 +670,7 @@ func main() {
 ```
 
 Note that default values set from file (e.g. `FilePath`) take precedence over
-default values set from the enviornment (e.g. `EnvVar`).
+default values set from the environment (e.g. `EnvVar`).
 
 #### Values from alternate input sources (YAML, TOML, and others)
 

app.go

@@ -495,11 +495,12 @@ func (a Author) String() string {
 // it's an ActionFunc or a func with the legacy signature for Action, the func
 // is run!
 func HandleAction(action interface{}, context *Context) (err error) {
-	if a, ok := action.(ActionFunc); ok {
+	switch a := action.(type) {
+	case ActionFunc:
 		return a(context)
-	} else if a, ok := action.(func(*Context) error); ok {
+	case func(*Context) error:
 		return a(context)
-	} else if a, ok := action.(func(*Context)); ok { // deprecated function signature
+	case func(*Context): // deprecated function signature
 		a(context)
 		return nil
 	}