apps.Switch/Hosts minor doc improvement

Author: kataras

apps/README.md

@@ -121,9 +121,9 @@ Example Code:
 
 ```go
 switcher := Switch(Hosts{
-	"mydomain.com": app,
-	"test.mydomain.com": testSubdomainApp,
-	"otherdomain.com": "appName",
+	{Pattern: "mydomain.com", Target: app},
+	{Pattern: "test.mydomain.com", Target: testSubdomainApp},
+	{Pattern: "otherdomain.com", Target: "appName"},
 })
 switcher.Listen(":80")
 ```
@@ -211,7 +211,7 @@ Switch(Join{
 		App:    myapp,
 	},
 	Hosts{
-		{"^test.*$", myapp},
+		{Pattern: "^test.*$", Target: myapp},
 	},
 })
 ```

apps/switch.go

@@ -15,9 +15,9 @@ import (
 // Example Code:
 //
 //	switcher := Switch(Hosts{
-//		"mydomain.com": app,
-//		"test.mydomain.com": testSubdomainApp,
-//		"otherdomain.com": "appName",
+//		{ Pattern: "mydomain.com", Target: app },
+//		{ Pattern: "test.mydomain.com", Target: testSubdomainApp },
+//		{ Pattern: "otherdomain.com", "Target: appName" },
 //	})
 //	switcher.Listen(":80")
 //
@@ -35,6 +35,28 @@ import (
 //
 // Wrap with the `Join` slice to pass
 // more than one provider at the same time.
+//
+// An alternative way for manually embedding an Iris Application to another one is:
+//
+//	app := iris.New() // root app.
+//	myOtherApp := api.NewServer(otherServerConfiguration) // embedded app.
+//	// myOtherApp.Logger().SetLevel("debug")
+//
+//	if err := myOtherApp.Build(); err != nil {
+//		panic(err)
+//	}
+//
+//	app.Any("/api/identity/{p:path}", func(ctx iris.Context) {
+//		apiPath := "/" + ctx.Params().Get("p")
+//		r := ctx.Request()
+//		r.URL.Path = apiPath
+//		r.URL.RawPath = apiPath
+//		ctx.Params().Remove("p")
+//
+//		myOtherApp.ServeHTTPC(ctx)
+//	})
+//
+// app.Listen(":80")
 func Switch(provider SwitchProvider, options ...SwitchOption) *iris.Application {
 	cases := provider.GetSwitchCases()
 	if len(cases) == 0 {

apps/switch_hosts.go

@@ -36,6 +36,22 @@ type (
 
 var _ SwitchProvider = Hosts{}
 
+// AnyDomain is a regexp that matches any domain.
+// It can be used as the Pattern field of a Host.
+//
+// Example:
+//
+//	apps.Switch(apps.Hosts{
+//		{
+//			Pattern: "^id.*$", Target: identityApp,
+//		},
+//		{
+//			Pattern: apps.AnyDomain, Target: app,
+//		},
+//	}).Listen(":80")
+const AnyDomain = `^(([a-zA-Z]{1})|([a-zA-Z]{1}[a-zA-Z]{1})|([a-zA-Z]{1}[0-9]{1})|([0-9]{1}[a-zA-Z]{1})|([a-zA-Z0-9][a-zA-Z0-9-_]{1,61}[a-zA-Z0-9]))\.([a-zA-Z]{2,6}|[a-zA-Z0-9-]{2,30}\.[a-zA-Z
+	]{2,3})$`
+
 // GetSwitchCases completes the SwitchProvider.
 // It returns a slice of SwitchCase which
 // if passed on `Switch` function, they act