Full support of the http.FileSystem on all view engines as requested at #1575

Also, the HandleDir accepts both string and http.FileSystem (interface{}) (like the view's fs)

_examples/view/template_pug_0/main.go

@@ -1,16 +1,24 @@
+// Package main shows an example of pug actions based on https://github.com/Joker/jade/tree/master/example/actions
 package main
 
 import "github.com/kataras/iris/v12"
 
+type Person struct {
+	Name   string
+	Age    int
+	Emails []string
+	Jobs   []*Job
+}
+
+type Job struct {
+	Employer string
+	Role     string
+}
+
 func main() {
 	app := iris.New()
 
 	tmpl := iris.Pug("./templates", ".pug")
-	tmpl.Reload(true)                             // reload templates on each request (development mode)
-	tmpl.AddFunc("greet", func(s string) string { // add your template func here.
-		return "Greetings " + s + "!"
-	})
-
 	app.RegisterView(tmpl)
 
 	app.Get("/", index)
@@ -20,9 +28,15 @@ func main() {
 }
 
 func index(ctx iris.Context) {
-	ctx.ViewData("pageTitle", "My Index Page")
-	ctx.ViewData("youAreUsingJade", true)
-	// Q: why need extension .pug?
-	// A: Because you can register more than one view engine per Iris application.
-	ctx.View("index.pug")
+	job1 := Job{Employer: "Monash B", Role: "Honorary"}
+	job2 := Job{Employer: "Box Hill", Role: "Head of HE"}
+
+	person := Person{
+		Name:   "jan",
+		Age:    50,
+		Emails: []string{"jan@newmarch.name", "jan.newmarch@gmail.com"},
+		Jobs:   []*Job{&job1, &job2},
+	}
+
+	ctx.View("index.pug", person)
 }

_examples/view/template_pug_0/templates/index.pug

@@ -1,25 +1,20 @@
-mixin withGo
-  | Generating Go html/template output.
-
 doctype html
 html(lang="en")
-  head
-    title= .pageTitle
-    script(type='text/javascript').
-      if (foo) {
-         bar(1 + 5)
-      }
-  body
-    h1 Jade - template engine
-    #container.col
-      if .youAreUsingJade
-        p {{ greet "iris user" }} <!-- execute template funcs -->
-        p You are amazing!
-      else
-        p Get on it!
-      p.
-        Jade is #[a(terse)] and simple
-        templating language with a
-        #[strong focus] on performance
-        and powerful features.
-      + withGo
+	head
+		meta(charset="utf-8")
+		title Title
+	body
+		p ads
+		ul
+			li The name is {{.Name}}.
+			li The age is {{.Age}}.
+
+		each _,_ in .Emails
+			div An email is {{.}}
+
+		| {{ with .Jobs }}
+			each _,_ in .
+				div
+				 An employer is {{.Employer}}
+				 and the role is {{.Role}}
+		| {{ end }}