Add text and html/template Option func to the view engine as requested https://github.com/kataras/iris/issues/694

Former-commit-id: 4633a62addf6a25ee99d1e7f4c00f6e3555cee76

view/html.go

@@ -22,6 +22,7 @@ type (
 		namesFn   func() []string                   // for embedded, in combination with directory & extension
 		reload    bool                              // if true, each time the ExecuteWriter is called the templates will be reloaded.
 		// parser configuration
+		options     []string // text options
 		left        string
 		right       string
 		layout      string
@@ -98,6 +99,31 @@ func (s *HTMLEngine) Reload(developmentMode bool) *HTMLEngine {
 	return s
 }
 
+// Option sets options for the template. Options are described by
+// strings, either a simple string or "key=value". There can be at
+// most one equals sign in an option string. If the option string
+// is unrecognized or otherwise invalid, Option panics.
+//
+// Known options:
+//
+// missingkey: Control the behavior during execution if a map is
+// indexed with a key that is not present in the map.
+//	"missingkey=default" or "missingkey=invalid"
+//		The default behavior: Do nothing and continue execution.
+//		If printed, the result of the index operation is the string
+//		"<no value>".
+//	"missingkey=zero"
+//		The operation returns the zero value for the map type's element.
+//	"missingkey=error"
+//		Execution stops immediately with an error.
+//
+func (s *HTMLEngine) Option(opt ...string) *HTMLEngine {
+	s.mu.Lock()
+	s.options = append(s.options, opt...)
+	s.mu.Unlock()
+	return s
+}
+
 // Delims sets the action delimiters to the specified strings, to be used in
 // subsequent calls to Parse, ParseFiles, or ParseGlob. Nested template
 // definitions will inherit the settings. An empty delimiter stands for the
@@ -199,7 +225,7 @@ func (s *HTMLEngine) loadDirectory() error {
 
 				name := filepath.ToSlash(rel)
 				tmpl := s.Templates.New(name)
-
+				tmpl.Option(s.options...)
 				if s.middleware != nil {
 					contents, err = s.middleware(name, contents)
 				}
@@ -263,6 +289,7 @@ func (s *HTMLEngine) loadAssets() error {
 			contents := string(buf)
 			name := filepath.ToSlash(rel)
 			tmpl := s.Templates.New(name)
+			tmpl.Option(s.options...)
 
 			if s.middleware != nil {
 				contents, err = s.middleware(name, contents)