Use special character \x1B escape to clear messenger widget

Author: pennam

src/property/Property.cpp

@@ -55,6 +55,14 @@ Property::Property()
 
 }
 
+/******************************************************************************
+   CONST
+ ******************************************************************************/
+namespace PropertyActions
+{
+  const String CLEAR = "\x1B";
+}
+
 /******************************************************************************
    PUBLIC MEMBER FUNCTIONS
  ******************************************************************************/

src/property/Property.h

@@ -51,6 +51,14 @@
 #define appendAttribute(x) appendAttributeReal(x, getAttributeName(#x, '.'), encoder)
 #define setAttribute(x) setAttributeReal(x, getAttributeName(#x, '.'))
 
+/******************************************************************************
+   CONST
+ ******************************************************************************/
+namespace PropertyActions
+{
+  extern const String CLEAR;
+}
+
 /******************************************************************************
    ENUM
  ******************************************************************************/

src/property/types/CloudString.h

@@ -83,6 +83,9 @@ class CloudString : public Property {
     friend CloudString operator+(CloudString cs, String v) {
       return cs += v;
     }
+    void clear() {
+      _value = PropertyActions::CLEAR;
+    }
 };