Added Fl_Input_::append() method (STR #2953).

CHANGES.txt

@@ -102,6 +102,7 @@ Changes in FLTK 1.4.0					Released: ??? ?? 2019
   Other Improvements
 
   - (add new items here)
+  - Added Fl_Input_::append() method (STR #2953).
   - Fix for STR#3473 (and its duplicate STR#3507) to restore configure-based
     builds on recent Linux/Unix distributions where the freetype-config
     command has been replaced by pkg-config.

FL/Fl_Input_.H

@@ -359,6 +359,9 @@ public:
   */
   int insert(const char* t, int l=0){return replace(position_, mark_, t, l);}
 
+  /* Append text at the end. */
+  int append(const char* t, int l=0, char keep_selection=0);
+
   /* Put the current selection into the clipboard. */
   int copy(int clipboard);
 

src/Fl_Input_.cxx

@@ -743,6 +743,30 @@ static void undobuffersize(int n) {
   }
 }
 
+/**
+ Append text at the end.
+
+ This function appends the string in \p t to the end of the text.
+ It does not moves the new position or mark.
+
+ \param [in] t text that will be appended
+ \param [in] l length of text, or 0 if the string is terminated by \c nul.
+ \param [in] keep_selection if this is 1, the current text selection will
+    remain, if 0, the cursor will move to the end of the inserted text.
+ \return 0 if no text was appended
+ */
+int Fl_Input_::append(const char* t, int l, char keep_selection)
+{
+  int end = size();
+  int om = mark_, op = position_;
+  int ret = replace(end, end, t, l);
+  if (keep_selection) {
+    position(op, om);
+  }
+  return ret;
+}
+
+
 /**
   Deletes text from \p b to \p e and inserts the new string \p text.