new member function children()

include/seqan3/index/fm_index_iterator.hpp

@@ -121,7 +121,7 @@ class fm_index_iterator
         {
             ++c;
         }
-        
+
         if (c != index->m_index.sigma)
         {
             parent_lb = node.lb;
@@ -193,7 +193,25 @@ class fm_index_iterator
         return true;
     }
 
-    bool right()
+    auto children() noexcept
+    {
+        // TODO: this will not work since value_size is not defined for char
+        std::array<fm_index_iterator, index_type::char_type::value_size> children;
+
+        // TODO: this will be implemented much more efficiently
+        uint8_t i = 0;
+        if (down())
+        {
+            do
+            {
+                children[i++] = *this;
+            } while (right());
+        }
+
+        return children;
+    }
+
+    bool right() noexcept
     {
         assert(depth() > 0);
         typename index_type::comp_char_type c = node.last_char + 1;