view: add ssize query

view.hpp

@@ -276,6 +276,16 @@ namespace cruft {
             return static_cast<size_type> (std::distance (m_begin, m_end));
         }
 
+
+        ///--------------------------------------------------------------------
+        /// Returns a signed count of items in the view.
+        constexpr ssize_t
+        ssize (void) const noexcept
+        {
+            return std::distance (m_begin, m_end);
+        }
+
+
         ///--------------------------------------------------------------------
         /// Returns a subview of the first `count` elements of this view.
         [[nodiscard]] constexpr auto