expose the kind of json values to simplify the retrieval Python-side

phlex/configuration.hpp

@@ -4,6 +4,7 @@
 #include "boost/json.hpp"
 
 #include <optional>
+#include <utility>
 
 namespace phlex::experimental {
   class configuration {
@@ -32,6 +33,25 @@
       return get_if_present<T>(key).value_or(std::forward<T>(default_value));
     }
 
+    // Internal function for prototype purposes; do not use as this will change.
+    std::pair<boost::json::kind, bool> kind(std::string const& key) const
+    {
+      auto const& value = config_.at(key); // may throw
+
+      auto k = value.kind();
+      bool is_array = k == boost::json::kind::array;
+
+      if (is_array) {
+        // The current configuration interface only supports homogenous containers,
+        // thus checking only the first element suffices. (This assumes arrays are
+        // not nested, which is fine for now.)
+        boost::json::array const& arr = value.as_array();
+        k = arr.empty() ? boost::json::kind::null : arr[0].kind();
+      }
+
+      return std::make_pair(k, is_array);
+    }
+
   private:
     boost::json::object config_;
   };

test/python/driver.cpp

@@ -6,9 +6,10 @@
 namespace {
   class number_generator {
   public:
-    number_generator(phlex::experimental::configuration const& config) :
-      n_{config.get<int>("max_numbers")}
+    number_generator(phlex::experimental::configuration const& config) n_{0}
     {
+      if (config.kind("max_numbers") == boost::json::kind::int64_t)
+        n_ = config.get<int>("max_numbers";
     }
 
     void next(phlex::experimental::framework_driver& driver) const