1 files changed, 16 insertions, 2 deletions
diff --git a/absl/random/internal/distribution_caller.h b/absl/random/internal/distribution_caller.h
index ae2680dd..02603cf8 100644
--- a/absl/random/internal/distribution_caller.h
+++ b/absl/random/internal/distribution_caller.h
@@ -31,8 +31,22 @@ namespace random_internal {
 template <typename URBG>
 struct DistributionCaller {
   // Call the provided distribution type. The parameters are expected
-  // to be explicitly specified.  DistrT is the distribution type.
-  template <typename DistrT, typename... Args>
+  // to be explicitly specified.
+  // DistrT is the distribution type.
+  // FormatT is the formatter type:
+  //
+  // struct FormatT {
+  //   using result_type = distribution_t::result_type;
+  //   static std::string FormatCall(
+  //       const distribution_t& distr,
+  //       absl::Span<const result_type>);
+  //
+  //   static std::string FormatExpectation(
+  //       absl::string_view match_args,
+  //       absl::Span<const result_t> results);
+  // }
+  //
+  template <typename DistrT, typename FormatT, typename... Args>
   static typename DistrT::result_type Call(URBG* urbg, Args&&... args) {
     DistrT dist(std::forward<Args>(args)...);
     return dist(*urbg);