From bdf787665263b7af018c837222f19aeaa534903d Mon Sep 17 00:00:00 2001
From: Artem Pavlenko <artem@mapnik.org>
Date: Thu, 19 Jul 2018 15:36:00 +0100
Subject: [PATCH] const-ness

---
 include/mapnik/expression_grammar_x3_def.hpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/mapnik/expression_grammar_x3_def.hpp b/include/mapnik/expression_grammar_x3_def.hpp
index 7f644f4c9..287545483 100644
--- a/include/mapnik/expression_grammar_x3_def.hpp
+++ b/include/mapnik/expression_grammar_x3_def.hpp
@@ -87,7 +87,7 @@ namespace mapnik { namespace grammar {
 
     auto do_attribute = [] (auto const& ctx)
     {
-        auto & attr = _attr(ctx);
+        auto const& attr = _attr(ctx);
         if (attr == "mapnik::geometry_type")
         {
             _val(ctx) = std::move(geometry_type_attribute());
@@ -130,7 +130,7 @@ namespace mapnik { namespace grammar {
 
     auto do_unicode = [] (auto const& ctx)
     {
-        auto & tr = x3::get<transcoder_tag>(ctx).get();
+        auto const& tr = x3::get<transcoder_tag>(ctx).get();
         _val(ctx) = std::move(tr.transcode(_attr(ctx).c_str()));
     };