From 06592cedc33db16dac6412b93242c72a756b61ab Mon Sep 17 00:00:00 2001
From: artemp <artem@mapnik.org>
Date: Fri, 29 Nov 2013 13:51:50 +0000
Subject: [PATCH] re-use evaluator object

---
 include/mapnik/expression_evaluator.hpp | 21 +++++++++++----------
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/include/mapnik/expression_evaluator.hpp b/include/mapnik/expression_evaluator.hpp
index f6c4334da..7da728301 100644
--- a/include/mapnik/expression_evaluator.hpp
+++ b/include/mapnik/expression_evaluator.hpp
@@ -38,6 +38,7 @@
 
 namespace mapnik
 {
+
 template <typename T0, typename T1>
 struct evaluate : boost::static_visitor<T1>
 {
@@ -79,7 +80,7 @@ struct evaluate : boost::static_visitor<T1>
 
     value_type operator() (global_attribute const& attr) const
     {
-        return value_type();// shouldn't get here ?  //attr.value<value_type,feature_type>(feature_);
+        return value_type();// shouldn't get here
     }
 
     value_type operator() (geometry_type_attribute const& geom) const
@@ -89,22 +90,22 @@ struct evaluate : boost::static_visitor<T1>
 
     value_type operator() (binary_node<tags::logical_and> const & x) const
     {
-        return (boost::apply_visitor(evaluate<feature_type,value_type>(feature_),x.left).to_bool())
-            && (boost::apply_visitor(evaluate<feature_type,value_type>(feature_),x.right).to_bool());
+        return (boost::apply_visitor(*this, x.left).to_bool())
+            && (boost::apply_visitor(*this, x.right).to_bool());
     }
 
     value_type operator() (binary_node<tags::logical_or> const & x) const
     {
-        return (boost::apply_visitor(evaluate<feature_type,value_type>(feature_),x.left).to_bool())
-            || (boost::apply_visitor(evaluate<feature_type,value_type>(feature_),x.right).to_bool());
+        return (boost::apply_visitor(*this,x.left).to_bool())
+            || (boost::apply_visitor(*this,x.right).to_bool());
     }
 
     template <typename Tag>
     value_type operator() (binary_node<Tag> const& x) const
     {
         typename make_op<Tag>::type operation;
-        return operation(boost::apply_visitor(evaluate<feature_type,value_type>(feature_),x.left),
-                         boost::apply_visitor(evaluate<feature_type,value_type>(feature_),x.right));
+        return operation(boost::apply_visitor(*this, x.left),
+                         boost::apply_visitor(*this, x.right));
     }
 
     template <typename Tag>
@@ -116,12 +117,12 @@ struct evaluate : boost::static_visitor<T1>
 
     value_type operator() (unary_node<tags::logical_not> const& x) const
     {
-        return ! (boost::apply_visitor(evaluate<feature_type,value_type>(feature_),x.expr).to_bool());
+        return ! (boost::apply_visitor(*this,x.expr).to_bool());
     }
 
     value_type operator() (regex_match_node const& x) const
     {
-        value_type v = boost::apply_visitor(evaluate<feature_type,value_type>(feature_),x.expr);
+        value_type v = boost::apply_visitor(*this, x.expr);
 #if defined(BOOST_REGEX_HAS_ICU)
         return boost::u32regex_match(v.to_unicode(),x.pattern);
 #else
@@ -132,7 +133,7 @@ struct evaluate : boost::static_visitor<T1>
 
     value_type operator() (regex_replace_node const& x) const
     {
-        value_type v = boost::apply_visitor(evaluate<feature_type,value_type>(feature_),x.expr);
+        value_type v = boost::apply_visitor(*this, x.expr);
 #if defined(BOOST_REGEX_HAS_ICU)
         return boost::u32regex_replace(v.to_unicode(),x.pattern,x.format);
 #else