Add SummaryConfig::operator[](const std::size_t index)

opm/parser/eclipse/EclipseState/SummaryConfig/SummaryConfig.hpp

@@ -212,6 +212,9 @@ namespace Opm {
                 return runSummaryConfig.create;
             }
 
+            const SummaryConfigNode& operator[](std::size_t index) const;
+
+
         private:
             SummaryConfig( const Deck& deck,
                            const Schedule& schedule,

src/opm/parser/eclipse/EclipseState/SummaryConfig/SummaryConfig.cpp

@@ -1327,6 +1327,10 @@ bool SummaryConfig::hasSummaryKey(const std::string& keyword ) const {
     return summary_keywords.find(keyword) != summary_keywords.end();
 }
 
+const SummaryConfigNode& SummaryConfig::operator[](std::size_t index) const {
+    return this->m_keywords[index];
+}
+
 
 bool SummaryConfig::match(const std::string& keywordPattern) const {
     int flags = 0;