Added support for std::pair in the JSON serialiser

lib/serialisation/JSON_IO.cc

@@ -42,7 +42,7 @@ JSONWriter::~JSONWriter(void)
 
   // write prettified JSON to file
   std::ofstream os(fileName_);
-  std::cout << "JSONWriter::~JSONWriter" << std::endl;
+  //std::cout << "JSONWriter::~JSONWriter" << std::endl;
   os << std::setw(2) << json::parse(ss_.str()) << std::endl;
 }
 
@@ -57,7 +57,7 @@ void JSONWriter::push(const string &s)
 
 void JSONWriter::pop(void)
 {
-  std::cout << "JSONWriter::pop" << std::endl;
+  //std::cout << "JSONWriter::pop" << std::endl;
   delete_comma();
   ss_ << "},";
 }
@@ -69,6 +69,7 @@ void JSONWriter::delete_comma()
   ss_.str(dlast);
 }
 
+/*
 // here we are hitting a g++ bug (Bug 56480)
 // compiles fine with clang
 // have to wrap in the Grid namespace
@@ -76,8 +77,7 @@ void JSONWriter::delete_comma()
 namespace Grid
 {
   template<>
-  void JSONWriter::writeDefault(const std::string &s,
+  void JSONWriter::writeDefault(const std::string &s,	const std::string &x)
-				const std::string &x)
   {
     if (s.size())
       ss_ << "\""<< s << "\" : \"" << x << "\" ," ; 
@@ -85,7 +85,7 @@ namespace Grid
       ss_ << "\"" << x << "\" ," ;
   }
 }// namespace Grid 
-
+*/
 
 // Reader implementation ///////////////////////////////////////////////////////
 JSONReader::JSONReader(const string &fileName)
@@ -140,6 +140,7 @@ void JSONReader::pop(void)
 
 bool JSONReader::nextElement(const std::string &s)
 {
+  // Work in progress
   // JSON dictionaries do not support multiple names 
   // Same name objects must be packed in vectors
   ++it_;

lib/serialisation/JSON_IO.h

@@ -58,10 +58,13 @@ namespace Grid
     void writeDefault(const std::string &s, const std::complex<U> &x);
     template <typename U>
     void writeDefault(const std::string &s, const std::vector<U> &x);
+    template <typename U, typename P>
+    void writeDefault(const std::string &s, const std::pair<U,P> &x);
 
     template<std::size_t N>
     void writeDefault(const std::string &s, const char(&x)[N]);
 
+
   private:
     void delete_comma();
     std::string         fileName_;
@@ -82,6 +85,8 @@ namespace Grid
     void readDefault(const std::string &s, std::complex<U> &output);
     template <typename U>
     void readDefault(const std::string &s, std::vector<U> &output);
+    template <typename U, typename P>
+    void readDefault(const std::string &s, std::pair<U,P> &output);
   private:
     json                jobject_; // main object
     json                jcur_;  // current json object
@@ -106,7 +111,7 @@ namespace Grid
   template <typename U>
   void JSONWriter::writeDefault(const std::string &s, const U &x)
   {
-    //std::cout << "JSONWriter::writeDefault(U) : " << s <<  std::endl;
+    //std::cout << "JSONWriter::writeDefault(U) : " << s <<  " " << x <<std::endl;
     std::ostringstream os;
     os << std::boolalpha << x;
     if (s.size())
@@ -119,7 +124,7 @@ namespace Grid
   template <>
   void JSONWriter::writeDefault(const std::string &s, const std::string &x)
   {
-    //std::cout << "JSONWriter::writeDefault(U) : " << s <<  std::endl;
+    //std::cout << "JSONWriter::writeDefault(string) : " << s <<  std::endl;
     std::ostringstream os;
     os << std::boolalpha << x;
     if (s.size())
@@ -142,6 +147,18 @@ namespace Grid
      ss_ << os.str() << " ," ;
   }
 
+  template <typename U, typename P>
+  void JSONWriter::writeDefault(const std::string &s, const std::pair<U,P> &x)
+  {
+    //std::cout << "JSONWriter::writeDefault(pair) : " << s <<  " " << x <<  std::endl;
+    std::ostringstream os;
+    os << "["<< std::boolalpha << "\""<< x.first << "\" , \"" << x.second << "\" ]";
+    if (s.size())
+      ss_ << "\""<< s << "\" : " << os.str() << " ," ;
+    else
+     ss_ << os.str() << " ," ;
+  }
+
   template <typename U>
   void JSONWriter::writeDefault(const std::string &s, const std::vector<U> &x)
   {
@@ -188,6 +205,30 @@ namespace Grid
 
   }
 
+  // Reader template implementation ////////////////////////////////////////////
+  template <typename U, typename P>
+  void JSONReader::readDefault(const std::string &s, std::pair<U,P> &output)
+  {
+    U first;
+    P second;
+    json j;
+    if (s.size()){
+      //std::cout << "JSONReader::readDefault(pair) : " << s << "  |  "<< jcur_[s] << std::endl;
+      j = jcur_[s];
+    } else {
+      j = jcur_;
+    }
+    json::iterator it = j.begin();
+    jcur_ = *it;
+    read("", first);
+    it++;
+    jcur_ = *it;
+    read("", second);
+    output = std::pair<U,P>(first,second);
+  }
+
+
+
   template <typename U>
   void JSONReader::readDefault(const std::string &s, std::complex<U> &output)
   {

tests/IO/Test_serialisation.cc

@@ -29,7 +29,6 @@ Author: Peter Boyle <paboyle@ph.ed.ac.uk>
     /*  END LEGAL */
 #include <Grid/Grid.h>
 
-
 using namespace Grid;
 using namespace Grid::QCD;
 
@@ -152,9 +151,9 @@ int main(int argc,char **argv)
   ioTest<TextWriter, TextReader>("iotest.dat", vec, "text   (vector of objects)");
   ioTest<TextWriter, TextReader>("iotest.dat", pair, "text   (pair of objects)");
   //// text
-  ioTest<JSONWriter, JSONReader>("iotest.json", obj, "JSON   (object)           ");
+  ioTest<JSONWriter, JSONReader>("iotest.json", obj,  "JSON   (object)           ");
-  ioTest<JSONWriter, JSONReader>("iotest.json", vec, "JSON   (vector of objects)");
+  ioTest<JSONWriter, JSONReader>("iotest.json", vec,  "JSON   (vector of objects)");
-  //ioTest<JSONWriter, JSONReader>("iotest.json", pair, "JSON   (pair of objects)");
+  ioTest<JSONWriter, JSONReader>("iotest.json", pair, "JSON   (pair of objects)");
 
   //// HDF5
 #undef HAVE_HDF5