ddl: use witness in C++ fromJSON function

3 files changed, 18 insertions, 15 deletions

diff --git a/lib/RT.cpp b/lib/RT.cpp
index c76c1d1..741596c 100644
--- a/lib/RT.cpp
+++ b/lib/RT.cpp
@@ -20,24 +20,24 @@ template<> json toJSON<unsigned int>(unsigned int &v) {
   return json(v);
 }
 
-template<> String fromJSON<String>(String &v, json &obj) {
+template<> String fromJSON<String>(W<String> v, json &obj) {
   String s;
   return s;
 }
 
-template<> Float fromJSON<Float>(Float &v, json &obj) {
+template<> Float fromJSON<Float>(W<Float> v, json &obj) {
   return 0.0;
 }
 
-template<> bool fromJSON<bool>(bool &v, json &obj) {
+template<> bool fromJSON<bool>(W<bool> v, json &obj) {
   return false;
 }
 
-template<> int fromJSON<int>(int &v, json &obj) {
+template<> int fromJSON<int>(W<int> v, json &obj) {
   return 0;
 }
 
-template<> unsigned int fromJSON<unsigned int>(unsigned int &v, json &obj) {
+template<> unsigned int fromJSON<unsigned int>(W<unsigned int> v, json &obj) {
   return 0;
 }
 
diff --git a/lib/RT.hpp b/lib/RT.hpp
index 569ebf2..d34557e 100644
--- a/lib/RT.hpp
+++ b/lib/RT.hpp
@@ -97,40 +97,43 @@ json toJSON(std::map<k,v> &value) {
 }
 
 template<typename T>
-T fromJSON(T &v, json &obj);
+struct W {};
+
+template<typename T>
+T fromJSON(W<T> w, json &obj);
 
 template<typename any>
-Maybe<any> fromJSON(Maybe<any> &v, json &obj) {
+Maybe<any> fromJSON(W<Maybe<any>> v, json &obj) {
   Maybe<any> a;
   return a;
 }
 
 template<typename any>
-V2<any> fromJSON(V2<any> &v, json &obj) {
+V2<any> fromJSON(W<V2<any>> v, json &obj) {
   V2<any> a;
   return a;
 }
 
 template<typename any>
-V3<any> fromJSON(V3<any> &v, json &obj) {
+V3<any> fromJSON(W<V3<any>> v, json &obj) {
   V3<any> a;
   return a;
 }
 
 template<typename any>
-V4<any> fromJSON(V4<any> &v, json &obj) {
+V4<any> fromJSON(W<V4<any>> v, json &obj) {
   V4<any> a;
   return a;
 }
 
 template<typename any>
-std::vector<any> fromJSON(std::vector<any> &v, json &obj) {
+std::vector<any> fromJSON(W<std::vector<any>> v, json &obj) {
   std::vector<any> a;
   return a;
 }
 
 template<typename k, typename v>
-std::map<k,v> fromJSON(std::map<k,v> &value, json &obj) {
+std::map<k,v> fromJSON(W<std::map<k,v>> value, json &obj) {
   std::map<k,v> a;
   return a;
 }
diff --git a/templates/data.cpp.ede b/templates/data.cpp.ede
index ac6012c..2b3e865 100644
--- a/templates/data.cpp.ede
+++ b/templates/data.cpp.ede
@@ -22,7 +22,7 @@ template<> json toJSON<{{ t.value.dataName }}>({{ t.value.dataName }} &v) {
   return obj;
 }
 
-template<> {{ t.value.dataName }} fromJSON<{{ t.value.dataName }}>({{ t.value.dataName }} &v, json &obj) {
+template<> {{ t.value.dataName }} fromJSON<{{ t.value.dataName }}>(W<{{ t.value.dataName }}> v, json &obj) {
   std::cout << "fromJSON: {{ t.value.dataName }}\n";
   enum ::{{ t.value.dataName }}::tag tagType;
   std::string tag = obj["tag"];
@@ -32,8 +32,8 @@ template<> {{ t.value.dataName }} fromJSON<{{ t.value.dataName }}>({{ t.value.da
     {% if !(c.value.fields | empty) %}
     ::data::{{ c.value.name }} tv;
     tv.tag = tagType;{% for f in c.value.fields %}{% if c.value.fields | hasFieldNames %}
-    tv.{{ f.value.fieldName }} = fromJSON(tv.{{ f.value.fieldName }}, obj["{{ f.value.fieldName }}"]);{% else %}
-    tv._{{ f.index0 }} = fromJSON(tv._{{ f.index0 }}, obj["arg{{ f.index0 }}"]);{% endif %}{% endfor %}
+    tv.{{ f.value.fieldName }} = fromJSON(W<{{ f.value.fieldType | cppType }}>(), obj["{{ f.value.fieldName }}"]);{% else %}
+    tv._{{ f.index0 }} = fromJSON(W<{{ f.value.fieldType | cppType }}>(), obj["arg{{ f.index0 }}"]);{% endif %}{% endfor %}
     return tv;
     {% endif %}
   }