Update constructor for wasm interpreter

Author: anutosh491

include/xeus-cpp/xinterpreter_wasm.hpp

@@ -19,8 +19,7 @@ namespace xcpp
     {
     public:
 
-        wasm_interpreter();
-        wasm_interpreter(int argc, char** argv);
+        wasm_interpreter(int argc = 0, char** argv = nullptr);
         virtual ~wasm_interpreter() = default;
 
     };

src/main_emscripten_kernel.cpp

@@ -15,9 +15,26 @@
 
 #include "xeus-cpp/xinterpreter_wasm.hpp"
 
+template <class interpreter_type>
+static interpreter_type* builder_with_args(emscripten::val js_args)
+{
+    static std::vector<std::string> args = emscripten::vecFromJSArray<std::string>(js_args);
+    static std::vector<const char*> argv_vec;
+
+    for (const auto& s : args)
+    {
+        argv_vec.push_back(s.c_str());
+    }
+
+    int argc = static_cast<int>(argv_vec.size());
+    char** argv = const_cast<char**>(argv_vec.data());
+
+    return new interpreter_type(argc, argv);
+}
+
 EMSCRIPTEN_BINDINGS(my_module)
 {
     xeus::export_core();
     using interpreter_type = xcpp::wasm_interpreter;
-    xeus::export_kernel<interpreter_type>("xkernel");
+    xeus::export_kernel<interpreter_type, &builder_with_args<interpreter_type>>("xkernel");
 }

src/xinterpreter_wasm.cpp

@@ -15,12 +15,6 @@
 
 namespace xcpp
 {
-
-    wasm_interpreter::wasm_interpreter()
-        : interpreter(0, nullptr)
-    {
-    }
-
     wasm_interpreter::wasm_interpreter(int argc, char** argv)
         : interpreter(argc, argv)
     {