Nim/tests/cpp/tinitializers.nim

discard """
  targets: "cpp"
"""

{.emit:"""/*TYPESECTION*/
struct CppStruct {
  CppStruct(int x, char* y): x(x), y(y){}
  void doSomething() {}
  int x;
  char* y;
};
""".}
type
  CppStruct {.importcpp, inheritable.} = object
  ChildStruct = object of CppStruct
  HasCppStruct = object
    cppstruct: CppStruct 

proc constructCppStruct(a:cint = 5, b:cstring = "hello"): CppStruct {.importcpp: "CppStruct(@)", constructor.}
proc doSomething(this: CppStruct) {.importcpp.}
proc returnCppStruct(): CppStruct = discard
proc initChildStruct: ChildStruct = ChildStruct() 
proc makeChildStruct(): ChildStruct {.constructor:"""ChildStruct(): CppStruct(5, "10")""".} = discard
proc initHasCppStruct(x: cint): HasCppStruct =
  HasCppStruct(cppstruct: constructCppStruct(x))

proc main =
  var hasCppStruct = initHasCppStruct(2) #generates cppstruct = { 10 } inside the struct
  hasCppStruct.cppstruct.doSomething() 
  discard returnCppStruct() #generates result = { 10 } 
  discard initChildStruct() #generates ChildStruct temp ({}) bypassed with makeChildStruct
  (proc (s:CppStruct) = discard)(CppStruct()) #CppStruct temp ({10})
main()