Function Tcl_python

namd/src/ScriptTcl.C:372–456

}

int ScriptTcl::Tcl_python(ClientData, Tcl_Interp *interp, int argc, const char **argv) {
  if ( argc < 2 ) {
    Tcl_SetResult(interp,(char*)"args: script",TCL_VOLATILE);
    return TCL_ERROR;
  }
  namd_python_initialize(interp);
  PyObject *dict = PyModule_GetDict(PyImport_AddModule("__main__"));

  const char *script = argv[1];
  int token = Py_eval_input;

  Tcl_DString scr;
  Tcl_DStringInit(&scr);
  if ( argc > 2 ) {
    Tcl_DStringAppend(&scr,argv[1],-1);
    for ( int i = 2; i < argc; ++i ) {
      Tcl_DStringAppend(&scr," ",-1);
      Tcl_DStringAppend(&scr,argv[i],-1);
    }
    script = Tcl_DStringValue(&scr);
  } else {
    while ( script[0] == ' ' || script[0] == '\t' ) ++script;
    for ( int i=0; script[i]; ++i ) {
      if ( script[i] == '\n' ) {
        token = Py_file_input;
        script = argv[1];
        break;
      }
    }
  }

  PyObject *result = PyRun_String(script, token, dict, dict);
  Tcl_ResetResult(interp);  // Python may have called Tcl
  Tcl_DStringFree(&scr);

  if ( PyErr_Occurred() ) {
    if ( result ) NAMD_bug("PyErr_Occurred indicates error but PyRun does not");
    // PyErr_Print();
    Tcl_AppendResult(interp, "error from python interpreter\n", NULL);
    PyObject *type, *value, *traceback, *str;
    PyErr_Fetch(&type, &value, &traceback);

    if ( ! traceback ) {
      traceback = Py_None;
      Py_INCREF(Py_None);
    }

    PyObject *mod = PyImport_ImportModule("traceback");
    if ( ! mod ) return TCL_ERROR;

    PyObject *func = PyObject_GetAttrString(mod, "format_exception");
    if ( ! func ) return TCL_ERROR;

    // TODO understand why this call fails in Python3 in cases where the
    // traceback is not None
    PyObject *list = PyObject_CallFunctionObjArgs(func, type, value, traceback, NULL);
    if ( ! list ) return TCL_ERROR;