create_hist_field
hist_field->operands[0] = create_hist_field(hist_data, field, fl, NULL);
ref_field = create_hist_field(var_field->hist_data, NULL, flags, NULL);
alias = create_hist_field(hist_data, NULL, flags, var_name);
field = create_hist_field(hist_data, NULL, *flags, var_name);
hist_field = create_hist_field(hist_data, field, *flags, var_name);
expr = create_hist_field(hist_data, NULL, flags, var_name);
expr = create_hist_field(hist_data, NULL, flags, var_name);
create_hist_field(hist_data, NULL, HIST_FIELD_FL_HITCOUNT, NULL);
hist_field = create_hist_field(hist_data, NULL, flags, NULL);