I'm interested in creating my own scheme interpreter and I've used /n?(vi)|m?|(e(x|d))/ for many years. For any external script the end user can stream back the

I'm interested in creating my own scheme interpreter and I've used /n?(vi)|m?|(e(x|d))/ for many years. For any external script the end user can stream back the transform simply by using the bang operator. How would I go about calling one of my scripts in vimscript so I could create named macros without the bang operator? Is there a library function which I can create a small system wrapper to call any language on the system to extend it without bang?