In a language like guile scheme or racket this could be implemented as a macro. In guile, the (define-inlinable ...) Is already defined as a macro, and while do

In a language like guile scheme or racket this could be implemented as a macro. In guile, the (define-inlinable ...) Is already defined as a macro, and while doing it in reverse would be harder it could be done and tested in an hour. I would probably do it by overriding (define ...) to make it also store the source of the function somewhere and make (inline ...) just insert it as an anonymous function: (define (square x) (* x x)) (inline square 5) The last call would be expanded to ((lambda (x) (* x x) 5) Which the guile inliner always in-lines.