3 ms·

I hear this "code as system is running" a lot. Doesn't it complicate our reasoning about the program as compared to simple text files? I haven't heard the other

• Jtsummers 6y ago
  You still have the simple text files, but while you're developing (and perhaps in exceptional circumstances while it's running) you interact with it in a live fashion. But the source code is still there, and the whole thing can be recreated from scratch if you kill the image by loading the code. This lets you do things like (stupid trivial example follows, Common Lisp not Clojure) write a function from inside out in the REPL, then move the code to source: > (+ 1 2) 3 > (let ((x 1)) (+ x 2)) 3 (defun add-two (x) ;; in a source file (+ x 2)) > (add-two 1) ;; after evaluating/compiling the above 3 Imagine that these were more complicated things, like you're using a web API and getting JSON files and parsing them. You can develop it interactively, and as you verify that things are correct, you can migrate them to functions (and add tests to really do the verification part).