Feedback

and the REPL

            
+-------------+    +-----------+    +---------+    
| Change code |--->| Save file |--->|  Build  |
+-------------+    +-----------+    +---------+
       ^                                 |
       |                                 |
       |                                 V
   +-------+       +------+       +-------------+
   | Debug |<------| Test |<------| Reload page |
   +-------+       +------+       +-------------+
            
        

Why fast?

1. Creative flow
2. Unpredictability
3. Productivity!

Batch Processing

• 50's thru the 70's
• Computers are:
  Expensive Slow Monotasking
• Competition

Telegraphy

“Suppose that the programmer has a keyboard at the computer. Then they can try their program, interrogate individual pieces of data or code to find an error, make a change and try again.”

Lisp

• Artificial Intelligence
• Invented in 1958
• For the first time:
  Conditionals Recursion First class functions Garbage collection REPL

            
(loop (print (eval (read))))
            
        

            
+-------------+    +---------------+
| Change code |--->| Evaluate code |
+-------------+    +---------------+
       ^                   |
       |                   |
       |                   V
   +-------+           +------+
   | Debug |<----------| Test |
   +-------+           +------+
            
        

Replete

• A JavaScript REPL for your text editor.
• github.com/jamesdiacono/replete
• Plugins for:
  VSCode Sublime Neovim Emacs
• Evaluates modules in:
  Browsers Node.js Deno

Haiku

Inspiration

• What makes a REPL?, Eric Normand, 2019
• REPL-driven development in Clojure, Stuart Halloway, 2017

Feedback to james@diacono.com.au
Blog at james.diacono.com.au
Creations at github.com/jamesdiacono