REPL

A dynamic shell that executes code in real time through a continuous read, eval, print, and loop cycle.

REPL environments (Read-Eval-Print Loop) provide immediate feedback by processing single user inputs and returning results instantly. This architecture (pioneered by Lisp in 1958) eliminates the traditional compile-link-run overhead found in static workflows. Modern implementations like IPython, Node.js, and the browser console allow developers to test logic, inspect variables, and debug complex algorithms on the fly. It is the industry standard for rapid prototyping and exploratory programming.

https://en.wikipedia.org/wiki/Read%E2%80%93eval%E2%80%93print_loop