] A read–eval–print loop (REPL), also known as an interactive toplevel or language shell, is a simple, interactive computer programming environment that takes single user inputs (i.e. single expressions), evaluates them, and returns the result to the user; a program written in a REPL environment is executed piecewise.
] there are many repls available today, some are language specific, some support multiple languages
] some are integrated into other programs, ex - learning to code tutorials