When you start up Guile by typing just
guile, without a
-c argument or the name of a script to execute, you get an
interactive interpreter where you can enter Scheme expressions, and
Guile will evaluate them and print the results for you. Here are some
guile> (+ 3 4 5) 12 guile> (display "Hello world!\n") Hello world! guile> (values 'a 'b) a b
This mode of use is called a REPL, which is short for “Read-Eval-Print Loop”, because the Guile interpreter first reads the expression that you have typed, then evaluates it, and then prints the result.