Node:The REPL, Next:Syntax Summary, Previous:Evaluating, Up:About Expressions
If you start Guile without specifying a particular program for it to execute, Guile enters its standard Read Evaluate Print Loop -- or REPL for short. In this mode, Guile repeatedly reads in the next Scheme expression that the user types, evaluates it, and prints the resulting value.
The REPL is a useful mechanism for exploring the evaluation behaviour
described in the previous subsection. If you type string-append,
for example, the REPL replies #<primitive-procedure
string-append>, illustrating the relationship between the variable
string-append and the procedure value stored in that variable.
In this manual, the notation => is used to mean "evaluates
to". Wherever you see an example of the form
expression => result
feel free to try it out yourself by typing expression into the REPL and checking that it gives the expected result.