1.1.2 Scheme variables

Scheme variables can have any valid Scheme value, including a Scheme procedure.

Scheme variables are created with define:

guile> (define a 2)
guile>

Scheme variables can be evaluated at the guile prompt simply by typing the variable name:

guile> a
2
guile>

Scheme variables can be printed on the display by using the display function:

guile> (display a)
2guile>

Note that both the value 2 and the guile prompt guile showed up on the same line. This can be avoided by calling the newline procedure or displaying a newline character.

guile> (display a)(newline)
2
guile> (display a)(display "\n")
2
guile>

Once a variable has been created, its value can be changed with set!:

guile> (set! a 12345)
guile> a
12345
guile>