From R2RS:
Data and procedures and the values they amass,
Higher-order functions to combine and mix and match,
Objects with their local state, the messages they pass,
A property, a package, the control point for a catch–
In the Lambda Order they are all first-class.
One Thing to name them all, One Thing to define them,
One Thing to place them in environments and bind them,
In the Lambda order they are all first-class.
(Hat tip Mark H Weaver over at guile-devel)
