Edit the document below; results appear inline as you type. The document is self-contained: it imports the stdlib it needs, so it evaluates even against an empty knowledge base.
import nelumbo.integers
Integer ::= fib(<Integer>)
Integer n
fib(n) == n if n<=1, fib(n-1)+fib(n-2) if n>1
Integer r
fib(7)=r ?