(cond ..clauses) clauses: zero or more arrs
Tests several conditions in turn.
Each clause must be an array,
condition in turn. When a
condition evaluates to something other
#n, the remaining forms in that clause are evaluated, and the value of the
last form in the clause is returned. Any remaining clauses are not evaluated.
If all of the conditions evaluate to
cond form as a whole evaluates
The final clause may use the symbol
else in place of its condition. When all other
conditions have evaluated to
else clause will be evaluated and
(cond ((>= 5 10) (bail "something is wrong")) (else (prn "five is less than ten")))