Available since 1.0 (source)
  • (condp pred expr & clauses)
Takes a binary predicate, an expression, and a set of clauses.
Each clause can take the form of either:
 test-expr result-expr
 test-expr :>> result-fn
 Note :>> is an ordinary keyword.
 For each clause, (pred test-expr expr) is evaluated. If it returns
logical true, the clause is a match. If a binary clause matches, the
result-expr is returned, if a ternary clause matches, its result-fn,
which must be a unary function, is called with the result of the
predicate as its argument, the result of that call being the return
value of condp. A single default expression can follow the clauses,
and its value will be returned if no clause matches. If no default
expression is provided and no clause matches, an
IllegalArgumentException is thrown.