2 Contract

(require (planet dvanhorn/ralist:1:11/contract))

Just like (planet dvanhorn/ralist:1:11/main), but with contracts.

(count=/c n) → flat-contract?

n : natural-number/c

Returns a flat contract that requires the input to have a count equal to n.

(count>/c n) → flat-contract?

n : natural-number/c

Returns a flat contract that requires the input to have a count greater than n.

(is-true/c x) → flat-contract?

x : any/c

Returns a flat contract that requires nothing of its input, and returns x, i.e. it produces a contract for the predicate (lambda (_) x).

(arity-includes/c n) → flat-contract?

n : natural-number/c

Returns a flat contract that requires its input to be a procedure accepting at least n arguments, i.e. it produces a contract for the predicate,

(lambda (x)

(and (procedure? x)

(procedure-arity-includes? x n)))