(require mzlib/contract)

This library is designed as a backwards compatible library for old uses of contracts. It should not be used for new libraries; use scheme/contract instead.

The main differences: the function contract syntax is more regular and function contracts now support keywords, and union is now or/c.

The mzlib/contract library re-exports many bindings from scheme/contract:

	</c		flat-rec-contract
	<=/c		guilty-party
	=/c		integer-in
	>/c		list/c
	>=/c		listof
	and/c		make-none/c
	any		make-proj-contract
	any/c		natural-number/c
	between/c		none/c
	box-immutable/c		not/c
	build-compound-type-name		one-of/c
	coerce-contract		or/c
	cons/c		parameter/c
	contract		printable/c
	contract-first-order-passes?		promise/c
	contract-violation->string		provide/contract
	contract?		raise-contract-error
	define-contract-struct		real-in
	false/c		recursive-contract
	flat-contract		string/len
	flat-contract-predicate		symbols
	flat-contract?		syntax/c
	flat-murec-contract		vector-immutable/c
	flat-named-contract		vector-immutableof

It also provides the old version of the following forms:

The define/contract form treats individual definitions as units of blame. The definition itself is responsible for positive (co-variant) positions of the contract and each reference to id (including those in the initial value expression) must meet the negative positions of the contract.

Error messages with define/contract are not as clear as those provided by provide/contract, because define/contract cannot detect the name of the definition where the reference to the defined variable occurs. Instead, it uses the source location of the reference to the variable as the name of that definition.