Contract of module/namespace

For technical reasons, contracts are not namespaces, and namespaces are not contracts. In order to use a namespace that contains functions with the type of an entrypoint, and that are decorated as @entry, as a contract, for example for testing, we need the built-in function contract_of. It is built-in (and a keyword) because it takes a module as parameter, and the type system of LIGO has also a predefined type for its return value: module_contract<param, storage>, but not the full type.

type storage = int;

type @return = [list<operation>, storage];

namespace C {

@entry

const decrement = (param: int, storage: storage) : @return =>

[[], storage - param];

@entry

const increment = (param: int, storage: storage) : @return =>

[[], storage + param];

@entry

const reset = (_unit: unit, _storage: storage) : @return =>

[[], 0];

}

const test_initial_storage = () : unit => {

const init_storage = 42;

const fee = 0mutez;

const orig = Test.Next.originate (contract_of(C), init_storage, fee);

const new_storage = Test.Next.Typed_address.get_storage(orig.taddr);

assert(new_storage == init_storage);

}