5aed8b3ef5
Functions must be annotated as `stateful` in order to - Update the contract state (using `put`) - Call `Chain.spend` or other primitive functions that cost tokens - Call an Oracle or AENS function that requires a signature - Make a remote call with a non-zero value - Construct a lambda calling a stateful function It does not need to be stateful to - Read the contract state - Call another contract with value=0, even when the remote function is stateful
113 lines
4.0 KiB
Plaintext
113 lines
4.0 KiB
Plaintext
contract Oracles =
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type fee = int
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type ttl = Chain.ttl
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type query_t = string
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type answer_t = int
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type oracle_id = oracle(query_t, answer_t)
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type query_id = oracle_query(query_t, answer_t)
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stateful function registerOracle(acct : address,
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qfee : fee,
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ttl : ttl) : oracle_id =
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Oracle.register(acct, qfee, ttl)
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stateful function registerIntIntOracle(acct : address,
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qfee : fee,
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ttl : ttl) : oracle(int, int) =
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Oracle.register(acct, qfee, ttl)
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stateful function registerStringStringOracle(acct : address,
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qfee : fee,
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ttl : ttl) : oracle(string, string) =
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Oracle.register(acct, qfee, ttl)
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stateful function signedRegisterOracle(acct : address,
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sign : signature,
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qfee : fee,
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ttl : ttl) : oracle_id =
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Oracle.register(acct, qfee, ttl, signature = sign)
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function queryFee(o : oracle_id) : fee =
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Oracle.query_fee(o)
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stateful function createQuery(o : oracle_id,
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q : query_t,
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qfee : fee,
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qttl : ttl,
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rttl : ttl) : query_id =
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require(qfee =< Call.value, "insufficient value for qfee")
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Oracle.query(o, q, qfee, qttl, rttl)
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// Do not use in production!
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stateful function unsafeCreateQuery(o : oracle_id,
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q : query_t,
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qfee : fee,
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qttl : ttl,
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rttl : ttl) : query_id =
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Oracle.query(o, q, qfee, qttl, rttl)
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// Do not use in production!
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stateful function unsafeCreateQueryThenErr(o : oracle_id,
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q : query_t,
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qfee : fee,
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qttl : ttl,
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rttl : ttl) : query_id =
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let res = Oracle.query(o, q, qfee, qttl, rttl)
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require(qfee >= 100000000000000000, "causing a late error")
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res
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stateful function extendOracle(o : oracle_id,
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ttl : ttl) : () =
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Oracle.extend(o, ttl)
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stateful function signedExtendOracle(o : oracle_id,
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sign : signature, // Signed oracle address
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ttl : ttl) : () =
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Oracle.extend(o, signature = sign, ttl)
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stateful function respond(o : oracle_id,
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q : query_id,
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r : answer_t) : () =
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Oracle.respond(o, q, r)
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stateful function signedRespond(o : oracle_id,
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q : query_id,
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sign : signature,
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r : answer_t) : () =
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Oracle.respond(o, q, signature = sign, r)
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function getQuestion(o : oracle_id,
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q : query_id) : query_t =
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Oracle.get_question(o, q)
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function hasAnswer(o : oracle_id,
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q : query_id) =
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switch(Oracle.get_answer(o, q))
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None => false
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Some(_) => true
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function getAnswer(o : oracle_id,
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q : query_id) : option(answer_t) =
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Oracle.get_answer(o, q)
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datatype complexQuestion = Why(int) | How(string)
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datatype complexAnswer = NoAnswer | Answer(complexQuestion, string, int)
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stateful function complexOracle(question) =
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let o = Oracle.register(Contract.address, 0, FixedTTL(1000)) : oracle(complexQuestion, complexAnswer)
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let q = Oracle.query(o, question, 0, RelativeTTL(100), RelativeTTL(100))
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Oracle.respond(o, q, Answer(question, "magic", 1337))
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Oracle.get_answer(o, q)
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stateful function signedComplexOracle(question, sig) =
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let o = Oracle.register(signature = sig, Contract.address, 0, FixedTTL(1000)) : oracle(complexQuestion, complexAnswer)
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let q = Oracle.query(o, question, 0, RelativeTTL(100), RelativeTTL(100))
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Oracle.respond(o, q, Answer(question, "magic", 1337), signature = sig)
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Oracle.get_answer(o, q)
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private function require(b : bool, err : string) =
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if(!b) abort(err)
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