Package: ape-roll
ape-rollape-roll is a planner for the operation-chaining/scripting languageweiroll.
ape-roll is inspired byweiroll.js.It provides an easy-to-use API for generating weiroll programs that can be passed to any compatible implementation.Installationpip install ape-roll==0.0.2where0.0.2is the latest version.UsageWrapping contractsWeiroll programs consist of a sequence of calls to functions in external contracts. These calls can be delegate calls to dedicated library contracts, or standard/static calls to external contracts. Before you can start creating a weiroll program, you must create interfaces for at least one contract you intend to use.The easiest way to do this is by wrapping ape contract instances:ape_contract=ape.Contract(address)contract=ape_roll.WeirollContract(ape_contract)This will produce a contract object that generates delegate calls to the ape contract inWeirollContract.To create a delegate to an external contract, usecreateLibrary:ape_contract=ape.Contract(address)# Makes calls using CALLcontract=ape_roll.WeirollContract.createContract(ape_contract)# Makes calls using STATICCALLcontract=ape_roll.WeirollContract.createLibrary(ape_contract)You can just repeat this for each contract you'd like to use. A weirollWeirollContractobject can be reused across as many planner instances as you wish; there is no need to construct them again for each new program.Planning programsFirst, instantiate a planner:planner=ape_roll.WeirollPlanner()Next, add one or more commands to execute:ret=planner.add(contract.func(a,b))Return values from one invocation can be used in another one:planner.add(contract.func2(ret))Remember to wrap each call to a contract inplanner.add. Attempting to pass the result of one contract function directly to another will not work - each one needs to be added to the planner!For calls to external contracts, you can also pass a value in ether to send:planner.add(contract.func(a,b).withValue(c))withValuetakes the same argument types as contract functions so that you can pass the return value of another function or a literal value. You cannot combinewithValuewith delegate calls (eg, calls to a library created withContract.newLibrary) or static calls.Likewise, if you want to make a particular call static, you can use.staticcall():result=planner.add(contract.func(a,b).staticcall())Weiroll only supports functions that return a single value by default. If your function returns multiple values, though, you can instruct weiroll to wrap it in abytes, which subsequent commands can decode and work with:ret=planner.add(contract.func(a,b).rawValue())Once you are done planning operations, generate the program:commands,state=planner.plan()SubplansIn some cases, it may be useful to instantiate nested instances of the weiroll VM - for example, when using flash loans, or other systems that function by making a callback to your code. The weiroll planner supports this via 'subplans'.To make a subplan, construct the operations that should take place inside the nested instance usually, then pass the planner object to a contract function that executes the subplan, and pass that to the outer planner's.addSubplan()function instead of.add().For example, suppose you want to call a nested instance to do some math:subplanner=WeirollPlanner()sum=subplanner.add(Math.add(1,2))planner=WeirollPlanner()planner.addSubplan(Weiroll.execute(subplanner,subplanner.state))planner.add(events.logUint(sum))commands,state=planner.plan()Subplan functions must specify which argument receives the current state using the special variablePlanner.stateand take exactly one subplanner and one state argument. Subplan functions must either return an updated state or nothing.If a subplan returns an updated state, return values created in a subplanner, such assumabove, can be referenced in the outer scope, and even in other subplans, as long as they are referenced after the command that produces them. Subplans that do not return updated state are read-only, and return values defined inside them cannot be referenced outside them.More examplesReviewtestsfor more examples.Credits@WyseNynjafor the original implementation