NEP: Programmable NEP-5 Token Extension

NEP-Programmable-NEP-5-Token-Extension.mediawiki

@@ -0,0 +1,68 @@
+<pre>
+  NEP: <to be assigned>
+  Title: Programmable NEP-5 Token Extension
+  Authors: Dean van Dugteren (dean@nos.io), Jeroen Peeters (contact@jeroenpeeters.me)
+  Type: Standard
+  Status: Draft
+  Created: 2018-08-09
+  Revisision: 2018/08/10
+  Requires: NEP-5
+</pre>
+
+===NOTE: To be updated===
+
+==Abstract==
+
+This NEP introduces a memory-efficient method for allowing conditional NEP-5 token transactions between users and third party smart contracts without the need for off-chain listeners. The methods take into account future changes in invocation fees, so as to make it work efficiently in multiple scenarios.
+
+==Motivation==
+All tokens should be ''programmable''. By programmable we mean that tokens should be conditionally transacted and held between users and smart contracts alike.
+
+Presently, dApp smart contracts handle conditional transactions (e.g. staking a NEP5 token with a release condition) via off-chain listeners that send invocations based on certain triggers such as NEP5 Transaction Notification events.
+
+This NEP proposes the following solution:
+
+
+* A separate transfer method and operation <code>transferAndInvoke(from, to, amount, scriptHash, operation, args)</code> that makes a transaction of NEP5 tokens using <code>from, to, amount</code> and calls a dynamic invocation on the <code>scriptHash</code> script hash, using <code>(string) from, (string) to, (bigint) amount, (string) operation, (list) args</code> in the arguments list to be used in the dynamic invocation.
+
+The ''transferAndInvoke'' operation can be called by web-based applications integrating with ''neon-js'', nOS dApps, and applications utilizing NeoLink or the NEX plug-in. Additionally, wallet applications such as ''Neon Wallet'' can present the user with an option whether their transaction is intended for a user or a smart contract (effectively switching between ''transfer'' and ''transferAndInvoke'' operations).
+
+One of the use cases is that an ICO smart contract can listen to transactions made to a different address, since the target receiver <code>to</code> and target smart contract <code>scriptHash</code> can differ.
+Use cases also include token staking, conditional token releases, and anything else that a smart contract can do with ''programmable tokens''.
+
+To achieve this, the NEP-5 token will need to be able to make dynamic invocations.
+
+==Specification==
+
+We propose the following methods to be implemented in any token contract that is looking to have a memory-efficient ''programmable'' NEP5 token:
+
+[[File:https://user-images.githubusercontent.com/31391056/43956007-d3125fbe-9ca2-11e8-8e31-757a6768ad04.png]]
+
+===Methods===
+
+====transferAndInvoke====
+
+* Syntax: <code>public static bool transferAndInvoke(from, to, amount, scriptHash, operation, args)</code>
+
+* Remarks:
+** This method (with operation ''transferAndInvoke'') executes the NEP5 token's <code>transfer(from, to, amount)</code> function, and dynamically invokes the script hash derived from the <code>scriptHash</code> parameter, providing <code>from, to, amount, scriptHash, operation, args</code> as parameters for the receiving smart contract.
+
+
+
+==Example==
+User/application calls NEP-5 contract with this extension like: 
+ transferAndInvoke [ myAddress, yourAddress, 100, dAppContractScriptHash, "processTransaction", ["This is a string to be handled by the dApp smart contract", "another string", 10, "as many as you want"] ]
+
+
+With `transferAndInvoke`, the NEP5 contract makes a dynamic invocation to `dAppContractScriptHash` with operation <code>processTransactions</code> and an args list:
+
+ args[0] : from
+ args[1] : to
+ args[2] : amount
+ args[3] : "This is a string to be handled by the dApp smart contract"
+ args[4] : "another string"
+ args[5] : 10
+ args[6] : "as many as you want"
+
+==Implementation==
+TBD