Callback.sol

Author: jamesbachini

contracts/Callback.sol

@@ -0,0 +1,28 @@
+// SPDX-License-Identifier: MIT
+pragma solidity >=0.8.0;
+
+contract Parent {
+    uint public parentVariable;
+
+    function parentFunc(uint _parentVariable, function(uint) external _callback) public {
+        parentVariable = _parentVariable;
+         _callback(_parentVariable * 2);
+    }
+}
+
+contract Child {
+    address public parentAddress;
+    uint public childVariable;
+
+    constructor(address _parentAddress) {
+        parentAddress = _parentAddress;
+    }
+    
+    function run(uint _newVar) public {
+        Parent(parentAddress).parentFunc(_newVar, this.callback);
+    }
+    
+    function callback(uint _childVariable) external {
+        childVariable = _childVariable * 2;
+    }
+}