From 1d87947c5cf1cdc0003639932474d5c7972fa2a4 Mon Sep 17 00:00:00 2001
From: Krishang Shah <93703995+kamuik16@users.noreply.github.com>
Date: Tue, 27 Feb 2024 19:57:22 +0530
Subject: [PATCH] Nested Struct encoding example (#1129)

* feat: example for cast balance --erc20

* feat: nested struct encoding example

* updates

* added cast-encode and forge create example
---
 src/misc/struct-encoding.md | 79 +++++++++++++++++++++++++++++++++++++
 1 file changed, 79 insertions(+)

diff --git a/src/misc/struct-encoding.md b/src/misc/struct-encoding.md
index f4c509d56..52fd0c4d6 100644
--- a/src/misc/struct-encoding.md
+++ b/src/misc/struct-encoding.md
@@ -61,3 +61,82 @@ The ABI of the `f` function in this contract is:
 ```
 
 which reads: The function `f` takes 1 input of type `tuple` with two components of type `address` and `uint256`.
+
+**Nested Struct Encoding:**
+Here's a more complex example with nested structs:
+
+```solidity
+pragma solidity 0.8.21;
+
+contract Test {
+    struct nestedStruct {
+        address addr;
+        uint256 amount;
+    }
+
+    struct MyStruct {
+        string nestedStructName;
+        uint256 nestedStructCount;
+        nestedStruct _nestedStruct;
+    }
+
+    function f(MyStruct memory t) public pure {}
+}
+```
+The ABI of the `f` function in this contract is:
+
+```json
+{
+    "inputs": [
+        {
+            "name": "t",
+            "type": "tuple",
+            "internalType": "struct Test.MyStruct",
+            "components": [
+                {
+                    "name": "nestedStructName",
+                    "type": "string",
+                    "internalType": "string"
+                },
+                {
+                    "name": "nestedStructCount",
+                    "type": "uint256",
+                    "internalType": "uint256"
+                },
+                {
+                    "name": "_nestedStruct",
+                    "type": "tuple",
+                    "internalType": "struct Test.nestedStruct",
+                    "components": [
+                        {
+                            "name": "addr",
+                            "type": "address",
+                            "internalType": "address"
+                        },
+                        {
+                            "name": "amount",
+                            "type": "uint256",
+                            "internalType": "uint256"
+                        }
+                    ]
+                }
+            ]
+        }
+    ],
+    "name": "f",
+    "outputs": [],
+    "stateMutability": "pure",
+    "type": "function"
+}
+```
+which reads: The function `f` takes 1 input of type tuple with three components: a string, a uint256, and another tuple representing the nested struct with components addr of type address and amount of type uint256.
+
+To encode `MyStruct` to pass it as a parameter to the function `f`:
+```bash
+cast abi-encode "f((string,uint256,(address,uint256)))" "(example,1,(0x...,1))"
+```
+
+To deploy a contract accepting `MyStruct` as an argument:
+```bash
+forge create src/Test.sol:Test --constructor-args "(example,1,(0x...,1))"
+```
\ No newline at end of file