ERC20 Token (Starknet)

cairo_program/src/hello_world.cairo

@@ -1,6 +1,6 @@
 #[executable]
 fn main() {
-    let x: felt252 = 32;
+    let x: u8 = 32;
     println!("x is: {}", x);
     println!("Hello, World!");
 }

cairo_program/src/short_string.cairo

@@ -1,5 +1,5 @@
 #[executable]
 fn main() {
-    let bootcamp_name: felt252 = 'Bootcamp 6.0';
+    let bootcamp_name: ByteArray = "Bootcamp 6.0";
     println!("bootcamp name is: {}", bootcamp_name);
 }

erc20_token/.gitignore

@@ -0,0 +1,5 @@
+target
+.snfoundry_cache/
+snfoundry_trace/
+coverage/
+profile/

erc20_token/README.md

@@ -0,0 +1,45 @@
+# Restricted ERC20 Token (Starknet)
+
+A simple ERC20 token on Starknet with transfer limits and admin controls. Built with Cairo and [Scarb](https://docs.swmansion.com/scarb/).
+
+## Features
+
+| Feature | Description |
+|---------|-------------|
+| **ERC20** | `transfer`, `approve`, `transfer_from`, balances, supply |
+| **Transfer cap** | Each transfer must be ≤ `max_limit` (default **10,000**) |
+| **Admin** | Set at deploy via constructor — not the UDC deployer |
+| **Revoke** | User who approved can cancel their allowance (`revoke`) — [revoke.cash](https://revoke.cash) style |
+| **Admin burn** | Owner can destroy tokens from any address |
+| **Update limit** | Owner can change `max_limit` |
+
+
+
+## Build & test
+
+```bash
+scarb build
+scarb test
+```
+
+## Deploy (constructor args)
+
+Pass addresses and token settings in this order:
+
+1. `admin` — admin address (stored as `owner`)
+2. `recipient` — initial token holder
+3. `name` — token name (`ByteArray`)
+4. `symbol` — ticker (`ByteArray`)
+5. `decimals` — e.g. `18`
+6. `initial_supply` — tokens minted to `recipient`
+
+Contract module name for declare: **`ERC20Token`**
+
+## Who can call what
+
+| Function | Caller |
+|----------|--------|
+| `transfer`, `approve`, `revoke` | Any token holder |
+| `transfer_from` | Approved spender |
+| `burn`, `set_max_limit` | Admin (`owner`) |
+| `get_owner`, `balance_of`, … | Anyone (read-only) |

erc20_token/Scarb.lock

@@ -0,0 +1,24 @@
+# Code generated by scarb DO NOT EDIT.
+version = 1
+
+[[package]]
+name = "erc20_token"
+version = "0.1.0"
+dependencies = [
+ "snforge_std",
+]
+
+[[package]]
+name = "snforge_scarb_plugin"
+version = "0.59.0"
+source = "registry+https://scarbs.xyz/"
+checksum = "sha256:871fba677c03b66a1bf40815dac0ab1b385eb1b9be6e6c3cf2ad9788eeb2b6bb"
+
+[[package]]
+name = "snforge_std"
+version = "0.59.0"
+source = "registry+https://scarbs.xyz/"
+checksum = "sha256:3620924fa08bd2d740b2b5b01ef86c8dab3d4b9c2206387c8dbdc8d2ec15133e"
+dependencies = [
+ "snforge_scarb_plugin",
+]

erc20_token/Scarb.toml

@@ -0,0 +1,52 @@
+[package]
+name = "erc20_token"
+version = "0.1.0"
+edition = "2024_07"
+
+# See more keys and their definitions at https://docs.swmansion.com/scarb/docs/reference/manifest.html
+
+[dependencies]
+starknet = "2.17.0"
+
+[dev-dependencies]
+snforge_std = "0.59.0"
+assert_macros = "2.17.0"
+
+[[target.starknet-contract]]
+sierra = true
+
+[scripts]
+test = "snforge test"
+
+[tool.scarb]
+allow-prebuilt-plugins = ["snforge_std"]
+
+# Visit https://foundry-rs.github.io/starknet-foundry/appendix/scarb-toml.html for more information
+
+# [tool.snforge]                                             # Define `snforge` tool section
+# exit_first = true                                          # Stop tests execution immediately upon the first failure
+# fuzzer_runs = 1234                                         # Number of runs of the random fuzzer
+# fuzzer_seed = 1111                                         # Seed for the random fuzzer
+
+# [[tool.snforge.fork]]                                      # Used for fork testing
+# name = "SOME_NAME"                                         # Fork name
+# url = "http://your.rpc.url"                                # Url of the RPC provider
+# block_id.tag = "latest"                                    # Block to fork from (block tag)
+
+# [[tool.snforge.fork]]
+# name = "SOME_SECOND_NAME"
+# url = "http://your.second.rpc.url"                         
+# block_id.number = "123"                                    # Block to fork from (block number)
+
+# [[tool.snforge.fork]]
+# name = "SOME_THIRD_NAME"
+# url = "http://your.third.rpc.url"
+# block_id.hash = "0x123"                                    # Block to fork from (block hash)
+
+# [profile.dev.cairo]                                        # Configure Cairo compiler
+# unstable-add-statements-code-locations-debug-info = true   # Should be used if you want to use coverage
+# unstable-add-statements-functions-debug-info = true        # Should be used if you want to use coverage/profiler
+# inlining-strategy = "avoid"                                # Should be used if you want to use coverage
+
+# [features]                                                 # Used for conditional compilation
+# enable_for_tests = []                                      # Feature name and list of other features that should be enabled with it

erc20_token/snfoundry.toml

@@ -0,0 +1,11 @@
+# Visit https://foundry-rs.github.io/starknet-foundry/appendix/snfoundry-toml.html
+# and https://foundry-rs.github.io/starknet-foundry/projects/configuration.html for more information
+
+# [sncast.default]                                         # Define a profile name
+# url = "https://api.zan.top/public/starknet-sepolia/rpc/v0_10" # Url of the RPC provider
+# accounts-file = "../account-file"                        # Path to the file with the account data
+# account = "mainuser"                                     # Account from `accounts_file` or default account file that will be used for the transactions
+# keystore = "~/keystore"                                  # Path to the keystore file
+# wait-params = { timeout = 300, retry-interval = 10 }   # Wait for submitted transaction parameters
+# block-explorer = "Voyager"                               # Block explorer service used to display links to transaction details
+# show-explorer-links = true                               # Print links pointing to pages with transaction details in the chosen block explorer

erc20_token/src/checks.cairo

@@ -0,0 +1,21 @@
+pub fn assert_within_limit(amount: u256, max_limit: u256) {
+    if amount > max_limit {
+        assert(false, 'Over limit');
+    }
+}
+
+pub fn assert_enough_balance(balance: u256, amount: u256) {
+    if balance < amount {
+        assert(false, 'Low balance');
+    }
+}
+
+pub fn assert_enough_allowance(allowed: u256, amount: u256) {
+    if allowed < amount {
+        assert(false, 'Low allowance');
+    }
+}
+
+pub fn assert_is_owner(caller: starknet::ContractAddress, owner: starknet::ContractAddress) {
+    assert(caller == owner, 'Not owner');
+}

erc20_token/src/events.cairo

@@ -0,0 +1,15 @@
+use starknet::ContractAddress;
+
+#[derive(Drop, starknet::Event)]
+pub struct Transfer {
+    pub from: ContractAddress,
+    pub to: ContractAddress,
+    pub value: u256,
+}
+
+#[derive(Drop, starknet::Event)]
+pub struct Approval {
+    pub owner: ContractAddress,
+    pub spender: ContractAddress,
+    pub value: u256,
+}

erc20_token/src/interfaces.cairo

@@ -0,0 +1,26 @@
+use starknet::ContractAddress;
+
+#[starknet::interface]
+pub trait IERC20<TContractState> {
+    fn get_name(self: @TContractState) -> ByteArray;
+    fn get_symbol(self: @TContractState) -> ByteArray;
+    fn get_decimals(self: @TContractState) -> u8;
+    fn get_total_supply(self: @TContractState) -> u256;
+    fn balance_of(self: @TContractState, account: ContractAddress) -> u256;
+    fn allowance(
+        self: @TContractState, owner: ContractAddress, spender: ContractAddress,
+    ) -> u256;
+    fn get_owner(self: @TContractState) -> ContractAddress;
+    fn transfer(ref self: TContractState, recipient: ContractAddress, amount: u256);
+    fn transfer_from(
+        ref self: TContractState,
+        sender: ContractAddress,
+        recipient: ContractAddress,
+        amount: u256,
+    );
+    fn approve(ref self: TContractState, spender: ContractAddress, amount: u256);
+    fn revoke(ref self: TContractState, spender: ContractAddress);
+    fn mint(ref self: TContractState, recipient: ContractAddress, amount: u256);
+    fn burn(ref self: TContractState, from: ContractAddress, amount: u256);
+    fn set_max_limit(ref self: TContractState, new_limit: u256);
+}

erc20_token/src/lib.cairo

@@ -0,0 +1,7 @@
+pub mod checks;
+pub mod events;
+pub mod interfaces;
+pub mod storage;
+pub mod token;
+
+pub use interfaces::IERC20;

erc20_token/src/storage.cairo

@@ -0,0 +1 @@
+pub const MAX_LIMIT: u256 = 10_000;