Add ERC20 preset

docs/modules/ROOT/pages/erc20.adoc

@@ -241,3 +241,13 @@ mod MyToken {
 This contract expects a `decimals` argument in the constructor and uses an internal function to write the decimals to storage.
 Note that the `decimals` state variable must be defined in the contract's storage because this variable does not exist in the component offered by OpenZeppelin Contracts for Cairo.
 It's important to include a custom ERC20 metadata implementation and NOT use the Contracts for Cairo `ERC20MetadataImpl` in this specific case since the `decimals` method will always return `18`.
+
+== Preset ERC20 contract
+
+:erc20-preset: link:https://github.com/OpenZeppelin/cairo-contracts/blob/release-v0.8.0-beta.0/src/presets/erc20.cairo[ERC20 preset contract]
+
+OpenZeppelin Contracts for Cairo offers an {erc20-preset}.
+The contract provides basic functionality and uses a fixed-supply mechanism for token distribution. 
+
+This contract is ready to deploy without having to write any additional Cairo code.
+It can be used as-is for quick prototyping and testing.

docs/modules/ROOT/pages/guides/erc20-supply.adoc

@@ -42,20 +42,20 @@ mod MyToken {
     #[constructor]
     fn constructor(
         ref self: ContractState,
-        initial_supply: u256,
+        fixed_supply: u256,
         recipient: ContractAddress
     ) {
         let name = 'MyToken';
         let symbol = 'MTK';
 
         self.erc20.initializer(name, symbol);
-        self.erc20._mint(recipient, initial_supply);
+        self.erc20._mint(recipient, fixed_supply);
     }
 }
 ----
 
 In the constructor, we're first calling the ERC20 initializer to set the token name and symbol.
-Next, we're calling the internal `_mint` function which creates `initial_supply` of tokens and allocates them to `recipient`.
+Next, we're calling the internal `_mint` function which creates `fixed_supply` of tokens and allocates them to `recipient`.
 Since the internal `_mint` is not exposed in our contract, it will not be possible to create any more tokens.
 In other words, we've implemented a fixed token supply!
 

src/lib.cairo

@@ -1,6 +1,7 @@
 mod access;
 mod account;
 mod introspection;
+mod presets;
 mod security;
 #[cfg(test)]
 mod tests;

src/presets.cairo

@@ -0,0 +1,2 @@
+mod erc20;
+use erc20::ERC20;

src/presets/erc20.cairo

@@ -0,0 +1,55 @@
+// SPDX-License-Identifier: MIT
+// OpenZeppelin Contracts for Cairo v0.8.0-beta.0 (presets/erc20.cairo)
+
+/// # ERC20 Preset Contract
+///
+/// The ERC20 preset contract offers basic functionality and provides a
+/// fixed-supply mechanism for token distribution. The fixed supply is
+/// set in the constructor.
+#[starknet::contract]
+mod ERC20 {
+    use openzeppelin::token::erc20::ERC20Component;
+    use starknet::ContractAddress;
+
+    component!(path: ERC20Component, storage: erc20, event: ERC20Event);
+
+    #[abi(embed_v0)]
+    impl ERC20Impl = ERC20Component::ERC20Impl<ContractState>;
+    #[abi(embed_v0)]
+    impl ERC20MetadataImpl = ERC20Component::ERC20MetadataImpl<ContractState>;
+    #[abi(embed_v0)]
+    impl SafeAllowanceImpl = ERC20Component::SafeAllowanceImpl<ContractState>;
+    #[abi(embed_v0)]
+    impl ERC20CamelOnlyImpl = ERC20Component::ERC20CamelOnlyImpl<ContractState>;
+    #[abi(embed_v0)]
+    impl SafeAllowanceCamelImpl =
+        ERC20Component::SafeAllowanceCamelImpl<ContractState>;
+    impl InternalImpl = ERC20Component::InternalImpl<ContractState>;
+
+    #[storage]
+    struct Storage {
+        #[substorage(v0)]
+        erc20: ERC20Component::Storage
+    }
+
+    #[event]
+    #[derive(Drop, starknet::Event)]
+    enum Event {
+        #[flat]
+        ERC20Event: ERC20Component::Event
+    }
+
+    /// Sets the token `name` and `symbol`.
+    /// Mints `fixed_supply` tokens to `recipient`.
+    #[constructor]
+    fn constructor(
+        ref self: ContractState,
+        name: felt252,
+        symbol: felt252,
+        fixed_supply: u256,
+        recipient: ContractAddress
+    ) {
+        self.erc20.initializer(name, symbol);
+        self.erc20._mint(recipient, fixed_supply);
+    }
+}

src/tests.cairo

@@ -2,6 +2,7 @@ mod access;
 mod account;
 mod introspection;
 mod mocks;
+mod presets;
 mod security;
 mod token;
 mod upgrades;

src/tests/presets.cairo

@@ -0,0 +1 @@
+mod test_erc20;