Application chapter: grammar, wording, typos, !addr.is_zero -> `add…

…r.is_non_zero` (#213)

* upgradeable > use is_non_zero

* simple_vault > grammar

* not is_zero -> is_non_zero

* update sbe links

* staking > wording

* amm > fix brackets + grammar

---------

Co-authored-by: Nenad <nenad@better.giving>

listings/applications/constant_product_amm/src/contracts.cairo

@@ -147,7 +147,7 @@ pub mod ConstantProductAmm {
  assert(reserve0 * amount1 == reserve1 * amount0, 'x / y != dx / dy');
  }
 
- // How much shares to mint?
+ // How many shares to mint?
  //
  // f(x, y) = value of liquidity
  // We will define f(x, y) = sqrt(xy)
@@ -178,11 +178,11 @@ pub mod ConstantProductAmm {
  //
  // Multiply by sqrt(x) / sqrt(x)
  // Equation 2 = (sqrt(x^2y + 2xydx + dx^2 * y) - sqrt(x^2y)) / sqrt(x^2y)
- // = (sqrt(y)(sqrt(x^2 + 2xdx + dx^2) - sqrt(x^2)) / (sqrt(y)sqrt(x^2))
+ // = (sqrt(y)(sqrt(x^2 + 2xdx + dx^2) - sqrt(x^2))) / (sqrt(y)sqrt(x^2))
  // sqrt(y) on top and bottom cancels out
  //
  // --- Equation 3 ---
- // Equation 2 = (sqrt(x^2 + 2xdx + dx^2) - sqrt(x^2)) / (sqrt(x^2)
+ // Equation 2 = (sqrt(x^2 + 2xdx + dx^2) - sqrt(x^2)) / sqrt(x^2)
  // = (sqrt((x + dx)^2) - sqrt(x^2)) / sqrt(x^2)
  // = ((x + dx) - x) / x
  // = dx / x

listings/applications/erc20/src/token.cairo

@@ -165,8 +165,8 @@ pub mod erc20 {
  recipient: ContractAddress,
  amount: felt252
  ) {
- assert(!sender.is_zero(), Errors::TRANSFER_FROM_ZERO);
- assert(!recipient.is_zero(), Errors::TRANSFER_TO_ZERO);
+ assert(sender.is_non_zero(), Errors::TRANSFER_FROM_ZERO);
+ assert(recipient.is_non_zero(), Errors::TRANSFER_TO_ZERO);
  self.balances.write(sender, self.balances.read(sender) - amount);
  self.balances.write(recipient, self.balances.read(recipient) + amount);
  self.emit(Transfer { from: sender, to: recipient, value: amount });
@@ -188,13 +188,13 @@ pub mod erc20 {
  spender: ContractAddress,
  amount: felt252
  ) {
- assert(!spender.is_zero(), Errors::APPROVE_TO_ZERO);
+ assert(spender.is_non_zero(), Errors::APPROVE_TO_ZERO);
  self.allowances.write((owner, spender), amount);
  self.emit(Approval { owner, spender, value: amount });
  }
 
  fn mint(ref self: ContractState, recipient: ContractAddress, amount: felt252) {
- assert(!recipient.is_zero(), Errors::MINT_TO_ZERO);
+ assert(recipient.is_non_zero(), Errors::MINT_TO_ZERO);
  let supply = self.total_supply.read() + amount;
  self.total_supply.write(supply);
  let balance = self.balances.read(recipient) + amount;

listings/applications/staking/src/contract.cairo

@@ -126,7 +126,7 @@ pub mod StakingContract {
 
  self.reward_rate.write(rate);
 
- // even if the previous reward duration was not finished, we reset the finish_at variable
+ // even if the previous reward duration has not finished, we reset the finish_at variable
  self.finish_at.write(block_timestamp + self.duration.read());
  self.last_updated_at.write(block_timestamp);
 
@@ -216,7 +216,7 @@ pub mod StakingContract {
  }
 
  fn send_rewards_finished_event(ref self: ContractState) {
- // check if we send a RewardsFinished event
+ // check whether we should send a RewardsFinished event
  if self.last_updated_at.read() == self.finish_at.read() {
  let total_rewards = self.reward_rate.read() * self.duration.read();
 

listings/applications/upgradeable_contract/src/upgradeable_contract_v0.cairo

@@ -32,7 +32,7 @@ pub mod UpgradeableContract_V0 {
  impl UpgradeableContract of super::IUpgradeableContract<ContractState> {
  // ANCHOR: upgrade
  fn upgrade(ref self: ContractState, impl_hash: ClassHash) {
- assert(!impl_hash.is_zero(), 'Class hash cannot be zero');
+ assert(impl_hash.is_non_zero(), 'Class hash cannot be zero');
  starknet::syscalls::replace_class_syscall(impl_hash).unwrap_syscall();
  self.emit(Event::Upgraded(Upgraded { implementation: impl_hash }))
  }

listings/applications/upgradeable_contract/src/upgradeable_contract_v1.cairo

@@ -29,7 +29,7 @@ pub mod UpgradeableContract_V1 {
  #[abi(embed_v0)]
  impl UpgradeableContract of super::IUpgradeableContract<ContractState> {
  fn upgrade(ref self: ContractState, impl_hash: ClassHash) {
- assert(!impl_hash.is_zero(), 'Class hash cannot be zero');
+ assert(impl_hash.is_non_zero(), 'Class hash cannot be zero');
  starknet::syscalls::replace_class_syscall(impl_hash).unwrap_syscall();
  self.emit(Event::Upgraded(Upgraded { implementation: impl_hash }))
  }

po/es.po

@@ -2746,7 +2746,7 @@ msgid ""
 "# impl UpgradeableContract of super::IUpgradeableContract<ContractState> "
 "{\n"
 " fn upgrade(ref self: ContractState, impl_hash: ClassHash) {\n"
-" assert(!impl_hash.is_zero(), 'Class hash cannot be zero');\n"
+" assert(impl_hash.is_non_zero(), 'Class hash cannot be zero');\n"
 " starknet::replace_class_syscall(impl_hash).unwrap_syscall();\n"
 " self.emit(Event::Upgraded(Upgraded { implementation: "
 "impl_hash }))\n"
@@ -2794,7 +2794,7 @@ msgstr ""
 "# impl UpgradeableContract of super::IUpgradeableContract<ContractState> "
 "{\n"
 " fn upgrade(ref self: ContractState, impl_hash: ClassHash) {\n"
-" assert(!impl_hash.is_zero(), 'Class hash cannot be zero');\n"
+" assert(impl_hash.is_non_zero(), 'Class hash cannot be zero');\n"
 " starknet::replace_class_syscall(impl_hash).unwrap_syscall();\n"
 " self.emit(Event::Upgraded(Upgraded { implementation: "
 "impl_hash }))\n"
@@ -7780,7 +7780,7 @@ msgid ""
 " impl UpgradeableContract of super::IUpgradeableContract<ContractState> "
 "{\n"
 " fn upgrade(ref self: ContractState, impl_hash: ClassHash) {\n"
-" assert(!impl_hash.is_zero(), 'Class hash cannot be zero');\n"
+" assert(impl_hash.is_non_zero(), 'Class hash cannot be zero');\n"
 " starknet::replace_class_syscall(impl_hash).unwrap_syscall();\n"
 " self.emit(Event::Upgraded(Upgraded { implementation: "
 "impl_hash }))\n"
@@ -7826,7 +7826,7 @@ msgstr ""
 " impl UpgradeableContract of super::IUpgradeableContract<ContractState> "
 "{\n"
 " fn upgrade(ref self: ContractState, impl_hash: ClassHash) {\n"
-" assert(!impl_hash.is_zero(), 'Class hash cannot be zero');\n"
+" assert(impl_hash.is_non_zero(), 'Class hash cannot be zero');\n"
 " starknet::replace_class_syscall(impl_hash).unwrap_syscall();\n"
 " self.emit(Event::Upgraded(Upgraded { implementation: "
 "impl_hash }))\n"
@@ -7890,7 +7890,7 @@ msgid ""
 " impl UpgradeableContract of super::IUpgradeableContract<ContractState> "
 "{\n"
 " fn upgrade(ref self: ContractState, impl_hash: ClassHash) {\n"
-" assert(!impl_hash.is_zero(), 'Class hash cannot be zero');\n"
+" assert(impl_hash.is_non_zero(), 'Class hash cannot be zero');\n"
 " starknet::replace_class_syscall(impl_hash).unwrap_syscall();\n"
 " self.emit(Event::Upgraded(Upgraded { implementation: "
 "impl_hash }))\n"
@@ -7936,7 +7936,7 @@ msgstr ""
 " impl UpgradeableContract of super::IUpgradeableContract<ContractState> "
 "{\n"
 " fn upgrade(ref self: ContractState, impl_hash: ClassHash) {\n"
-" assert(!impl_hash.is_zero(), 'Class hash cannot be zero');\n"
+" assert(impl_hash.is_non_zero(), 'Class hash cannot be zero');\n"
 " starknet::replace_class_syscall(impl_hash).unwrap_syscall();\n"
 " self.emit(Event::Upgraded(Upgraded { implementation: "
 "impl_hash }))\n"
@@ -8481,8 +8481,8 @@ msgid ""
 " recipient: ContractAddress,\n"
 " amount: felt252\n"
 " ) {\n"
-" assert(!sender.is_zero(), Errors::TRANSFER_FROM_ZERO);\n"
-" assert(!recipient.is_zero(), Errors::TRANSFER_TO_ZERO);\n"
+" assert(sender.is_non_zero(), Errors::TRANSFER_FROM_ZERO);\n"
+" assert(recipient.is_non_zero(), Errors::TRANSFER_TO_ZERO);\n"
 " self.balances.write(sender, self.balances.read(sender) - "
 "amount);\n"
 " self.balances.write(recipient, self.balances.read(recipient) + "
@@ -8507,14 +8507,14 @@ msgid ""
 " spender: ContractAddress,\n"
 " amount: felt252\n"
 " ) {\n"
-" assert(!spender.is_zero(), Errors::APPROVE_TO_ZERO);\n"
+" assert(spender.is_non_zero(), Errors::APPROVE_TO_ZERO);\n"
 " self.allowances.write((owner, spender), amount);\n"
 " self.emit(Approval { owner, spender, value: amount });\n"
 " }\n"
 "\n"
 " fn mint(ref self: ContractState, recipient: ContractAddress, amount: "
 "felt252) {\n"
-" assert(!recipient.is_zero(), Errors::MINT_TO_ZERO);\n"
+" assert(recipient.is_non_zero(), Errors::MINT_TO_ZERO);\n"
 " let supply = self.total_supply.read() + amount; // What can go "
 "wrong here?\n"
 " self.total_supply.write(supply);\n"
@@ -8682,8 +8682,8 @@ msgstr ""
 " recipient: ContractAddress,\n"
 " amount: felt252\n"
 " ) {\n"
-" assert(!sender.is_zero(), Errors::TRANSFER_FROM_ZERO);\n"
-" assert(!recipient.is_zero(), Errors::TRANSFER_TO_ZERO);\n"
+" assert(sender.is_non_zero(), Errors::TRANSFER_FROM_ZERO);\n"
+" assert(recipient.is_non_zero(), Errors::TRANSFER_TO_ZERO);\n"
 " self.balances.write(sender, self.balances.read(sender) - "
 "amount);\n"
 " self.balances.write(recipient, self.balances.read(recipient) + "
@@ -8708,14 +8708,14 @@ msgstr ""
 " spender: ContractAddress,\n"
 " amount: felt252\n"
 " ) {\n"
-" assert(!spender.is_zero(), Errors::APPROVE_TO_ZERO);\n"
+" assert(spender.is_non_zero(), Errors::APPROVE_TO_ZERO);\n"
 " self.allowances.write((owner, spender), amount);\n"
 " self.emit(Approval { owner, spender, value: amount });\n"
 " }\n"
 "\n"
 " fn mint(ref self: ContractState, recipient: ContractAddress, amount: "
 "felt252) {\n"
-" assert(!recipient.is_zero(), Errors::MINT_TO_ZERO);\n"
+" assert(recipient.is_non_zero(), Errors::MINT_TO_ZERO);\n"
 " let supply = self.total_supply.read() + amount; // What can go "
 "wrong here?\n"
 " self.total_supply.write(supply);\n"

po/zh-cn.po

@@ -4269,7 +4269,7 @@ msgid ""
 " #[abi(embed_v0)]\n"
 " impl UpgradeableContract of super::IUpgradeableContract<ContractState> {\n"
 " fn upgrade(ref self: ContractState, impl_hash: ClassHash) {\n"
-" assert(!impl_hash.is_zero(), 'Class hash cannot be zero');\n"
+" assert(impl_hash.is_non_zero(), 'Class hash cannot be zero');\n"
 " starknet::replace_class_syscall(impl_hash).unwrap_syscall();\n"
 " self.emit(Event::Upgraded(Upgraded { implementation: "
 "impl_hash }))\n"
@@ -4314,7 +4314,7 @@ msgstr ""
 " #[abi(embed_v0)]\n"
 " impl UpgradeableContract of super::IUpgradeableContract<ContractState> {\n"
 " fn upgrade(ref self: ContractState, impl_hash: ClassHash) {\n"
-" assert(!impl_hash.is_zero(), 'Class hash cannot be zero');\n"
+" assert(impl_hash.is_non_zero(), 'Class hash cannot be zero');\n"
 " starknet::replace_class_syscall(impl_hash).unwrap_syscall();\n"
 " self.emit(Event::Upgraded(Upgraded { implementation: "
 "impl_hash }))\n"
@@ -4377,7 +4377,7 @@ msgid ""
 " #[abi(embed_v0)]\n"
 " impl UpgradeableContract of super::IUpgradeableContract<ContractState> {\n"
 " fn upgrade(ref self: ContractState, impl_hash: ClassHash) {\n"
-" assert(!impl_hash.is_zero(), 'Class hash cannot be zero');\n"
+" assert(impl_hash.is_non_zero(), 'Class hash cannot be zero');\n"
 " starknet::replace_class_syscall(impl_hash).unwrap_syscall();\n"
 " self.emit(Event::Upgraded(Upgraded { implementation: "
 "impl_hash }))\n"
@@ -4422,7 +4422,7 @@ msgstr ""
 " #[abi(embed_v0)]\n"
 " impl UpgradeableContract of super::IUpgradeableContract<ContractState> {\n"
 " fn upgrade(ref self: ContractState, impl_hash: ClassHash) {\n"
-" assert(!impl_hash.is_zero(), 'Class hash cannot be zero');\n"
+" assert(impl_hash.is_non_zero(), 'Class hash cannot be zero');\n"
 " starknet::replace_class_syscall(impl_hash).unwrap_syscall();\n"
 " self.emit(Event::Upgraded(Upgraded { implementation: "
 "impl_hash }))\n"
@@ -4961,8 +4961,8 @@ msgid ""
 " recipient: ContractAddress,\n"
 " amount: felt252\n"
 " ) {\n"
-" assert(!sender.is_zero(), Errors::TRANSFER_FROM_ZERO);\n"
-" assert(!recipient.is_zero(), Errors::TRANSFER_TO_ZERO);\n"
+" assert(sender.is_non_zero(), Errors::TRANSFER_FROM_ZERO);\n"
+" assert(recipient.is_non_zero(), Errors::TRANSFER_TO_ZERO);\n"
 " self.balances.write(sender, self.balances.read(sender) - "
 "amount);\n"
 " self.balances.write(recipient, self.balances.read(recipient) + "
@@ -4987,14 +4987,14 @@ msgid ""
 " spender: ContractAddress,\n"
 " amount: felt252\n"
 " ) {\n"
-" assert(!spender.is_zero(), Errors::APPROVE_TO_ZERO);\n"
+" assert(spender.is_non_zero(), Errors::APPROVE_TO_ZERO);\n"
 " self.allowances.write((owner, spender), amount);\n"
 " self.emit(Approval { owner, spender, value: amount });\n"
 " }\n"
 "\n"
 " fn mint(ref self: ContractState, recipient: ContractAddress, amount: "
 "felt252) {\n"
-" assert(!recipient.is_zero(), Errors::MINT_TO_ZERO);\n"
+" assert(recipient.is_non_zero(), Errors::MINT_TO_ZERO);\n"
 " let supply = self.total_supply.read() + amount; // What can go "
 "wrong here?\n"
 " self.total_supply.write(supply);\n"
@@ -5162,8 +5162,8 @@ msgstr ""
 " recipient: ContractAddress,\n"
 " amount: felt252\n"
 " ) {\n"
-" assert(!sender.is_zero(), Errors::TRANSFER_FROM_ZERO);\n"
-" assert(!recipient.is_zero(), Errors::TRANSFER_TO_ZERO);\n"
+" assert(sender.is_non_zero(), Errors::TRANSFER_FROM_ZERO);\n"
+" assert(recipient.is_non_zero(), Errors::TRANSFER_TO_ZERO);\n"
 " self.balances.write(sender, self.balances.read(sender) - "
 "amount);\n"
 " self.balances.write(recipient, self.balances.read(recipient) + "
@@ -5188,14 +5188,14 @@ msgstr ""
 " spender: ContractAddress,\n"
 " amount: felt252\n"
 " ) {\n"
-" assert(!spender.is_zero(), Errors::APPROVE_TO_ZERO);\n"
+" assert(spender.is_non_zero(), Errors::APPROVE_TO_ZERO);\n"
 " self.allowances.write((owner, spender), amount);\n"
 " self.emit(Approval { owner, spender, value: amount });\n"
 " }\n"
 "\n"
 " fn mint(ref self: ContractState, recipient: ContractAddress, amount: "
 "felt252) {\n"
-" assert(!recipient.is_zero(), Errors::MINT_TO_ZERO);\n"
+" assert(recipient.is_non_zero(), Errors::MINT_TO_ZERO);\n"
 " let supply = self.total_supply.read() + amount; // What can go "
 "wrong here?\n"
 " self.total_supply.write(supply);\n"

src/ch01/constant-product-amm.md

@@ -1,6 +1,6 @@
 # Constant Product AMM
 
-This is the Cairo adaptation of the [Solidity by example Constant Product AMM](https://solidity-by-example.org/defi/constant-product-amm/).
+This is the Cairo adaptation of the [Solidity by Example - Constant Product AMM](https://solidity-by-example.org/defi/constant-product-amm/).
 
 ```rust
 {{#include ../../listings/applications/constant_product_amm/src/contracts.cairo:ConstantProductAmmContract}}

src/ch01/erc20.md

@@ -2,13 +2,13 @@
 
 Contracts that follow the [ERC20 Standard](https://eips.ethereum.org/EIPS/eip-20) are called ERC20 tokens. They are used to represent fungible assets.
 
-To create an ERC20 conctract, it must implement the following interface:
+To create an ERC20 contract, it must implement the following interface:
 
 ```rust
 {{#include ../../listings/applications/erc20/src/token.cairo:interface}}
 ```
 
-In Starknet, function names should be written in *snake_case*. This is not the case in Solidity, where function names are written in *camelCase*.
+In Starknet, function names should be written in _snake_case_. This is not the case in Solidity, where function names are written in _camelCase_.
 The Starknet ERC20 interface is therefore slightly different from the Solidity ERC20 interface.
 
 Here's an implementation of the ERC20 interface in Cairo:

src/ch01/simple_vault.md

@@ -1,11 +1,11 @@
 # Simple Defi Vault
 
-This is the Cairo adaptation of the [Solidity by example Vault](https://solidity-by-example.org/defi/vault/).
+This is the Cairo adaptation of the [Solidity by Example - Vault](https://solidity-by-example.org/defi/vault/).
 Here's how it works:
 
 - When a user deposits a token, the contract calculates the amount of shares to mint.
 
-- When a user withdraws, the contract burns their shares, calculates the yield, and withdraw both the yield and the initial amount of token deposited.
+- When a user withdraws, the contract burns their shares, calculates the yield, and withdraws both the yield and the initial amount of tokens deposited.
 
 ```rust
 {{#include ../../listings/applications/simple_vault/src/simple_vault.cairo}}

src/ch01/staking.md

@@ -5,27 +5,29 @@ The following staking contract is designed to allow users to stake tokens in exc
 ### Key Features:
 
 1. Token staking and unstaking:
- - Users can stake a ERC20 token, specified at deployment.
- - Users can withdraw their staked tokens at any time.
+
+ - Users can stake an ERC20 token, specified at deployment.
+ - Users can withdraw their staked tokens at any time.
 
 2. Reward calculation and distribution:
- - The rewards are distributed as an ERC20, also specified at deployment (can be different from the staking token).
- - Rewards are calculated based on the duration of staking and the amount the user staked relative to the total staked amount by all users.
- - A user’s reward accumulates over time up until the reward period's end and can be claimed anytime by the user.
+
+ - The rewards are distributed as an ERC20, also specified at deployment (can be different from the staking token).
+ - Rewards are calculated based on the duration of staking and the amount the user staked relative to the total staked amount by all users.
+ - A user’s reward accumulates over time up until the reward period's end and can be claimed anytime by the user.
 
 3. Dynamic reward rates:
- - The reward rate is determined by the total amount of reward tokens over a set period (duration).
- - The reward rate can be adjusted during the rewards period if new rewards are added before the current reward period finishes.
- - Even after a reward period finishes, a new reward duration and new rewards can be setup if desired.
+
+ - The reward rate is determined by the total amount of reward tokens over a set period (duration).
+ - The reward rate can be adjusted during the rewards period if new rewards are added before the current reward period finishes.
+ - Even after a reward period finishes, a new reward duration and new rewards can be set up if desired.
 
 4. Ownership and administration:
-  - Only the owner of the contract can set the rewards amount and duration.
+ - Only the owner of the contract can set the rewards amount and duration.
 
 > The reward mechanism ensures that rewards are distributed fairly based on the amount and duration of tokens staked by each user.
 
-The following implementation is the Cairo adaptation of the [Solidity by example Staking Rewards contract](https://solidity-by-example.org/defi/staking-rewards/), with a little adaptation allowing to keep track of the amount of total distributed reward tokens in order to emit an event when the remaining reward tokens amount falls down to 0.
+The following implementation is the Cairo adaptation of the [Solidity by Example - Staking Rewards contract](https://solidity-by-example.org/defi/staking-rewards/). It includes a small adaptation to keep track of the amount of total distributed reward tokens and emit an event when the remaining reward token amount reaches 0.
 
 ```rust
 {{#include ../../listings/applications/staking/src/contract.cairo}}
 ```
-