Fix event param in erc20 and erc721 (#226)

* fix _from param

* replace _from with from_

* update _from in docs

docs/ERC20.md

@@ -313,7 +313,7 @@ success: felt
 ### Events
 
 ```jsx
-func Transfer(_from: felt, to: felt, value: Uint256):
+func Transfer(from_: felt, to: felt, value: Uint256):
 end
 
 func Approval(owner: felt, spender: felt, value: Uint256):
@@ -322,14 +322,14 @@ end
 
 #### `Transfer (event)`
 
-Emitted when `value` tokens are moved from one account (`_from`) to another (`to`). 
+Emitted when `value` tokens are moved from one account (`from_`) to another (`to`). 
 
 Note that `value` may be zero.
 
 Parameters:
 
 ```jsx
-_from: felt
+from_: felt
 to: felt
 value: Uint256
 ```

docs/ERC721.md

@@ -67,14 +67,14 @@ namespace IERC721:
     end
 
     func safeTransferFrom(
-        _from: felt, 
+        from_: felt, 
         to: felt, 
         tokenId: Uint256, 
         data_len: felt,
         data: felt*
     ):
 
-    func transferFrom(_from: felt, to: felt, tokenId: Uint256):
+    func transferFrom(from_: felt, to: felt, tokenId: Uint256):
     end
 
     func approve(approved: felt, tokenId: Uint256):
@@ -219,7 +219,7 @@ Interface for any contract that wants to support safeTransfers from ERC721 asset
 namespace IERC721_Receiver:
     func onERC721Received(
         operator: felt,
-        _from: felt,
+        from_: felt,
         tokenId: Uint256,
         data_len: felt
         data: felt*
@@ -354,15 +354,15 @@ func ownerOf(tokenId: Uint256) -> (owner: felt):
 end
 
 func safeTransferFrom(
-        _from: felt, 
+        from_: felt, 
         to: felt, 
         tokenId: Uint256, 
         data_len: felt,
         data: felt*
     ):
 end
 
-func transferFrom(_from: felt, to: felt, tokenId: Uint256):
+func transferFrom(from_: felt, to: felt, tokenId: Uint256):
     end
 
 func approve(approved: felt, tokenId: Uint256):
@@ -413,14 +413,14 @@ owner: felt
 
 #### `safeTransferFrom`
 
-Safely transfers `tokenId` token from `_from` to `to`, checking first that contract recipients are aware of the ERC721 protocol to prevent tokens from being forever locked. For information regarding how contracts communicate their awareness of the ERC721 protocol, see [ERC721Received](#erc721received).
+Safely transfers `tokenId` token from `from_` to `to`, checking first that contract recipients are aware of the ERC721 protocol to prevent tokens from being forever locked. For information regarding how contracts communicate their awareness of the ERC721 protocol, see [ERC721Received](#erc721received).
 
 Emits a [Transfer](#-Transfer-(event)-) event.
 
 Parameters:
 
 ```jsx
-_from: felt
+from_: felt
 to: felt
 tokenId: Uint256
 data_len: felt
@@ -433,7 +433,7 @@ None.
 
 #### `transferFrom`
 
-Transfers `tokenId` token from `_from` to `to`.
+Transfers `tokenId` token from `from_` to `to`.
 
 > Note that this function should be used instead of `safeTransferFrom` to transfer tokens. Exercise caution as tokens sent to a contract that does not support ERC721 can be lost forever.
 
@@ -442,7 +442,7 @@ Emits a [Transfer](#-Transfer-(event)-) event.
 Parameters:
 
 ```jsx
-_from: felt
+from_: felt
 to: felt
 tokenId: Uint256
 ```
@@ -545,12 +545,12 @@ approved: felt
 
 #### `Transfer (Event)`
 
-Emitted when `tokenId` token is transferred from `_from` to `to`.
+Emitted when `tokenId` token is transferred from `from_` to `to`.
 
 Parameters:
 
 ```jsx
-_from: felt
+from_: felt
 to: felt
 tokenId: Uint256
 ```
@@ -679,7 +679,7 @@ tokenId: Uint256
 ```jsx
 func onERC721Received(
         operator: felt, 
-        _from: felt, 
+        from_: felt, 
         tokenId: Uint256, 
         data_len: felt
         data: felt*
@@ -689,14 +689,14 @@ end
 
 #### `onERC721Received`
 
-Whenever an IERC721 `tokenId` token is transferred to this non-account contract via `safeTransferFrom` by `operator` from `_from`, this function is called.
+Whenever an IERC721 `tokenId` token is transferred to this non-account contract via `safeTransferFrom` by `operator` from `from_`, this function is called.
 
 
 Parameters:
 
 ```jsx
 operator: felt
-_from: felt
+from_: felt
 tokenId: Uint256
 data_len: felt
 data: felt*

src/openzeppelin/token/erc20/library.cairo

@@ -17,7 +17,7 @@ from openzeppelin.utils.constants import TRUE, FALSE, UINT8_MAX
 #
 
 @event
-func Transfer(_from: felt, to: felt, value: Uint256):
+func Transfer(from_: felt, to: felt, value: Uint256):
 end
 
 @event

src/openzeppelin/token/erc721/ERC721_Mintable_Burnable.cairo

@@ -167,11 +167,11 @@ func transferFrom{
         syscall_ptr: felt*, 
         range_check_ptr
     }(
-        _from: felt, 
+        from_: felt, 
         to: felt, 
         tokenId: Uint256
     ):
-    ERC721_transferFrom(_from, to, tokenId)
+    ERC721_transferFrom(from_, to, tokenId)
     return ()
 end
 
@@ -181,13 +181,13 @@ func safeTransferFrom{
         syscall_ptr: felt*, 
         range_check_ptr
     }(
-        _from: felt, 
+        from_: felt, 
         to: felt, 
         tokenId: Uint256,
         data_len: felt, 
         data: felt*
     ):
-    ERC721_safeTransferFrom(_from, to, tokenId, data_len, data)
+    ERC721_safeTransferFrom(from_, to, tokenId, data_len, data)
     return ()
 end
 

src/openzeppelin/token/erc721/ERC721_Mintable_Pausable.cairo

@@ -184,12 +184,12 @@ func transferFrom{
         syscall_ptr: felt*, 
         range_check_ptr
     }(
-        _from: felt, 
+        from_: felt, 
         to: felt, 
         tokenId: Uint256
     ):
     Pausable_when_not_paused()
-    ERC721_transferFrom(_from, to, tokenId)
+    ERC721_transferFrom(from_, to, tokenId)
     return ()
 end
 
@@ -199,14 +199,14 @@ func safeTransferFrom{
         syscall_ptr: felt*, 
         range_check_ptr
     }(
-        _from: felt, 
+        from_: felt, 
         to: felt, 
         tokenId: Uint256,
         data_len: felt, 
         data: felt*
     ):
     Pausable_when_not_paused()
-    ERC721_safeTransferFrom(_from, to, tokenId, data_len, data)
+    ERC721_safeTransferFrom(from_, to, tokenId, data_len, data)
     return ()
 end
 

src/openzeppelin/token/erc721/interfaces/IERC721.cairo

@@ -16,15 +16,15 @@ namespace IERC721:
     end
 
     func safeTransferFrom(
-            _from: felt, 
+            from_: felt, 
             to: felt, 
             tokenId: Uint256, 
             data_len: felt,
             data: felt*
         ):
     end
 
-    func transferFrom(_from: felt, to: felt, tokenId: Uint256):
+    func transferFrom(from_: felt, to: felt, tokenId: Uint256):
     end
 
     func approve(approved: felt, tokenId: Uint256):

src/openzeppelin/token/erc721/interfaces/IERC721_Receiver.cairo

@@ -9,7 +9,7 @@ from starkware.cairo.common.uint256 import Uint256
 namespace IERC721_Receiver:
     func onERC721Received(
         operator: felt,
-        _from: felt,
+        from_: felt,
         tokenId: Uint256,
         data_len: felt,
         data: felt*

src/openzeppelin/token/erc721/library.cairo

@@ -27,7 +27,7 @@ from openzeppelin.utils.constants import TRUE, FALSE
 #
 
 @event
-func Transfer(_from: felt, to: felt, tokenId: Uint256):
+func Transfer(from_: felt, to: felt, tokenId: Uint256):
 end
 
 @event
@@ -255,7 +255,7 @@ func ERC721_transferFrom{
         pedersen_ptr: HashBuiltin*,
         syscall_ptr: felt*,
         range_check_ptr
-    }(_from: felt, to: felt, token_id: Uint256):
+    }(from_: felt, to: felt, token_id: Uint256):
     alloc_locals
     with_attr error_message("ERC721: token_id is not a valid Uint256"):
         uint256_check(token_id)
@@ -271,7 +271,7 @@ func ERC721_transferFrom{
     # meaning that a*0==0 for all a in the field,
     # therefore a*b==0 implies that at least one of a,b is zero in the field
 
-    _transfer(_from, to, token_id)
+    _transfer(from_, to, token_id)
     return ()
 end
 
@@ -280,7 +280,7 @@ func ERC721_safeTransferFrom{
         syscall_ptr: felt*,
         range_check_ptr
     }(
-        _from: felt,
+        from_: felt,
         to: felt,
         token_id: Uint256,
         data_len: felt,
@@ -301,7 +301,7 @@ func ERC721_safeTransferFrom{
     # meaning that a*0==0 for all a in the field,
     # therefore a*b==0 implies that at least one of a,b is zero in the field
 
-    _safe_transfer(_from, to, token_id, data_len, data)
+    _safe_transfer(from_, to, token_id, data_len, data)
     return ()
 end
 
@@ -477,11 +477,11 @@ func _transfer{
         syscall_ptr: felt*,
         pedersen_ptr: HashBuiltin*,
         range_check_ptr
-    }(_from: felt, to: felt, token_id: Uint256):
-    # ownerOf ensures '_from' is not the zero address
+    }(from_: felt, to: felt, token_id: Uint256):
+    # ownerOf ensures 'from_' is not the zero address
     let (_ownerOf) = ERC721_ownerOf(token_id)
     with_attr error_message("ERC721: transfer from incorrect owner"):
-        assert _ownerOf = _from
+        assert _ownerOf = from_
     end
 
     with_attr error_message("ERC721: cannot transfer to the zero address"):
@@ -492,9 +492,9 @@ func _transfer{
     _approve(0, token_id)
 
     # Decrease owner balance
-    let (owner_bal) = ERC721_balances.read(_from)
+    let (owner_bal) = ERC721_balances.read(from_)
     let (new_balance: Uint256) = uint256_checked_sub_le(owner_bal, Uint256(1, 0))
-    ERC721_balances.write(_from, new_balance)
+    ERC721_balances.write(from_, new_balance)
 
     # Increase receiver balance
     let (receiver_bal) = ERC721_balances.read(to)
@@ -503,7 +503,7 @@ func _transfer{
 
     # Update token_id owner
     ERC721_owners.write(token_id, to)
-    Transfer.emit(_from, to, token_id)
+    Transfer.emit(from_, to, token_id)
     return ()
 end
 
@@ -512,15 +512,15 @@ func _safe_transfer{
         pedersen_ptr: HashBuiltin*,
         range_check_ptr
     }(
-        _from: felt,
+        from_: felt,
         to: felt,
         token_id: Uint256,
         data_len: felt,
         data: felt*
     ):
-    _transfer(_from, to, token_id)
+    _transfer(from_, to, token_id)
 
-    let (success) = _check_onERC721Received(_from, to, token_id, data_len, data)
+    let (success) = _check_onERC721Received(from_, to, token_id, data_len, data)
     with_attr error_message("ERC721: transfer to non ERC721Receiver implementer"):
         assert_not_zero(success)
     end
@@ -532,7 +532,7 @@ func _check_onERC721Received{
         pedersen_ptr: HashBuiltin*,
         range_check_ptr
     }(
-        _from: felt,
+        from_: felt,
         to: felt,
         token_id: Uint256,
         data_len: felt,
@@ -545,7 +545,7 @@ func _check_onERC721Received{
         let (selector) = IERC721_Receiver.onERC721Received(
             to,
             caller,
-            _from,
+            from_,
             token_id,
             data_len,
             data

src/openzeppelin/token/erc721/utils/ERC721_Holder.cairo

@@ -14,7 +14,7 @@ from openzeppelin.introspection.ERC165 import (
 @view
 func onERC721Received(
         operator: felt,
-        _from: felt,
+        from_: felt,
         tokenId: Uint256,
         data_len: felt,
         data: felt*