ETH Singapore 2023 Intro to Vyper

demo.vy

# @version ^0.3.7

# Declare an enum with three members
enum Permission:
    EXECUTE    # 1
    WRITE      # 2
    READ       # 4

# Declare a public storage mapping of address to Permission enum
permissions: public(HashMap[address, Permission])

# Constructor
# For illustration only
@external
def __init__():
    pass

# External functions that can modify state
@external
def grant_permission(a: address, p: Permission):
    self.permissions[a] |= p
    
@external
def revoke_permission(a: address, p: Permission):
    self.permissions[a] &= ~p
    
# External functions that can read from state but not modify it
@external
@view
def can_read(a: address) -> bool:
    return Permission.READ in self.permissions[a]

@external
@view
def can_write(a: address) -> bool:
    return Permission.WRITE in self.permissions[a]

@external
@view
def can_execute(a: address) -> bool:
    return Permission.EXECUTE in self.permissions[a]

@external
@view
def get_uint256(a: address) -> uint256:
    return convert(self.permissions[a], uint256)

thanks!

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