Structuring code

Libs and snippets for structuring code properly

dataclasses

dataclasses for easy data classes with attributes which may be const

@dataclass(order=True, frozen=True)
class Command:
    command: str
    arguments: List[str]

def createComm(comm, *others) -> Command:
    return Command(comm, others)

def testFeatures():
    cmd1 = createComm(*"go fetch the ball".split())
    cmd2 = createComm(*"come get some food".split())
    print(cmd1, cmd2, sep="\t")
    print(cmd1>cmd2)
    
def testFreeze():
    cmd, *rest = "what does the fox say".split()
    test = Command(cmd, rest)
    test.command = "other"
    print(test.command, test.arguments)

#if __name__ == "__main__":
#    main()

Good clean printing description plus order=True allows for comparisson

testFeatures()

Command(command='go', arguments=('fetch', 'the', 'ball'))   Command(command='come', arguments=('get', 'some', 'food'))
True

Here we can see the frozen=True rises and error when we try to reset an attribute

try:
    testFreeze()
except FrozenInstanceError as e:
    print(e.__class__.__name__, ": ", e)

FrozenInstanceError :  cannot assign to field 'command'

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typing

typing has to be called for type hintting on callables and lists.

• Not on newer python, apparently

def uDictRandKey(frand: Callable[[List[str],int],List[int]]=np.random.choice,
                 base: str=letters, qty: int=1) -> List[str]:
    keys = []
    numChars = 1
    baseSize = len(set(base))
    while (qty//(baseSize**numChars)): numChars+=1
    
    return frand([*base], size=qty)
np.random.choice([*letters], size=10)

array(['a', 't', 'e', 'r', 'm', 'n', 'e', 'v', 'e', 'i'], dtype='<U1')

uDictRandKey(np.random.choice)

array(['d'], dtype='<U1')

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Protocol

Protocol class implements interfaces in python. “Duck-typing”: if it has the right methods, it is the right type

class call(Protocol):
    def talk():
        ...
    def listen():
        ...
        
class msg(Protocol):
    def write():
        ...
    def read():
        ...
        
class extro:
    def __init__(self, name="Beeblebrot"):
        self.name = name
    def talk(self):
        print(f"{self.name} is talking..")
    def listen(self):
        print(f"{self.name} is not listening..")
    def read(self):
        print(f"{self.name} is not reading..")
    def write(self):
        print(f"{self.name} is writing..")
        
class intro:
    def __init__(self, name="Arthur"):
        self.name = name
    def talk(self):
        print(f"{self.name} is not talking..")
    def listen(self):
        print(f"{self.name} is listening..")
    def read(self):
        print(f"{self.name} is reading..")
    def write(self):
        print(f"{self.name} is not writing..")
        
def phonecall(person1: call, person2: call):
    person1.talk()
    person2.listen()
    person2.talk()
    person1.listen()
    
def textchat(person1: msg, person2: msg):
    person1.write()
    person2.read()
    person2.write()
    person1.read()
    
p1, p2 = extro(), intro()
phonecall(p1,p2)
textchat(p1,p2)

Beeblebrot is talking..
Arthur is listening..
Arthur is not talking..
Beeblebrot is not listening..
Beeblebrot is writing..
Arthur is reading..
Arthur is not writing..
Beeblebrot is not reading..

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partial

partial decorator/class allows for parameter pre setting in functions

def myprint(toPrint,toPrint2):
    print(toPrint,toPrint2)

otherprint = partial(myprint, toPrint2="42")
otherprint("what is 6x8? ")
otherprint("what is 6x7? ")

what is 6x8?  42
what is 6x7?  42

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ABC and abstractmethod

ABC class inheriting and abstractmethod decorator implements abstract classes in python

class absClass(ABC):
    @abstractmethod
    def aMethod(self):
        '''this method does this'''
    
    @abstractmethod
    def bMethod(self):
        '''this method does that'''
        
class concreteClass(absClass):
    
    def aMethod(self):
        print('this method does this')
        return self
        
    def bMethod(self):
        print('this method does that')
        return self
        
def testABC(obj: absClass):
    obj.aMethod().bMethod()
    
testABC(concreteClass())

this method does this
this method does that

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