CODEWITHSUNDEEP
pythonpython-decorators
Extreme112
Extreme112

Reputation: 95

Converting decorators to their implementation code

I'm learning about decorators and found this useful thread that really helped me a lot. How to make a chain of function decorators?

Based on what I understand, decorators are just syntactic sugar. However I'm having trouble converting from the syntactic sugar code to non-syntactic sugar code.

# Decorators
def addBold(func):
    def wrapper(*arg1):
        print("Bold Added")
        return '<b>' + func(*arg1) + '</b>'
    return wrapper

def addItalic(func):
    def wrapper(*arg1):
        print("Italic Added")
        return '<i>' + func(*arg1) + '</i>'
    return wrapper

This code works:

@addBold
def getHTMLCode(passedText):
    return passedText

newVar = getHTMLCode('Hello')
print(newVar)
# outputs: Bold Added <b>Hello</b>

I tried converting to non-syntactic sugar code, but this not work (TypeError: 'str' object is not callable):

def getHTMLCode(passedText):
    return passedText

newVar = addBold(getHTMLCode('Hello'))  # returns wrapper
newVar()

What does the working code (second block) look like w/o the decorator syntactic sugar?

Upvotes: 0

Views: 37

Answers (1)

Ross Ridge
Ross Ridge

Reputation: 39581

You need to pass the function you want wrapped to the decorator function and then call the returned wrapper with the arguments:

wrapped_getHTMLCode = addBold(getHTMLCode)
wrapped_getHTMLCode('Hello')

Notice how wrapped_getHTMLCode works like the decorated version of getHTMLCode. You call it with the string you want bolded, and it returns the string with HTML bold markup around it.

Upvotes: 2

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