Take these examples:

>>> raise(BaseException())
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
BaseException

>>> raise BaseException()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
BaseException

Recall this aphorism:

There should be one-- and preferably only one --obvious way to do it.

If raise is a keyword, why is it syntactically allowed to be viewed as being invoked like a function?

There are some other keywords as well which allow attached parenthesis. Isn't it confusing?

CodePudding user response：

Putting parentheses around something just makes it a parenthesized value; it does not magically make it a function call.

1 is the same as (1), therefore return 1 is the same as return (1).

But it's not a function call.

CodePudding user response：

You can add parentheses around any expression, it’s just that the parentheses are required for function calls.

print 123 # error
print(123) # ok
print((123)) # extra parentheses ok

And

raise BaseException() # ok
raise (BaseException()) # extra parentheses ok

CodePudding user response：

Using bare parenthesis would do nothing to the element.

Therefore there is no difference between with and without parenthesis:

>>> (BaseException())
BaseException()
>>> BaseException()
BaseException()
>>> 

Only if you add a comma would make it a tuple.

So in short:

raise is a keyword!

CodePudding user response：

It's not being invoked as a function, you simply have extra parenthesis around the exception object. Consider:

ex = (BaseException())
raise ex

Additionally, your second example provides a counterargument. If raise was not a keyword, that example would fail.