Rule of order for dot operators?

[Steven D'Aprano]

On Mon, 8 Jun 2015 09:21 pm, Albert van der Horst wrote:


> Why is "slug.title" a valid decomposition of the total string>
> (Or is it?)

I'm afraid I don't understand the question.


> What is the ()-brackets doing? Does it force the execution of title,
> which gives something to be dotted onto slug etc. See below.

slug.title looks up an attribute called "title" attached to the object
called "slug". In this case, slug is a string, so slug.title finds the
string title method:


py> slug = "hello"
py> slug.title
<built-in method title of str object at 0xb7b036e0>


Then the round brackets (parentheses) calls that method with no arguments,
which returns a new string:

py> slug.title()
'Hello'



> I interpreted the question as about the associative of the
> dot operator.

Technically, dot is not an operator. I believe that the docs call it a
delimiter, but in once sense it is more than that because it also performs
an attribute lookup. 

In any case, the order of applying dots is *strictly* left-to-right.




-- 
Steven