syntax question for defun

[David Elson <delson@greatalpha.com>]

Hello. I have been using emacs for ... a while.

For questions, I have often browsed and browsed (i.e. googled) and ... 
and usually find a good explanation. But sometimes I don't find an 
answer, even when it is staring right at me.

My question:

To emulate something akin to the PL1/C/C++ arrow notation, I have used:

*(defun -> (object method &rest args) ...)*

and it works.

*Is this valid elisp/lisp?*

If it works only coincidentally, then it might break in the future, when 
a pressing emacs issue is resolved in a manner that requires plugging 
this "loophole".

If it is formally valid, where does it document the level of flexibility 
that allows this syntax?

If it is not formally valid, then why does it work coincidentally?

I'd like to enhance/use this code, but I hesitate due to this question.

Thanks in advance?

-David