Boris Borcic writes:
I must admit I wasn't expecting the discussion to rely so quickly on involving my character.
Some people have natural talent for a particular kind of design, some don't. If one doesn't, it's no big deal, s/he still can contribute, even to design---but coming up with original ideas is likely to waste her/his time and that of others. (I don't say it's impossible to develop it as a skill, but it would take real work.)
Why not take Guido's comment literally, "*if* you don't have it," and think about the "litmus test" he described? (Ie, think about why this proposal is unattractive.) Of course, there is an implication that you *don't* have it, but it will be better all around if you ignore that implication, and leave it an open question as long as you want to contribute in this way.
In conclusion, I guess I'm warranted to take this to mean "we can dream up no appropriate syntax".
I wouldn't say "impossible". However, the senior developers who have spoken up clearly think that your proposal (a) is not an improvement over x = f(x) in most use cases (and IMO often would be worse, because x += y expresses accumulation of y, while x = y expresses replacement) and (b) seems to have very few, if any, appropriate use cases. So "why bother?" is the message.
PS,FYI : a notation borne from letting parens live independent lives, and indeed could fly http://en.wikipedia.org/wiki/Bra-ket_notation
As I understand it, the bra-ket notation arose in physics because both the bra part and the ket part make sense as operators, but only in the lefthand role for the bra, and righthand role for the ket. So they don't really live independent lives, any more than the dx and the dy do in conventional calculus.
However, in your syntax you do (c) lose the kind of implied symmetry that the bra-ket and infinitesimal notations have. You could "fix" that by using the notation "apply-and-assign" x ()= f, but that syntax already has a meaning in python, and runs even more forcefully into STeVe's criticism that parens are a postfix operator, not infix.
Note that I myself can come up with criticisms like (a), (b), and (c) but to the best of my knowledge I've never invented any useful syntax.<wink>