Thanks for your feedback. A few comments:
> I do not consider these two things conceptually equivalent. In Python the identifier ('a' in this case) is just label to the value
I used APL professionally for about ten years. None of your objections ring true. A simple example is had from mathematics. The integral symbol conveys and represents a concept. Once the practitioner is introduced to the definition of that symbol, what it means, he or she uses it. It really is a simple as that, this is how our brains work. That's how you recognize the letter "A" as to correspond to a sound and as part of words. This is how, in languages such as Chinese, symbols, notation, are connected to meaning. It is powerful and extremely effective.
The use of notation as a tool for thought is a powerful concept that transcends programming. Mathematics is a simple example. So is music. Musical notation allows the expression of ideas and massively complex works as well as their creation. In electronics we have circuit diagrams, which are not literal depictions of circuits but rather a notation to represent them, to think about them, to invent them.
The future of computing, in my opinion, must move away --perhaps not entirely-- from ASCII-based typing of words. If we want to be able to express and think about programming at a higher level we need to develop a notation. As AI and ML evolve this might become more and more critical.
APL, sadly, was too early. Machines of the day were literally inadequate in almost every respect. It is amazing that the language went as far as it did. Over 30+ years I have worked with over a dozen languages, ranging from low level machine code through Forth, APL, Lisp, C, C++, Objective-C, and all the "modern" languages such as Python, JS, PHP, etc. Programming with APL is a very different experience. Your mind works differently. I can only equate it to writing orchestral scores in the sense that the symbols represent very complex textures and structures that your mind learns to imagine and manipulate in real time. You think about spinning, crunching, slicing and manipulating data structures in ways you never rally think about when using any other language. Watch the videos I link to below for a taste of these ideas.
Anyhow, obviously the walrus operator is here to stay. I am not going to change anything. I personally think this is sad and a wasted opportunity to open a potentially interesting chapter in the Python story; the mild introduction of notation and a path towards evolving a richer notation over time.
> Second point, I can write := in two keystrokes, but I do not have a dedicated key for the arrow on my keyboard. Should '<--' also be an acceptable syntax?
No, using "<--" is going in the wrong direction. We want notation, not ASCII soup. One could argue even walrus is ASCII soup. Another example of ASCII soup is regex. Without real notation one introduces a huge cognitive load. Notation makes a massive difference. Any classically trained musician sees this instantly. If we replaced musical notation with sequences of two or three ASCII characters it would become an incomprehensible mess.
Typing these symbols isn't a problem at all. For example, in NARS2000, a free APL interpreter I use, the assignment operator "←" is entered simply with "Alt + [". It takes seconds to internalize this and never think about it again. If you download NARS2000 right now you will know how to enter "←" immediately because I just told you how to do it. You will also know exactly what it does. It's that simple.
The other interesting thing about notation is that it transcends language. So far all conventional programming languages have been rooted in English. I would argue there is no need for this when a programming notation, just like mathematical and musical notations have demonstrated that they transcend spoken languages. Notation isn't just a tool for thought, it adds a universal element that is impossible to achieve in any other way.
Anyhow, again, I am not going to change a thing. I am nobody in the Python world. Just thought it would be interesting to share this perspective because I truly think this was a missed opportunity. If elegance is of any importance, having two assignment operators when one can do the job, as well as evolve the language in the direction of an exciting and interesting new path is, at the very least, inelegant. I can only ascribe this to very few people involved in this process, if any, any real experience with APL. One has to use APL for real work and for at least a year or two in order for your brain to make the mental switch necessary to understand it. Just messing with it casually isn't good enough. Lots of inquisitive people have messed with it, but they don't really understand it.
Also, if you haven't seen it, these videos is very much worth watching:
Conway's Game of Life in APL
Suduku solver in APL