No, using "<--" is going in the wrong direction.  We want notation, not ASCII soup.
This distinction between notation and soup seems pretty subjective. What is the difference between soup and notation? In my mind it has a lot to do with familiarity. I watched that video about programming Conway's Game of Life in APL and it looks like an incomprehensible soup of symbols to me.

Another example of ASCII soup is regex.
That's interesting, I feel the same way. I can read most code pretty quickly, but as soon as I hit a regex it takes me 50x as long to read and I have to crack open a reference because I can never remember the notation. Luckily someone came up with a solution called verbal expressions which trade hard-to-remember symbols with easy to understand words! (though I think the Python implementation smacks of Java idioms)

I'm sure there are people who work with regular expressions on such a regular basis that they've become fluent, but when you require such deep emersion in the language before the symbols make sense to you, it's a huge barrier to entry. You can't then act all confused about why your favorite language never caught on.

Without real notation one introduces a huge cognitive load.
What is "real notation". This sounds like a no-true-Scotsman fallacy. Has everyone on this message board been communicating with fake ASCII notation this entire time?
Cognative load can come from many different places like:
1. Having to remember complex key combinations just to get your thoughts into code
2. Having to memorize what each of thousands of symbols do because there's no way to look them up in a search engine
3. Knowing no other notation system that even slightly resembles APL.
I mean, I know some esoteric mathematics, but I've never seen anything that looks even remotely like:
life{1 .3 4=+/,¯1 0 1∘.¯1 0 1∘.⌽⊂}
A big part of Python's philosophy is that you read code way more often than you write code so we should optimize readability. As one Reddit commentor put it:

APL is such a powerful language. APL is also a powerfully write-only language.

And I don't even fully agree there because it somehow manages to be almost as difficult to write.

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.

For some people. I, myself; have a learning disability and often need to look at my keyboard. The relationship between "" and "[" doesn't seem obvious at all.

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.

You know what's even simpler and requires even less cognitive load?  Typing ASCII characters...

The other interesting thing about notation is that it transcends language.

The word "notation" refers to symbols, abbreviations, and short-hand that make up domain-specific languages. Nothing about notation "transcends" language, notation is a component of language. Math is the study of patterns. Mathematical notation is what we use to write the language of patterns, to describe different patterns and communicate ideas about patterns. There used to be different mathematical languages based on culture, just like spoken languages. There's no magical property that made Roman numerals or Arabic numerals just make sense to people from other cultures, they had to learn each others notation just like any other language and eventually settled on Arabic numerals. Maybe things would have gone differently if the Mayans had a say.

It has been my experience that people who have not had the experience rarely get it

A pattern I've seen in my experience is that some person or group will put forth a pretty good idea, and others become dogmatic about that idea, loose sight of pragmatism, and try to push the idea beyond its practical applicability. I'm not saying this is you. I haven't yet read the Ken Iverson paper (I will). My suspicion at this point and after seeing the APL code demos is that there's probably plenty of good ideas in there, but APL doesn't strike me as pragmatic in any sense.

On Wed, Nov 6, 2019 at 11:06 AM Martin Euredjian via Python-ideas <python-ideas@python.org> wrote:

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.

I encourage everyone to read this Turing Award presentation:

"Notation as a Tool of Thought" by Ken Iverson, creator of APL

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

-Martin

On Tuesday, November 5, 2019, 11:54:45 PM PST, Richard Musil <risa2000x@gmail.com> wrote:

On Wed, Nov 6, 2019 at 5:32 AM martin_05--- via Python-ideas <python-ideas@python.org> wrote:
In other words, these two things would have been equivalent in Python:

a ← 23

a = 23

I do not consider these two things conceptually equivalent. In Python the identifier ('a' in this case) is just label to the value, I can imagine "let 'a' point to the value of 23 now" and write it this way: "a --> 23", but "a <-- 23" does give an impression that 23 points to, or is somehow fed into, 'a'. This may give false expectations to those who are coming to Python from another language and might expect the "l-value" behavior in Python.

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?

Richard
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