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Comment by dkarl | Hacker News Reader

Physicists, mathematicians, and engineers have been writing µ and u on chalkboards for years with no issues. Why should it be harder on a screen?

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The difference is that form is important in mathematics and not very important in programming. Therefore symbols are used because it makes it easier for the eye to recognize patterns.

For example these equations look similar,

x^2+4x+5=0

y"+4y'+5=0

Even though one is a polynomial equation and the other is a differential equation, the common visual pattern suggests that the techniques needed to solve them may be similar.

On the other hand in programming there's no need to do this, all the math has already been worked out on paper, so it's better to use clear, distinct, easy to type variable names.

> form is important in mathematics and not very important in programming

How important is form when I'm programming mathematics?

> How important is form when I'm programming mathematics?

Not important.

As a physicist who does a lot of mathematical programming for my every day job, I'm going to disagree pretty hard.

With how I've defined form, I'm not sure how you could.

Who in their right mind does math on a computer, math is implemented on a computer, but it's done by hand.

> Who in their right mind does math on a computer, math is implemented on a computer, but it's done by hand.

Maybe you think this becuase your used to writing math on computers that make writing that math ugly and obtuse?

Besides, having the math you've written by hand closely match the syntax you use on the computer can greatly reduce the cognitive burden of switching between code and paper.

I'll just make one brief comment in regard to wanting the math you've written by hand to closely match the syntax on the computer, and say that this is rarely the correct thing to do when writing high quality numerical software.

Making your code performant, and doing a thorough numerical analysis, usually requires a significant rearrangement of your formulae.

I'm sure there is so much room for improvement here. The closest thing for me is using TeXmacs: https://m.youtube.com/watch?v=H46ON2FB30U

Usually, the formulas I derive on paper end up quite complicated and can not be simplified away. When I am numerically implementing the formula, I want that it matches closely what I wrote in the paper, and long variable names would make my code less clear mathematically.

Why would I use the variable name "probability_distribution_on_m" instead of "rho_m", when I know all along what rho_m means in the contexte of my code (the symbol use throughout the paper). Usually, I comment at the beginning and specify what the variables mean and to what they correspond in the paper. And if somebody needs to read my code, that person will need to understand the paper first. More descriptive variable names won't make the person understand the paper better.

Of course, when I am writing some non-scientific software, I will use descriptive variable names, because there is no complicated formula, no paper that sets the context of the code, and it makes sense in general to have descriptive variables for logic elements for a clear code.

I didn't say to make your variable names verbose. rho_m is fine in my opinion, although I find it strange that you would name a probability distribution rho unless it's a density matrix. I would probably name it prob_dist_m, or even pdist_m if you want to be more terse.

What I do think is bad form would be naming it ρ_m.

How exactly do you type mu? On a chalkboard writing the mu sign is trivial, on a computer... well I don't have a mu button.

Edit:

There are like 5 replies to this mentioning different ways of doing it (including memorizing 3 digit unicode values) none of which seem more intuitive than writing "mu".

For me: alt+enter (switches to Greek keyboard layout), m, alt+enter (back to usual layout). I use Greek symbols in Python and in Javascript. I do it almost without thinking now, as lots of my coding is tightly linked to maths.

you can map a useless key like capslock to do that in a single step. Thus to type μ, for example, you simply press CAPS+m, and similarly for all greek letters

What is a capslock key, I only have ctrl and hyper ;)

man, it's the only key that has an assigned light in my keyboard! Funnily, the capslock light in my laptop seems to be detached to the configuration of that key, so that the light shows the parity of the total number of greek characters that I have typed.

You probably have what is called a GUI key, hyper died out with the space cadet keyboard. Caps lock is above the left shift.

I type <Greek>-m. One extra keypress, just like when I type é, ü, č, ç, π, etc. If you type in more than one language, or math, your keyboard is already set up to handle this.

in Julia:

\mu<tab>

Vim/Neovim makes it very easy to input all kinds of interesting Unicode, using the "digraph" system. A lot of other code editors have similar functionality, either through keystrokes or some kind of "palette" interface. And Julia REPL itself has Tex-like escape sequences.

I agree that we need better system-wide tools for arbitrary Unicode input. Font support and confusable glyphs are also issues. But I think these are solvable problems, and they will be good problems to have solved.

On Windows you can use Autohotkey and map it to "Right Windows Key" + u. Or use "Right Alt Key"+ "Numpad 230" ALT Code, https://usefulshortcuts.com/alt-codes/greek-alt-codes.php)

I use on Linux the XCompose key (which is assigned the menu key right from the space bar, or the "Print Screen" key), and then "\mu" like in LaTeX. I don't need to think about it because I have used LaTeX for years. I also use the XCompose to generate € and ß which are special symbols in my native language. This has the advantage that I can use the UK International layout for everything, which makes specifically writing code much more comfortable. Also, the xcompose keymap is just a text file in my home directory, I can extend it at any time and take it with me. The method is also independent from any application.

Also, Emacs has an input method which supports "\mu", and this convention is also used in Racket for things like λ.

> none of which seem more intuitive than writing "mu"

Write for the convenience of the reader, not of the writer!

I just do \mu (or ;mu) in Emacs.

We're in the 21st century, all the tools we use should have reasonable Unicode support. The fact that we collectively keep on talking about typing non-ASCII characters as a real problem is a pretty depressing reflection of our shared computer infrastructure :(.

In the Julia REPL and most Julia editor extensions you can just use \mu <tab> and call it a day. This is a non-issue for Julia users.

It's not the screen so much as the keyboard that is the problem

They’re very easy to type in Julia’s repl, or any text editor with Julia support.

You just type \mu and then hit the tab button and you get μ. I actually switch over to my Julia REPL all the time when I’m emailing someone and want to type a greek character.

> with Julia support.

So you can see how this becomes a bit of a barrier to entry.

I'm not sure I'd want to do any serious coding in an editor that doesn't have the most basic support for the language I'm using, but to each their own I guess.

For new users, if they're not used to writing unicode characters and don't have an editor with nice support, then they don't have to write them.

The julia community has a pretty strong convention of giving both unicode and ascii versions of almost all functions. Some packages don't have this convention, but I'm not aware of any big important ones that don't follow it.

Anyone that doesn't use a language aware editor is making themselves a disservice.

that's not really acceptable. I'm a big julia fanboy, have been since 0.4 (proof in bio) but dismissing real pain felt by newcomers is kind of bad for the ecosystem.

What editor do you use, if I may ask, and have you asked them to add unicode support? Part of the goal in permitting unicode variable names is that more and more niche editors might be forced to become fluent in languages other than english, benefits everyone (and might be a bit overdue at this point).

I use vim, and have a completions plugin (part of julia-vim mode), so that I can write \mu<tab> for any unicode name, which makes it as easy to type as "mu", but easier for me to read (as it matches my textbook expectation of the formula).

It's not a display issue. Do I want to type ctrl-u <whatever hex> or copy-paste if I want to write some code that calls a function when I'm playing around with a new library? Well those are the two strategies I've used with experience... But some person coming new to Julia will grab some package, and then see some function call and get deer in the headlights "how the hell do i do this".

And LaTeX codes are not always obvious. For example it's \triangleleft but \leftarrow

that's two extra strokes than just "mu"

Code is read more often than it's written, even scientific computing code.

agree, that doesn't make it not a problem.

It is a non-issue when you can use just use autocompletion for mathematical symbols on almost all Julia-supported editors

If Emacs doesn't have enough input methods, you can add one reasonably easily... A good deal of early-ish work on multilingual support in Emacs was done out of interest in editing technical text, which is basically the same problem as more-or-less complex natural language scripts (which deserve support anyway, of course).

Besides the good points about the difficulty typing characters, not all fonts have good glyphs for non-alphanumeric (by that I mean low ASCII) characters. Sometimes they don't have those glyphs at all and the system has to go to a fallback font. Terminals can also shit the bed with Unicode characters.

The solutions to those problems is to use better fonts, terminals, and editors. Using Unicode characters is fine but some people do have legitimate problems with them.

> Besides the good points about the difficulty typing characters, not all fonts have good glyphs for non-alphanumeric (by that I mean low ASCII) characters

Not all fonts are good fonts for an evey use use; heck, not all fonts make 0 and O or 1 and l and I clearly distinguishable.

> The solutions to those problems is to use better fonts, terminals, and editors

Exactly.

On that topic, I'll throw in a shoutout to Cormullion's excellent JuliaMono font [1,2]!

Typing certainly does add more friction between u and µ than a chalkboard would, though it is perhaps also notable that mathematicians seem to have felt that it's worth the effort, and have come up with a quite nice system for it in LaTeX -- and I would certainly not mind seeing more languages and editors add support for LaTeX completions the way the Julia ecosystem has.

[1] https://juliamono.netlify.app/

[2] https://github.com/cormullion/juliamono

Because of keyboards?

Because they dont do it at all on a screen. All papers written in Latex use \mu .

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