Kids Coding: Simple Java
murrayc.com
murrayc.com
https://leanpub.com/programmingforkids
It's currently Mac-only, because of the `say` command, and so that I could write instructions for just one platform. I have ideas about how I'm going to fix that, but that won't be in the near future.
My son was about the same age when I started writing it, but the book scales nicely for any 9-14 year old, I think. Please feel free to give your son a copy, and let me know if it's helpful.
There's a package on Debian Linux based systems called "gnustep-gui-runtime" which (among a lot of other things) provides the "say" command.
The self initiated work I've seen kids create out of Scratch is seriously impressive and creative.
The blog author and a commenter make a good point about how back in the day getting the computer to do just about anything was thrilling, whereas now expectations are a lot higher but so is the knowledge and effort required to make that happen.
Switching on a computer and getting nothing but a ready prompt somehow made it easier (or more necessary?) to make your own fun.
I picked up Human Resource Machine when it came to the Nintendo Switch a few months ago, and I loved it pretty immediately. I think it does a great job of abstracting out the fact that you're writing assembly, masked by their very dark sense of humor (Little Inferno, anyone?). Whenever one of my friends (other grown-ups, not even kids) say things similar to wishing they knew how to program, I suggest they pick the game up and give it a try. It's like jumping in the deep end, but does a good job of showing how to think like a computer would think.
Another son is going through Swift Playgrounds and finding that easier to understand. He couldn't get HRM at all but immediately understood what simple functions were for in Playgrounds.
The hello world example is symptomatic:
public class Example {
public static void main(String ...args) {
System.out.println("Hell, World!");
}
}
fun main(args: Array<String>) {
println("Hello, World!")
}
// java
for (Element element : collection)
// kotlin
for (element in collection)
// java
(OtherType) somehting;
// kotlin
somehting as OtherType
// java
a.equals(b);
// kotlin
a == b
// java
Color color = x < 5 ? Color.RED : Color.GREEN;
// kotlin
val color = if (x < 5) Color.RED else Color.GREEN
Just the way it allows you to create an inmutable class in a single line already makes it way easier to read, while also saving time.
Compare Java:
public class Person {
private final String name;
private final int age;
public Person(String name, int age) {
this.name = name;
this.age = age;
}
public String getName() {
return name;
}
public int getAge() {
return age;
}
}
data class Person(val name: String, val age: Int)I TAed an intro to CS class in Python for a number of years. I am rather ambivalent toward Python as a developer, but as a first language to be taught it worked pretty well. There are others, but having the minimum amount of noise for some basic coding examples I think is incredibly helpful (though I admit, I think I'm basically just saying "I think dynamically/optionally typed scripting languages > statically, explicitly typed compiled languages for this task").
program HelloWorld;
begin
end.
import typingYou may also be overestimating how much easier Python is to learn for a complete beginner. When I was 12 or so I discovered Python via RenPy (https://renpy.org) and although I could type some simple commands into the REPL, even the fact that you could put your code into a file to execute later was non-obvious to me. My experience with Processing was much smoother in comparison.
In my opinion, you should focus less on syntax and more on getting to an engaging experience with a fast feedback loop.
OOP in Python is something I really cannot like. I teach the language to children and as soon as I get to objects (which is not avoidable in Python, as many libraries and the language itself use objects) the number of concepts I have to explain is too much and I get the dreaded blank stare. I haven't so far found a short explanation that gives them a good enough grasp on objects that they can start making their own.
Ideally I would like to have to explain few orthogonal concepts, as learning a new concept in the abstract is hard and their mind has little patience for it, and let them experiment as soon as possible. But experimentation needs the minimum mastery required to combine the concepts and get some result. Pyhton's objects tend to expose their functions+struct guts, which does not help.
And don't get me started on warts like the "global" keyword, which makes simple scripts with global state and a few functions (a step into learning functions and structured programming) a frustrating and buggy process. I still cannot understand async/await enough to be comfortable with it, and if Armin Ronacher doesn't either... Meanwhile, languages like Oz do concurrency, with actual parallelism, beautifully.
I'm starting to think Scheme and Smalltalk would be excellent beginner languages. "Here's how to make an s-expr; these s-expr are applications, these are definitions. Now go."
I would not expect to get to objects _properly_ (maybe things like list()) in an introduction to programming course, I think you can get very far with just functions and simple data types.
Then, once you do want to introduce objects, I think Python's class system can be kept simple enough to begin with, and the parts that are inherently tricky (like self) have equivalently tricky parts in most other languages anyway.
I think a course teaching programming that goes into async IO, needs to discuss 'global' (something I've still used only twice in 5 years of Python), talks about decorators, etc, is doing something seriously wrong.
I don't know a lot about Smalltalk, but Scheme is an interesting idea for a first language. I think it could be a good first language, but I would be concerned about what the next step is. Having learnt Python, there are lots of next steps because it has a large and active ecosystem with plenty of opportunities, I'm not sure Scheme has the same, and I feel learning a second language, while Scheme might be good preparation, is not going to be straightforward for someone who has only just learnt to code.
When I was there, at least, the focus was on basic programming concepts, functions, variables, loops, recursion, conditionals, and library interaction was largely imperative, more focused on successful execution than on the organization of the code.
> While there are many oddities, I think Python lets you ignore them
Yes, thankfully. But libraries that will make programming interesting for children usually have a rather sophisticated design, including an object-oriented interface. Pygame is slightly too complex for my taste and installing it on Windows is a pain (not Python's fault). I've tried Pyglet on that platform, despite its hard API, and am I right now comparing two students, one on each framework (although the Pygame one uses pgrun).
Once they've used Python as a means to get a game displayed, it seems easier to teach Python's useful minutiae as it helps them code. Not enough experience to assert this with certainty though.
> Then, once you do want to introduce objects, I think Python's class system can be kept simple enough to begin with, and the parts that are inherently tricky (like self) have equivalently tricky parts in most other languages anyway.
Python's OOP really has more complexity than needed. Smalltalk does objects simpler. Alan Kay used it to teach programming to children (the seventies version, the public '82 version had more stuff, meant for adults.) Children can learn to program _starting_ with OOP, not structured programming, but Python (or Java, or...) will not help you there. It seems to expect its user to understand OOP in terms of structured programming, which a practicing programmer certainly can, but a child with limited abstract thought?
Interestingly, Alan Kay was a lisper, which brings me to...
> I don't know a lot about Smalltalk, but Scheme is an interesting idea for a first language.
Can't be sure without trying it, but probably. The scheme community has projects in teaching CS through game programming, with at least one scheme dialect for games and accompanying IDE where images are first-class objects, displayed in the code.
> I think a course teaching programming that goes into async IO, needs to discuss 'global' (something I've still used only twice in 5 years of Python), talks about decorators, etc, is doing something seriously wrong.
I can see how it came out that way, but I don't teach async IO to children; I try to teach some Python to colleagues from time to time.
As for 'global', was your programming activity the one of a beginner? When you have someone that successfully wrote a single script with variables and control structures, you will want them to start writing functions to complete the introduction to structured programming. You will want to make them reuse the existing state, and once they discover the limitations of it, slowly introduce local variables, scoping rules and so on. My students often have the right reasoning at this stage but forget 'global', _repeatedly_ (that's the important part -- hint of a bad UI), which means I have to explain scoping rules, which seem to them like unnecessary wanking at this point.
Guido's attention to newbie-friendliness is obvious, but Python is old and has accumulated cruft, and its developers have blind spots. Zed Shaw listed some of them. Also don't forget that a professional in IT has developed a thick skin when it comes to complexity, or less charitably, learned helplessness in the face of shitty design. Where we think a system's idiosyncrasies are mere details (or worse, the right way to do things), an innocent mind will refuse to engage.
I don't think Python is a great language longer term, but its simple syntax and lack of ceremony makes it pretty much ideal for beginners.
Why is it far more important that people get an understanding of simple procedural logic first? (And what is it exactly? I've had a 'procedural' feeling when seeing: - assembly code - structured programming (Algol 60 and descendants) - even some kinds of logic programming)
processingRun() {
$HOME/processing/processing-java --sketch=$1 --run
}
alias processing-run=processingRun
processing-run()
{
~/processing/processing-java --sketch="$1" --run
}