The Seasoned Scratcher

Sunday, August 16, 2015 · 12 min read

Your hosts for the evening are Hardmath123 and technoboy10 from Scratch. Together, we have over 13 years of experience with Scratch and the computer science world beyond.

So you think you’re a Scratch expert. You know the ins and outs of Scratch like the back of your hand. You may even have hacked around with the Scratch source code.

But you want something new. You want to learn more, explore, and discover. And you don’t know where to start. Everyone you ask gives you their own advice.

Here’s ours.

Which language should I learn?

The eternal question. A lot of people define themselves by the programming languages they use. People have very strong, emotional opinions about these things. The truth is, in the big picture, you can get most things done with most languages.

So before you pick a language, here’s a piece of advice: don’t collect languages, collect paradigms (that’s CS for “big ideas”). Once you know the big ideas, learning a new language should take you at most a weekend. Paradigms stay the same; they just show up in different languages hidden in a new syntax.

Having said that, here are the big ideas we think you should look at.

Functional programming is programming with functions. That means, in a way, that you’re more focused on reporter blocks than stack blocks. You don’t assign to variables much; instead of changing data in-place, you create copies that have been modified.

A lot of people think functional programming is impractical when they first get started–they don’t think you can get useful things done, or they think functional languages are too slow. Paul Graham, founder of Y Combinator (a Silicon Valley start-up which has more money than you want to know about) wrote this piece on how his company very successfully used a functional language called Scheme to “beat the averages”.

Scheme is one of the oldest languages around. It started off as an academic language used in MIT’s AI labs but over decades has evolved into a more mainstream language.

Many people have written their own versions of Scheme. The most popular one, and the one we recommend, is Racket, which was built by an academic research group but used by everyone–even publishers of books. It comes with a lot of built-in features.

The best book to learn Scheme (and the rest of computer science) is The Structure and Interpretation of Computer Programs, aka SICP. It’s free to read online. Another good one is The Little Schemer and its sequel The Seasoned Schemer.

If you want to learn functional programming but still want Scratch-ey things like blocks and sprites, learn to use Snap!. Snap! is Scratch with the advanced Scheme features thrown in.

(Bonus: Here’s Brian Harvey, the creator of Snap!, on why Scheme should be taught.)

If you want to know more about Snap!, ask us on the forum thread.

Object-Oriented Programming is based on the idea of grouping data and functions under structures called “objects”. A lot of languages provide object-oriented features, and so you’re likely to run into the ideas no matter what you choose to do.

The classic object-oriented language is Smalltalk—if you recall playing with the Scratch 1.4 source code, you were writing in Smalltalk. Smalltalk is an old language and isn’t used by anyone anymore. However, its legacy lives on: much of its syntax and some of its ideas are evident in Objective-C, the language in which you write iOS and OSX apps.

Another OOP language, Self, preached prototyping: a special kind of object-oriented programming where objects come out of “factories” called prototypes. You literally make a copy of the prototype when you make a new object. Self let you treat prototypes as objects themselves. It was very meta. This tradition lives on in JavaScript’s object-oriented style. JavaScript is the programming language of the web: originally designed for making webpages interactive, but now used for desktop software as well using Node.js.

The other kind of object-oriented programming is based on classes, which are pre-defined kinds of objects. Your program is a list of definitions for classes, and right at the end you create some instances of the classes to get things done. This pattern is the focus of the AP Computer Science course, which teaches you Java (more on this later). Java was widely used in industry for many years, and is still popular (though less so than before).

Statically Typed Languages are languages which care a lot about what kind of thing your variables are. In Scratch, you can put a string into the addition reported block and not have horrible things happen to you. Scratch isn’t statically typed.

In a statically typed language, you will be warned that you can’t add a string and a number even before you try to run the program. It will refuse to let you run it. For huge codebases managed by hundreds of programmers in a big company, this helps prevent silly errors. Though static typing probably won’t help you much on a day-to-day basis, the ideas are worth learning about and you should eventually get familiar and comfortable with the paradigm.

Java, as mentioned before, is statically typed. Other such languages are Mozilla’s Rust and Google’s Go-lang. A recent trend is to add static typing onto JavaScript, because plain old JavaScript is not very type-safe. You may have heard of TypeScript by Google or Flow by Facebook.

The C programming language is also statically typed. C is extremely low-level. It gives you a lot of control over things like memory use, the operating system, hardware, networking, and processes. This lets you write very efficient programs, but also makes it difficult to learn. It’s useful to have a working knowledge of what the C compiler does, and how assembly languages work. As such, learning C won’t teach you as much of the mathematical side of computer science as the practical side.

Finally, Haskell is an old academic language that is making a serious comeback. Haskell is statically typed with a very advanced type system. It is also functional. It has a lot of neat language features, but is not very beginner-friendly for a variety of reasons.

Logic programming or declarative programming is a completely different outlook on programming. Rather than telling the computer how to do something, you tell it what to compute and the computer tries all possible inputs until something works—in a clever and efficient way, of course. You can use it to solve a Sudoku by explaining the rules of the puzzle without giving any hints on how to solve it.

It looks like the computer is reasoning on its own, and in fact logic programming is closely related to automatic proof generation.

Logic programming is mainly an academic thing with not too many practical applications in the Real World™. One application is database querying with languages like SQL, which try to find all elements in a data base which satisfy some criteria.

The popular languages of this paradigm are Prolog and Mercury.

We mention logic programming here only to give you some idea of what other paradigms are out there. If you learn functional programming with SICP (above), you’ll learn the basic ideas. As such, don’t worry too much about learning logic programming unless you’re really interested in this stuff. You won’t find yourself writing any “practical” code in Prolog.

Other well-known books on this material are The Reasoned Schemer and The Art of Prolog.


Having said all that, here’s a recap of the languages you might care about, what they’re good for doing, what paradigms they try to embrace, and what we want to say about them.

Here are some languages you shouldn’t care about:

Still confused? Here’s a flowchart to help you out (click for a large SVG, or try Tim’s interactive Scratch project):

Flowchart

Finally: your personal experience and preference is far more important than anything we say. We cannot recommend a practical language any better than one you are already productive in (pedagogical languages, however, are a different deal).

So we’ve come a full circle: collect paradigms, not languages.

Tools of the trade

Programmers in the Real World™ are very dependent on their tools. In fact, though we don’t recommend it, most people define themselves by their tools.

This is largely because many of the more established tools in the CS world have a very steep learning curve (because they were written by lazy hackers who want to minimize keystrokes).

Here are our recommendations for what to invest in.

A text editor: Text editors are sacred, because in theory they’re the tool we spend the most time using. We can’t really recommend one because whatever we say, we’ll face lots of heat from supporters of some other one. Instead, here’s a short list of editors you might consider. All of these are free and available for Mac/Linux/Windows.

The command line: learn to use bash from your terminal. It is extremely empowering. The command line is the key to the insides of your computer, and turns out to be surprisingly easy to get started with. Start with simple operations like creating (touch) and moving (mv) files. Use less to read them, and use pico or nano (or vim!) to edit them. Along the way, learn important components of the UNIX philosophy by piping programs to each other. Learn how to use regular expressions with grep; this is life-changing because regular expressions show up in every language and give you a lot of power over strings. Figure out how to use man pages and apropos to get help. Soon you won’t be able to live without the command line.

Git: For better or for worse, the most popular way for you to share code these days is using a website called Github. Github is a web interface for a tool called git, which is a version control software (another one is hg, a.k.a. Mercurial). git lets you keep track of your code as it changes, and lets other people contribute to it without having to email different versions of code around. It’s not that hard to learn, and you’ll need to learn it if you want to contribute to any projects these days.

Tip from hardmath123: Don’t worry if you don’t truly grok git. It’s my personal hypothesis that nobody really understands it. Just have enough working knowledge to get stuff done.

IRC: IRC or Internet Relay Chat is a decentralized chat protocol, which means it’s like Skype except not controlled by any one company. It’s been around for a while–it was used to organize a 1991 Soviet coup attempt. You want to learn to use IRC because it’s not very intuitive at first look. But many communities in the tech world communicate through IRC chatrooms, called “channels”; it’s a great way to reach out and get help if you need it. The best way to get into IRC is to just dig in–use Freenode’s webchat client at first, then experiment with others (Weechat, IRSSI, IRCCloud, etc). Feel free to say hi to us: we’re hardmath123 and tb10 on Freenode.

Find (good) documentation: know about StackOverflow, Github, MDN, etc. We won’t drone on about these sites. Just know that they exist.

Tip from technoboy10: Google is a coder’s best friend. Everybody has a different way of finding solutions to programming problems, but learning to search and find answers online is an immensely valuable skill. If you’re not a fan of Google, I recommend the DuckDuckGo search engine.

Folklore and Culture: some reading material

The CS world, like any community, has its own set of traditions. It’s said that UNIX is more an oral history than an operating system. With that in mind, here are some books, articles, and websites for you to peruse at your leisure.

Don’t take any of them seriously.

(Disclaimer—some of these may have PG-13-rated content.)

Parting words

You’re about to start on a wonderful journey. Enjoy it. Make friends. Make mistakes. These choices are all meaningless; you’re smart and you’re going to be alright no matter what text editor you use or which language you learn.

Hack on!

◊ ◊ ◊
(Click to load comments…)