computer science

Smalltalk

Smalltalk is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Smalltalk rather than just read about it. In short: Smalltalk is a purely object-oriented programming language that was originally created in the 1970s for educational use, specifically for constructionist learning, but later found use in business. It was created at Xerox PARC by Learning Research Group (LRG) scientists, including Alan Kay, Dan Ingalls, Adele Goldberg, Ted Kaehler, Diana Merry, and Scott Wallace.

Key takeaways

Smalltalk belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Smalltalk to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Smalltalk from memory before moving on to harder problems.

Reference excerpt

Smalltalk is a purely object-oriented programming language that was originally created in the 1970s for educational use, specifically for constructionist learning, but later found use in business. It was created at Xerox PARC by Learning Research Group (LRG) scientists, including Alan Kay, Dan Ingalls, Adele Goldberg, Ted Kaehler, Diana Merry, and Scott Wallace. In Smalltalk, executing programs are built of opaque, atomic objects, which are instances of template code stored in classes. These objects intercommunicate by passing of messages, via an intermediary virtual machine environment (VM). A relatively small number of objects, called primitives, are not amenable to live redefinition, sometimes being defined independently of the Smalltalk programming environment. Having undergone significant industry development toward other uses, including business and database functions, Smalltalk is still in use today. When first publicly released, Smalltalk-80 presented numerous foundational ideas for the nascent field of object-oriented programming. Since inception, the language provided interactive programming via an integrated development environment. This requires reflection and late binding in the language execution of code. Later development has led to at least one instance of Smalltalk execution environment which lacks such an integrated graphical user interface or front-end. Smalltalk-like languages are in active development and have gathered communities of users around them. American National Standards Institute (ANSI) Smalltalk was ratified in 1998 and represents the standard version of Smalltalk. Smalltalk took second place for "most loved programming language" in the Stack Overflow Developer Survey in 2017, but it was not among the 26 most loved programming languages of the 2018 survey.

… excerpt ends here. Continue reading the full article.

Illustrations

Smalltalk: Smalltalk-80: The Language and its Implementation, also known as the "Blue book", an original book on the language — Smalltalk-80: The Language and its Implementation, also known as the "Blue book", an original book on the language

Worked examples

Example 1 — a first encounter with Smalltalk

Start with the simplest possible case. Write down what Smalltalk claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Smalltalk before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Smalltalk ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Smalltalk

In research: Smalltalk appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Smalltalk in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Smalltalk is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1972 software, Class-based programming languages, Cross-platform free software, so understanding it makes those chapters shorter.
In everyday life: Look for Smalltalk outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Smalltalk in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Smalltalk means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Smalltalk out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Smalltalk in simple terms?

Why does Smalltalk matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Smalltalk?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Smalltalk.