Standard ML Facts for Kids

Standard ML is a special kind of programming language that helps computers understand instructions. It's part of a family of languages called ML. Think of it as a tool that helps people build other computer tools, like programs that translate code or programs that check if mathematical ideas are true.

Standard ML: A Smart Way to Code
Example
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Standard ML: A Smart Way to Code

Standard ML, often called SML, is a programming language that uses a style called functional programming. This means it focuses on what a program is rather than how it does things. It's like giving a computer a recipe where each step is a function, and these functions don't change anything outside of themselves. This makes programs easier to understand and less likely to have mistakes.

What is a Programming Language?

A programming language is a set of instructions that a computer can understand. Just like humans use languages like English or Spanish to talk to each other, programmers use languages like Standard ML to talk to computers. These languages allow us to create software, apps, and websites.

What Makes Standard ML Special?

Standard ML is known for its clear and logical way of handling information. It uses a concept called type inference, which means the computer can often figure out what kind of data you're working with without you having to tell it every time. This saves time and helps prevent errors. It also has a strong type system, which means it checks your code carefully to make sure everything fits together correctly before the program even runs. This is like having a super-smart assistant who catches your mistakes early!

Understanding Functional Programming

In functional programming, you build your programs using "functions." A function is like a mini-program that takes some input and gives you an output, without changing anything else in the computer's memory. Imagine a calculator: you give it numbers (input), and it gives you an answer (output). It doesn't mess with other parts of your computer. This makes programs very predictable and easy to test.

What Can Standard ML Do?

Standard ML is often used in areas where accuracy and reliability are super important. It's not usually used for making video games or social media apps, but it's great for more technical tasks.

Building Compilers

One common use for Standard ML is creating compilers. A compiler is a special program that translates code written in one programming language (like Standard ML) into another language that the computer can directly understand. It's like a translator that turns human-readable instructions into machine code. Many compilers for other programming languages have been built using Standard ML.

Proving Things with Computers

Standard ML is also used in something called theorem provers. These are computer programs that can check if mathematical statements or logical arguments are true. Imagine a super-smart detective that can go through complex logic and tell you if it holds up. This is very important in fields like computer science and mathematics to ensure that systems are correct and safe.

Example

Here is a simple example of a function written in a style similar to Standard ML. This function calculates the factorial of a number. The factorial of a number (like 5!) is 5 × 4 × 3 × 2 × 1.

fun fac (0 : int) = 1    (*  the : int part means that 0 and n are integers *)
 |  fac (n : int) = n * fac (n - 1)

This code says:

If you want the factorial of 0, the answer is 1.
If you want the factorial of any other number 'n', the answer is 'n' multiplied by the factorial of 'n minus 1'. This is a clever way to make the function call itself until it reaches 0.

Standard ML facts for kids

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