Mastering Rust - Second Edition

Type systems and why they matter

"Be conservative in what you send, be liberal in what you accept." - John Postel

Why do we need types in a language? That's a good question to ask as a motivation to understand type systems in programming languages. As programmers, we know that programs written for computers are represented in binary as combinations of 0s and 1s at the lowest level. In fact, the earliest computers had to be programmed manually in machine code. Eventually, programmers realized that this is very error-prone, tedious, and time-consuming. It's not practical for a human to manipulate and reason about these entities at the binary level. Later, during the 1950s, the programming community came up with machine code mnemonics, which ...