Rust: Pattern Matching and the Option Type

Abstraction: Rust Option type eliminates null pointer bugs via exhaustive pattern matching

Key points:

• Rust has no null pointers; absence of value is represented by Option<T>, an enum of Some(T) or None.
• Pattern matching on Option is exhaustive — the compiler rejects code that does not handle the None case, preventing segfaults that C/C++ allow.
• C.A.R. Hoare called the null pointer his "billion-dollar mistake" (invented 1965 in ALGOL W).
• Rust's if {} else {} blocks are expressions, not statements; the last expression without a semicolon is the return value.
• IEEE 754 floats encode special values (±Infinity, NaN) for similar reasons — representing the absence of a meaningful numeric result.

Connections: Rust · Option Type · Pattern Matching · Null Safety · Type Systems

Source: http://nickdesaulniers.github.io/blog/2013/05/07/rust-pattern-matching-and-the-option-type/