Understanding ASCII: Standards, Python and Rust Implementations

ASCII (American Standard Code for Information Interchange) is a 7‑bit character encoding standard defined in RFC20 (1969) that maps characters to binary codes for data exchange.

The article explains the structure of the RFC20 specification, including code ranges, character representations, and examples such as the binary representation of 'a' (01100001) and 'K'.

It then shows how common programming languages provide built‑in functions for ASCII conversion, using Python's ord() and chr() as simple examples that convert between characters and their decimal codes.

Because Rust does not include ASCII conversion in its standard library, the author presents a custom Rust crate asciis that implements ord and chr methods using a HashMap . The implementation details, including the init() method that builds the map and the ord function that returns Option<i32> , are shown.

Documentation tests for the crate demonstrate correct behavior, and the article provides the test output confirming that both methods work as expected.

Finally, the article summarizes the key points about ASCII, its relevance, and encourages readers to explore the source code on GitHub.