Going beyond Ruby: Writing a simple C extension

One big reason for using a C extension is to leverage existing libraries. Ruby's ecosystem sometimes has gems written on top of C libraries. For example, Nokogiri is a Ruby gem built upon existing C libraries (such as libxml2). By writing a C extension, we can directly interact with those C libraries from Ruby without reimplementing them. This means we can mix Ruby's productivity with battle-tested C code. Another reason is that Ruby is built on C. Learning how to write a C extension can help you understand Ruby's internal workings. For instance, we can look at the source code to understand how Ruby sorts an array under the hood.