In the last chapter, the basics of the frontend component for a language were defined. This included defining tokens for different types of expressions, writing a lexer to tokenize a stream of input, chalking out a skeleton for the abstract syntax tree of various expressions, writing a parser, and generating code for the language. Also, how various optimizations can be hooked to the frontend was explained.

A language is more powerful and expressive when it has control flow and loops to decide the flow of a program. JIT support explores the possibility of compiling code on-the-fly. In this chapter, implementation of these more sophisticated programming paradigms will be discussed. This chapter deals with enhancements of a programming language that make it more meaningful and powerful to use. The recipes in this chapter demonstrate how to include those enhancements for a given language.