Building A New Programming Language In Ruby: The Interpreter

In this blog post, we're going to start implementing the interpreter for Stoffle, a toy programming language built entirely in Ruby. You can read more about this project in the first part of this series.The interpreter we are going to build is commonly referred to as a tree-walk interpreter. In the previous post of this series, we built a parser to transform a flat sequence of tokens into a tree data structure (an abstract syntax tree, or AST for short). As you might be imagining, our interpreter has the job of going through the AST created by our parser and breathing life into a Stoffle program. I find this last step the most exciting one of this language implementation journey. When building the interpreter, everything finally clicks, and we are able to see Stoffle programs running for real!.