Actually, the code reads a simple language, uses recursive descent parsing to build a tree, and then uses a “compiler” to convert the tree to JavaScript (which can then be executed, of course).

The idea is related to recursive descent parsing, where you attempt to parse certain things, and if those things fail, you try again. There are ways to match in a fuzzy way using Levenshtein distance.

It can be accessed from ruby-lang.org. Featured is the Prism parser as a default gem. Prism is billed as a portable, error-tolerant, maintainable, recursive-descent parser for the Ruby language.

Topics include grammars, syntax, elements of parsing and recursive descent, semantics, basic code generation, fast compilation runtime support. Programming project required.

Patterns in JavaA tale of three patternsby Kevlin HenneyListing 1. Iteration over a sorted binary tree using recursive descent in an enumeration method.