Matthew Cheok

This is a follow up to Writing a Parser in Swift (I), I'd highly suggest reading that first if you haven't already.
Last time, we looked at Context-free Grammars, Recursive Descent Parsing and Operator Precedence Parsing. Let's complete the missing pieces in our trivial language, Kaleidoscope....

This is part two to Writing a lexer in Swift. If you haven't caught that, you might get more context following that first.
In this post, we'll look at how to build an Abstract Syntax Tree from a series of tokens.
Firstly, we'll look at how to construct a grammar that describes what is allowed in the language. One of the useful tools we have is the Context-free Grammar. This allows us to describe the language as a set of rules called productions. In fact, the...

NSNotificationCenter has been around for a long time. It let's you post arbitrary notifications and decouples the source of the action from the destination. There are a few flaws though:
The notification name is a String type which is subject to typing errors or enforces a design pattern where you would declare constants to avoid this....

In this series, we'll attempt to write parts of a compiler for a simplified language, Kaleidoscope. If you're interested in following along in C++ or Objective Caml, you can find the original tutorial here on the LLVM website.
The goal here is not to write the most efficient implementation but how we can leverage features in Swift to make ourselves easily understood....