If you've ever used Lark, you probably already know that it's rather featureful compared to other parsing libraries. Even when it was first released, five years ago, it already had two parsing algorithms, several lexers, automatic AST construction, automatic line counting, and the list goes... View Article
The first time I used Logo, it felt like magic. I could type a short sequence of simple commands, and draw beautifully complex shapes on the screen. In this tutorial, I will show you how to parse and interpret a Logo-like language in just 70... View Article
Three months ago, I wrote a post detailing the process of writing a calculator using a parsing library. The popular response, however, was that readers are far more curious about seeing a calculator written from scratch, with the batteries included but nothing else. I figured, why... View Article
Python classes are great. But they can be better. Take a look at this class, let's call it Foo: Yes, try as it might, this puny class doesn't even know if it's bigger than 0 or not! It would not help to define a __gt__... View Article
Over the years, I noticed that many developers are reluctant to use parsing libraries, especially if the language they need to parse is relatively small. The reason is that they wish to avoid adding external dependencies to their project. Although pip (setuptools) can automatically fetch... View Article
Introduction In this post I will demonstrate how to parse and calculate an arithmetic expression a general-purpose parser. When we're done, we'll be able to handle expressions such as 1 + 2 * -(-3+2)/5.6 + 3, and hopefully you'll have gained the tools to handle... View Article
I am a big fan of assertions. Whenever I reach a point in my code where I say "that pointer can't possibly be null", I immediately write - assert( p != NULL ); - and whenever I say "this list can't possibly be longer than 256"... View Article
It's been a long time since my last post, and it would be appropriate that I post about whatever it is that I've been working on. But I won't. I'm writing this post only to tell you about an interesting new python library I stumbled... View Article
Copy-on-write (COW) is a popular mechanism of lazy evaluation, that helps improve running speed and reduce memory requirements by transparently delaying the copying of data. Essentially, this is how it works: When you try to copy an object, you are instead given a fake object.... View Article
For a long time now, I've been hindered by the issue of utilities, or snippets. These are convenience functions and classes that are too small or too incomplete to justify a library, yet are useful enough to be used. I've posted a few on my... View Article