Mako

For someone who already knows how to program, Python seems to be very easy to pick up. It's still a tremendously more complex language than BASIC. I help teach an after-school programming class for middle schoolers. Last year, we tried using Python. While some students got the hang of it, many seemed confused and demotivated. This year, I wrote a simple TinyBASIC REPL from scratch[1], aiming to produce the simplest subset of the language that made it possible to do interesting things and illustrate concepts like looping, branching, variables, etc. It was a big hit with the kids, and the whole class has been extremely engaged. As a next step, I've built a Logo[2] implementation so that we can move into writing modular, reusable procedures and play with graphics. Learning to program is almost entirely orthogonal to learning a language, and

I use my Forth system for writing video games: https://github.com/JohnEarnest/Mako It's also fun to implement features conventionally associated with high-level functional languages, such as lazy generators: https://github.com/JohnEarnest/Mako/blob/master/lib/Algorith...

Thanks! There's a few things about my dialect of Forth that are unusual if you've worked with Forth before, mainly just the fact that it is a "static" subroutine-threaded forth which lacks the ability to define new immediate words and it has some special-case syntax for string constants and the like. I do have a quick-start manual available: https://github.com/JohnEarnest/Mako/blob/master/docs/makoBas...

I've been using Forth for a while to write small video games, and honestly I find the process delightful. The extreme simplicity and flexibility of the language lend themselves well to the kind of special-case explosion that often occurs as I tinker with game logic, and puzzling out the cleanest way to express complicated ideas is very intellectially satisfying. Working on a simulated game console with no underlying operating system and unrestricted access to memory seems to be an ideal case for the language. If anybody's curious, all my development tools and forth code are on github: https://github.com/JohnEarnest/Mako

Honestly, maintaining the stack in your head is a skill that can be learned with practice. In my own experience, it was very hard at the beginning but over the course of a few weeks it became second nature. You get used to idiomatic ways of doing things- arranging expressions so that they don't become deep, factoring words apart as a means of reducing the number of elements you care about in a given context, when to use a variable or two to untangle a complex expression. From the debugging side, well-factored code consists primarily of short pure functions with a very small number of code paths. This couldn't be a more perfect scenario for TDD. In my own projects I use an extremely simple unit testing system called the Test Anything Protocol (TAP). Here's an example of a fixture: https://github.com/JohnEarnest/Mako/blob/master/lib/Test/te

Garbage collection isn't necessarily that difficult, especially when you're in a single-threaded (or cooperatively multithreaded) environment and don't have to contend with an OS. Here[1] is a cons-pair system I wrote in Forth which uses tag bits to identify pointers, a mark-and-sweep garbage collector and a free-list style allocator. GC takes linear time with respect to heap size, and allocations are constant time. The allocator itself (not counting all the list utility routines) is about 60 lines long and fairly easy to understand. [1] https://github.com/JohnEarnest/Mako/blob/master/lib/Algorith...

That's sort of the idea behind a project I've been tinkering with for a while called Mako[1]. It's an extremely simple VM that is essentially an idealized game console. I initially designed the system as a convenient way to play with compiler design (currently compilers for Forth, BASIC, FORTRAN and a BCPL-like language are available, in varying degrees of robustness), but having some limitations to work within has proven quite fun from a game development standpoint as well. A few of my friends and I intend to roll a linux distro for the RaspberryPi which makes it into a physical "Mako game console", and in addition to playing games[2][3][4](etc) you'll be able to play with an interactive Forth prompt.[5] [1]https://github.com/JohnEarnest/Mako [2]http://i.imgur.com/IVNdt.png [3]http://i.imgur.com/mJ1ZD.png [4]http://i.imgur.com/Xu

Thanks! I encountered Ngaro shortly after I started designing Mako. Aside from I/O functionality they are fairly similar, but I think storing the stacks and registers in addressable memory is a more flexible design than keeping them separate as Ngaro does. For one thing it means it's possible to remap the stacks at runtime and easily implement cooperative multitasking.[1] Games of the type I'm writing don't really need Ngaro's file I/O capabilities, but they could be very useful if I wanted to make a bootstrapped version of my Forth compiler. Trying to recompile Ngaro bytecode to run on Mako could be an interesting weekend project... [1] https://github.com/JohnEarnest/Mako/blob/master/examples/Thr...