Taxon

Applying the safety and extensibility of programming to hands-on making.

About

The code for Taxon comprises server and client code to run the Taxon interface in a web browser. Server-side code reads from the program_database/ directory and loads the parts of Taxon programs into a database. Client-side code renders the interface, pulls Taxon programs from the server, and compiles programs to a scene. Users can then load different workflows and rules of thumb. The recommended way to add or edit programs is by editing the files in program_database/ rather then making edits in the browser.

Installation

Installation consists of three parts: running a MongoDB instance which is required by the server, then installing dependencies, and running the server itself.

Running MongoDB

You must run a MongoDB instance locally to use Taxon. Cloud-based instances are not yet available (sorry!). Follow instructions here to install MongoDb. Then, run a MongoDB instance e.g. on a Mac with: mongod --dbpath=~/data, which uses your home directory as the data directory. Make sure line the server URL line in server.js matches the current MongoDB instance, e.g.

const url = 'mongodb://127.0.0.1:27017/';

You may have to edit the address to port to match your instance.

Installing Dependencies

1. Clone the repository.
2. Install Node.js and NPM if they are not already installed.
3. Run npm install.

Running the Server

1. Ensure that you have a MongoDB instance running!
2. Run node server. Alternatively, install Nodemon and run nodemon server to reload the server whenever any source files are edited, which is very handy for writing new Taxon programs.
3. Navigate to localhost:3000 in your favorite browser.

Writing Taxon Programs

Taxon programs (examples can be found in program_database/), with several subdirectories:

• machine_plans/ JSON files containing the metrics and blocks of each machine.
• workflows/ JSON files containing arrays of actions as strings.
• rules_of_thumb/ each rule of thumb has a JSON metadata file and a JS file of the same name that contains the Javascript implementation.
• parts/: part of future work, do not use it right now.

Whenever you run node server, the server code will drop the current database, look at every .json file (Taxon program) in machine_programs/ and parse every file and add it to the database. If you want to turn this behavior off, set the line in server.js

const DO_SEED_DATABASE = true;

to false.

If there are any syntax errors in any of the JSON files, the server will print a humongous error message. To add a new Taxon program, I recommend making a new file with the top-level structure as indicated above. Then, copy and paste blocks, motors, etc. from an existing file into the new file, and restart the server and load the new machine in the browser to see the results. It's unfortunately not at all the fastest way to write programs right now, but futher composition tools and error checking for wellformedness of Taxon programs is forthcoming.

Known Issues

• Currently, kinematics calculation for machines with moving platforms is not currently working correctly when it comes to extruding material. We were not able to fix this before the deadline. If you want to use a workflow that extrudes material (second argument of $machine.moveTo(coords, extrude) is not empty) after having used a machine with a moving platform, then you need to refresh the page first.
• If you get an error message in the console that looks like a Javascript error message, open up the web browser console to investigate what the issue is.