Unicorn Sparkle Basic

Unicorn Sparkle Basic, or usbasic, is a simple command-line BASIC dialect for pedagogical and recreational use, written in C for maximum portability.

Like many BASICs of yore, usbasic functions simultaneously as:

• an interpreted, line-oriented programming language and runtime
• an editor
• a debugger

Consequently, usbasic can be used standalone to teach and explore many programming principles interactively.

Unlike historical BASICs, usbasic is relatively free of quirks and idiosyncrasies, and has no special graphical mode. The use of emojis, however, is highly recommended, as they are now widely supported by terminal emulators.

Unlike any BASIC I've seen, line numbers are floating point numbers, because it makes complete sense and it's been impossible to convince myself otherwise.

I wrote this language because I wanted a BASIC with these properties to teach my children with, and I couldn't find one.

Build and Run

Building requires GNU make, flex, and bison. With these installed, run make to produce a usbasic executable.

Implementation

• Program organization: Floating-point line numbers (double), with line code stored as an AST in an AVL tree.
• Editing: line-oriented, with readline niceties.
• Data model: Doubles, mutable strings, arrays. Garbage collected (mark-and-sweep).
• Library: basic math, string manipulation, array operations.
• Case-sensitive variables.
• Control flow: if/then/else, goto, gosub/return
• Debugging: Ctrl-C pauses execution.

License

Unicorn Sparkle Basic is released under CC0 1.0 Universal License. See LICENSE.txt file or https://creativecommons.org/publicdomain/zero/1.0/ for full license.