HBL: Half-Byte Lisp

HBL is a Lisp dialect designed for code golf. It uses a codepage with 16 characters, meaning that two characters can be encoded in a single byte. HBL also comes with an ungolfed mode called Thimble.

Getting started

The easiest way to try HBL is in the online interpreter.

HBL is implemented in Scala 3. If you have Scala 3 with the sbt build tool installed, you can use the following steps to run HBL code:

• Clone the HBL repository
• At the command line, navigate to the repository's root directory
• Run sbt
• Once the sbt server has started up, type run path/to/hblfile args at the sbt prompt to run the given HBL program with the given arguments

For example, you can run the Collatz function example program with an input of 7 by typing run examples/collatz.hbl 7. To pass a list as an argument, wrap it in quotes: "(1 2 3)".

The format of a code file is determined by its extension:

• .hb indicates packed HBL code, a binary file with each byte representing two codepage characters. You may find a hex editor helpful.
• .hbl indicates HBL code in plain text format with each codepage character represented by one byte of ASCII.
• .thbl indicates Thimble code in plain text format.

Running with Java

If you have Java installed, you can run HBL directly from a JAR file without any Scala dependencies:

• Download the JAR file from the latest release
• At the command line, navigate to the directory where the JAR file is
• Run java -jar hbl-a.b.c.jar path/to/hblfile args to run the given HBL program with the given arguments

Thanks to cgccuser for figuring out how to package the application in JAR format.

Documentation

Documentation for HBL and Thimble can be found in the docs folder of this repository.