There is life beyond C++! Here are some oddball programming languages and utilities that I've managed to compile for Haiku. Mostly for geekish amusement, but you could actually write CLI utilities with them.
aria_lang - A tiny, embeddable lisp-shaped language
bas - Michael Haardt's BASIC dialect, plus Paul Wratt's version and my own Haiku-specific routines.
bas55 - An ECMA-55 compatible BASIC interpreter
Basenji - PRE-RELEASE! A BASIC dialect, and a set of libraries to extend the language for the Haiku environment.
basick - BASIC implemented in python lua, ruby and php
Beta-Juliet - A minimal event-oriented language
bf - Brainfuck interpreters (sorry, but that's what it is called).
bleach - A language to teach programming language design
bogusforth - An obfuscated programming language
Bywater BASIC - An old classic interpreter
ccsh - Use C as a scripting language
deheader - Find unnecessary headers in C/C++ source code
harbour - A database language, backward compatible with Clipper/xBase
hoedown - A Markdown parser
Fe - A tiny, embeddable language
FreeBASIC - FreeBASIC for Haiku
Lang5 - An array (functional) language
magma - An alternative C++ build system
Muon - A modern low-level programming language, inspired by C, C#, Go, Rust and Python.
pocketlang - A lightweight, fast embeddable scripting language
rascal - A simple Pascal interpreter.
realforth - 16 bit Forth for PC. No OS required.
scidown - Markdown parser and HTML and LaTeX generator
shbasic - Convert BASIC to Pascal
Tab - A programming language/shell calculator
ToyBASIC - A small project to learn how an interpeter is written in FreeBASIC
wsbasic - A BASIC interpreter
Yabasic - A BASIC dialect