CodeArchaeology

π ('a pattern language') is a research language from Roman Knöll and Mira Mezini's Software Technology Group at TU Darmstadt in which the only construct is the pattern: an EBNF-style syntax rule with an attached meaning, declared at run time and immediately usable as if it had always been part of the language. Grown out of the Pegasus naturalistic-programming project, presented in the Onward! track of OOPSLA 2009 in Orlando and released as a Java-based interpreter (the last announced version, 0.8, in January 2010), it aimed to be a language that is fully syntactically and semantically extensible from within itself - a language-design tool as much as a programming language. Its website has not changed since mid-2011

Pico is a tiny, dynamically typed, statically scoped 'Scheme for mere mortals' designed by Theo D'Hondt at the Programming Technology Lab of the Vrije Universiteit Brussel to teach programming to first-year physics, chemistry, mathematics and biology students. It keeps Scheme's first-class-everything semantics (closures, continuations, reified programs, garbage collection) but replaces prefix notation with calculus-style infix syntax, replaces pairs with tables (arrays), and replaces special forms with an unusual call-by-function parameter-passing rule. Prototyped in Scheme in 1995 and re-implemented as an ANSI C virtual machine in 1997, it went on to serve as the substrate for VUB research languages such as Pic%, Borg and, indirectly, AmbientTalk. The last known release is a Linux packaging from January 2014

ParaSail (Parallel Specification and Implementation Language) is S. Tucker Taft's pointer-free, pervasively parallel object-oriented language: every parameter, every operand of an expression and every iteration of a for loop is evaluated in parallel unless the program says otherwise, and the compiler rejects any code where that could produce a race. Designed in public on a blog from September 2009, first released as an alpha interpreter in October 2011 by Taft's company SofCheck and carried on at AdaCore after the two merged in January 2012, it grew an LLVM compiler written in ParaSail itself, a static analyser, and sibling front ends (Sparkel, Javallel, Parython and an Ada 202X prototype) that share its virtual machine. The last packaged release was 9.3 in June 2021; the sources moved to GitHub in 2022 and still receive occasional commits

Parrot is the register-based virtual machine that grew out of the Perl 6 project: born in August 2001 from an April Fools' joke about Perl and Python merging, designed by Dan Sugalski to run every dynamic language on one runtime, and the platform Rakudo Perl 6 ran on for its first seven years. Its more than a hundred monthly releases from 2006 to 2016, its Parrot Design Documents, and its compiler toolkit (PGE, PCT and NQP) shaped Perl 6 far more than its bytecode ever did; MoarVM replaced it as Rakudo's runtime in 2015, the last supported release was 8.1.0 in February 2016, and the project posted an inactivity notice in August 2021 - though its last release manager was still committing fixes in December 2025

A comprehensive catalog of 1,200+ programming languages from computing history, with dates, status, paradigms, and categories.

Nit is the statically typed, self-hosting object-oriented language that Jean Privat grew out of his PRM research compiler at LIRMM and has led since 2008 at UQAM in Montreal - a Pascal-and-Ruby-flavoured language in which everything is an object, classes inherit from several parents, any module can reopen and refine any class (even Int), types are flow-sensitive and nullable-aware, generics are covariant, and a compiler-to-C toolchain reaches Linux, macOS, Android, iOS and emscripten - first released under the Nit name on 9 July 2008, last released as v0.8 on 31 January 2016, and still receiving occasional commits in 2024 and 2026