Brussels / 30 & 31 January 2016



Scripting Language for IO and UI programming

Jancy is a scripting programming language with LLVM back-end. Jancy offers a lot of convenient features for low-level IO (input-output) and UI (user-interface) programming which are not found in mainstream languages (and sometimes, nowhere else). This includes safe pointer arithmetics, high level of source-level and ABI compatibility with C/C++, reactive UI programming, built-in generator of incremental lexers/scanners and a lot more.

Why create yet another programming language? Like, there isn't enough of them already?

I have asked myself these questions hundreds of times, over and over again. I can name dozens of possible arguments against creating a new programming language. I understand all the difficulties a language creator is doomed to face before he can gather any meaningful number of users of the new language. And I still believe that creation of Jancy was justified. The truth is, Jancy was not created just to fix the infamous fatal flaw of other languages (aka, they didn't write it). Of course, the passion to invent was a significant driving force, but there was practical reasoning besides that.

During development of a product called IO Ninja (a universal all-in-one low-level IO debugger) we were looking for a scripting language with the support for safe pointers and safe pointer arithmetics. After not finding one, we basically had a choice of either settling for some existing alternative (like, embedded Python) -- or create a new language tailor-suited for this task. Create it both for ourselves, and for other developers who could be in need for a scripting language really good at handling binary data. Needless to say, we have chosen the later option -- otherwise, you would not be reading this.

Of course, besides featuring safe pointers and safe pointer arithmetics, Jancy offers a long list of other useful features not found in most mainstream languages (and sometimes, nowhere else). So let's outline the distinguishing features of Jancy below. And for those of you wondering what's in a name, Jancy is an acronym: [in-between] Java-and-C/C++.

Design Principles

  • Object-oriented scripting language for IO and UI programming with C-family syntax
  • ABI compatibility with C/C++
  • Automatic memory management via accurate GC
  • LLVM as a back-end

Key Features

  • Safe pointers and pointer arithmetic
  • High level of source compatibility with C
  • Built-in Reactive Programming support
  • Built-in regexp-based generator of incremental lexers/scanners

Other Notable Features

  • Exception-style syntax over error code checks
  • Properties (the most comprehensive implementation thereof)
  • Multicasts and events (including weak events, which do not require to unsubscribe)
  • Multiple inheritance
  • Const-correctness
  • Thread local storage
  • Weak pointers (that do not retain objects)
  • Partial application for functions and properties
  • Scheduled function pointers
  • Bitflag enums
  • Perl-style formatting
  • Hexadimal, binary and multi-line literals


Photo of Vladimir Gladkov Vladimir Gladkov