BitC

Infobox Software
name = BitC
author = Jonathan S. Shapiro, Swaroop Sridhar, and M. Scott Doerrie
developer = Johns Hopkins University, [http://www.eros-os.com The EROS Group, LLC]
released =
latest release version = BitCC 0.9.1
latest release date = February 17, 2006
latest preview version = BitC 0.10.1
latest preview date = June 17, 2006
operating system = Cross-platform
platform =
language =
genre = Compiler
license = BSD
website = http://www.bitc-lang.org/

BitC is a programming language currently being developed by researchers [http://www.bitc-lang.org/people.html] at the Johns Hopkins University and [http://www.eros-os.com The EROS Group, LLC] , as part of the Coyotos project. The language has two primary objectives:

# To merge the advances of modern programming languages; sound type systems with abstraction, sound and complete type inference, let-polymorphism, and mathematically grounded semantics — with the requirements of systems programming; first-class treatment of state, support for prescriptive low-level representation, explicitly unboxed types, and performance comparable to C.
# Eventually, to support formal program verification of low-level systems programs, such as kernels/microkernels.

It is an innovative language in that it combines the concepts higher-order functional programming languages like ML and Haskell with the close hardware interaction of low-level programming languages like C. The current language syntax is derived from the syntax Lisp, but this is expected to be replaced as the language comes to its first release.

From the standpoint of programming language evolution, BitC's most important innovation is the first sound and complete type inference algorithm that handles generalized state and unboxing. With the recent (not yet implemented) addition of effect typing, Bitc presents an interesting middle position between purely functional and traditionally state-oriented languages.

From the perspective of systems programmers, BitC may be more interesting for the fact that the non-optimizing research prototype compiler is delivering performance on early benchmarks that falls within 1% to 1.5% of C on comparable codes.

History

The goals for the BitC language were set out in 2004 in "Towards a Verified, General-Purpose Operating System Kernel" ( [http://www.coyotos.org/docs/osverify-2004/osverify-2004.html html] , [http://www.coyotos.org/docs/osverify-2004/osverify-2004.pdf pdf] ) presented at the [http://www.cse.unsw.edu.au/~formalmethods/events/os-verify-04/ 2004 NICTA OS Verification Workshop] . Some details of the origins and early evolution of the language can be found in "The Origins of the BitC Programming Language" ( [http://www.bitc-lang.org/docs/bitc/bitc-origins.html html] , [http://www.bitc-lang.org/docs/bitc/bitc-origins.pdf pdf] ).

In 2006, Shapiro left Johns Hopkins to form The EROS Group, LLC, and the BitC project became a joint effort between the two organizations.

As the end of 2008 approaches, the specification for the first released version of the language and its compiler is converging rapidly into its final form, and the prototype compiler has demonstrated favorable performance on microbenchmarks.

Jonathan S. Shapiro has been a driving force behind both BitC [http://www.bitc-lang.org] and Coyotos [http://www.coyotos.org/history.html] .

tatus

BitC is currently under simultaneous development with the main Coyotos project. An early compiler for BitC, known as BitCC, was first released in an alpha form (v. 0.10.1) on June 17, 2006.

External links

* [http://www.bitc-lang.org/ BitC homepage]
* "BitC Language Specification" ( [http://www.bitc-lang.org/docs/bitc/spec.html html] , [http://www.bitc-lang.org/docs/bitc/spec.pdf pdf] )
* [http://www.coyotos.org/pipermail/bitc-dev/ BitC-dev mailing list archives]
* [http://www.coyotos.org/ Coyotos homepage]
* [http://srl.cs.jhu.edu/~shap/ Jonathan Shapiro's homepage]