LtU now supports Mathjax

LtU now supports MathJax, which allows the use of TeX markup in posts and comments. Note that only TeX/LaTeX markup is currently supported - the alternate MathML format conflict's with the blog's HTML sanitization.

This enhancement is dedicated to neelk, who most recently suggested this feature just over a year ago.

When I went searching for a bit of Mathjax-compatible LaTeX that was relevant to programming languages, the first good example Google found for me was on Neel's blog:

\newcommand{\judge}[3]{{#1} \vdash {#2} : {#3}}
\newcommand{\letv}[3]{\mathsf{let}\;{#1} = {#2}\;\mathsf{in}\;{#3}}
\rule{\judge{\Gamma}{e}{T(A)} \qquad
\judge{\Gamma, x:A}{e'}{T(C)}}

Copy-pasting the above and making it work immediately made it clear that we're going to need a package of useful macros. But it's a start. Feedback welcome.

Note that MathJax rendering is entirely client-side - if you don't see a well-formatted formula above, check the MathJax browser compatibility page and their FAQ.

The broad ML Family workshop

It is not generally proper to post call-for-papers on LtU. Exceptions have been made, for broad workshops likely to appeal to many LtU readers. I hope the 2014 ML Family workshop also qualifies.

The ML Family workshop intends to attract the entire family of ML languages, whether related by blood to the original ML or not. Our slogan is ``Higher-order, Typed, Inferred, Strict''. Designers and users of the languages fitting the description have many issues in common, from data representation and garbage collection to fancy type system features. As an example, some form of type classes or implicits has been tried or been looked into in several languages of the broad ML family. We hope the ML Family workshop is a good forum to discuss these issues.

Also new this year is a category of submissions -- informed opinions -- to complement research presentation, experience reports and demos. We specifically invite arguments about language features, be they types, garbage collection, implicits or something else -- but the arguments must good and justified. Significant personal experience does count as justification, as do empirical studies or formal proofs. We would be delighted if language implementors or long-time serious users could tell, with examples from their long experience, what has worked out and what has not in their language.

The deadline for submitting an abstract of the presentation, up to 2 PDF pages, is in a month. Please consider submitting and attending!

F# compiler, library and tools now open for community contribution

F# is the first MS language to go open source. The F# team is now going further into the Open World to allow community contributions to the core language, library and tool set. This means the F# team will now take pull requests :)

From a recent blog post on the topic:

"Prior to today (April 3, 2014), contributions were not accepted to the core implementation of the F# language. From today, we are enabling the community to contribute to the F# language, library and tools, and to the Visual F# Tools themselves, while maintaining the integrity and unity of the F# language itself.

In more detail:
•Contributions can now be made to the core F# compiler, library and tools implementation.
•Proposed changes will be rigorously moderated by ourselves and other community contributors from Microsoft Research and the F# community.
•The full tests for the F# compiler and library are now available.
•In time, the full source code and test suite for the Visual F# Tools will be made available."

.NET Compiler Platform ("Roslyn")

The .NET Compiler Platform (Roslyn) provides open-source C# and Visual Basic compilers with rich code analysis APIs. You can build code analysis tools with the same APIs that Microsoft is using to implement Visual Studio!

In a nutshell: OPEN SOURCE C# COMPILER. Putting aside possible practical implications of this for the .NET ecosystem, I think it is good for programming language geeks to be able to peruse the source code for compilers and language tools.

For the debate about MS being evil, you can head directly to HN where you'll also find an explanation of what bootstrapping a compiler means.

Future of Programming workshop

The call for submissions is out. There will be two opportunities this first year to participate: at Strangeloop in September and at SPLASH in October. The call:

We are holding two events. First, in partnership with the Emerging Languages Camp, FPW×ELC will be at Strange Loop on September 17 in St. Louis MO. Second, at SPLASH in Portland OR around Oct. 19 (pending approval).

We want to build a community of researchers and practitioners exploring the frontiers of programming. We are looking for new ideas that could radically improve the practice of programming. Ideas too embryonic for an academic paper yet developed enough to demonstrate a prototype. Show us your stuff!

FPW×ELC will present live demonstrations before an audience. The SPLASH event will be an intense, private writer’s workshop1,2. This process will be a chance to give and take both creative support and incisive criticism.

Submissions will be 15 minute demo screencasts. You can select either or both of the events in your submission. The submission deadline is June 8 and notifications will be sent June 27. After the events participants will have until December 1 to revise their screencasts for archival publication on our website. The submission site is now open. For questions please see the FAQ or ask

Brought to you by Richard Gabriel, Alex Payne, and Jonathan Edwards.

This is a good idea for the more edgy language designers to exhibit their work and receive useful critique to improve presentation, which ultimately helps with our goal of world domination (or at least, pushing the community to take more risks).

Functional Geometry and the Traite ́ de Lutherie

Functional Geometry and the Traite ́ de Lutherie by Harry Mairson, Brandeis University.

We describe a functional programming approach to the design of outlines of eighteenth-century string instruments. The approach is based on the research described in Francois Denis’s book, Traite ́ de lutherie. The programming vernacular for Denis’s instructions, which we call functional geometry, is meant to reiterate the historically justified language and techniques of this musical instrument design. The programming metaphor is entirely Euclidean, involving straightedge and compass constructions, with few (if any) numbers, and no Cartesian equations or grid. As such, it is also an interesting approach to teaching programming and mathematics without numerical calculation or equational reasoning.

The advantage of this language-based, functional approach to lutherie is founded in the abstract characterization of common patterns in instrument design. These patterns include not only the abstraction of common straightedge and compass constructions, but of higher-order conceptualization of the instrument design process. We also discuss the role of arithmetic, geometric, harmonic, and subharmonic proportions, and the use of their rational approximants.

Study finds that when no financial interests are involved programmers choose DECENT languages

For immediate release. By studying the troves of open source software on the github service, a recent (and still unpublished) study by a team of empirical computer scientists found that programmers prefer to use DECENT languages. DECENT languages were defined by the team to be languages that conform to a set of minimal ethical standards, including clean syntax, expressive type systems, good package managers and installers, free implementations, no connection to the military-industrial complex and not harming animals. The researchers argue that their data support the view that the prevalent use of indecent languages, Java in particular, is the result of money influencing programmer decisions. The principal author of the study notes that DECENT languages do not necessarily make the most MORAL choices (e.g., many of them are not statically typed). He attributed this to a phenomenon called the "weakness of the will."

Details to follow.

Brendan Eich, CEO of mozilla

Correct me if I'm wrong, but I think this is the first case of a language designer making it to the top slot of a company!

Facebook Introduces ‘Hack,’ the Programming Language of the Future

From Wired, Facebook Introduces ‘Hack,’ the Programming Language of the Future

You can think of Hack as a new version of PHP. It too runs on the Hip Hop Virtual Machine, but it lets coders use both dynamic typing and static typing. This is what’s called gradual typing, and until now, it has mostly been an academic exercise. Facebook, O’Sullivan says, is the first to bring gradual typing to a “real, industrial strength” language.

Hack is open source and is available at It supports type annotation, generics, lambdas and host of other features on top of PHP.

The Essence of Reynolds

The Essence of Reynolds by Stephen Brookes, Peter O'Hearn and Uday Reddy.

John Reynolds (1935-2013) was a pioneer of programming languages research. In this paper we pay tribute to the man, his ideas, and his influence.

Corresponding presentation from POPL.