Lambda the Ultimate

If you are interested in the intersection of PL and computer graphics, I invite you to read our SIGGRAPH paper on Spark, a real-time shading language that aims to improve support for good software engineering practice. From the abstract:

In creating complex real-time shaders, programmers should be able to decompose code into independent, localized modules of their choosing. Current real-time shading languages, however, enforce a fixed decomposition into per-pipeline-stage procedures. Program concerns at other scales - including those that cross-cut multiple pipeline stages - cannot be expressed as reusable modules.

We present a shading language, Spark, and its implementation for modern graphics hardware that improves support for separation of concerns into modules. A Spark shader class can encapsulate code that maps to more than one pipeline stage, and can be extended and composed using object-oriented inheritance. In our tests, shaders written in Spark achieve performance within 2% of HLSL.

You can access the paper through either our Intel or Stanford pages. The Intel page also has a link to the source code for our system.

If you are in Vancouver this week for SIGGRAPH, you can catch my talk on Thursday.

Dear members of LtU,

I'm glad to announce the 0.9.1 beta release of Candle (Common ApplicatioN Development LanguagE). Candle is an open-source (MPL) scripting language that unifies the core features of many XML-related technologies (including XSLT, XQuery, XQuery Update, RELAX NG, BNF, XHTML, SVG and more). It can be used to develop command-line, desktop and Internet applications quickly.

Some of the advantages of Candle comparing to XSLT and XQuery are:

• Candle is an unified language instead of two highly-overlapping languages. Candle uses scripting syntax instead of the highly verbose markup syntax of XSLT.
• Candle's markup language is strongly-typed even without schema, whereas XML is only weakly-typed without schema.
• Candle consists of a pattern language which cleanly unifies several pattern-related DSLs (including RegEx, BNF, RELAX NG, XQuery Sequence Type). It can easily match on sequence of items, nodes and characters.
• Candle unifies functional and procedural programming. Through a mechanism I called separation-of-side-effects, Candle unifies two worlds in a more orderly manner then any existing multi-paradigm programming languages. In Candle, routines are divided into functions and methods. Functions are routines without side-effects and methods are routines with side-effects. The rule of separation-of-side-effects is that methods can call functions, but not vice versa. And expressions in Candle are always functional. In this way, pure functional islands are well-preserved in the vast sea of procedural code.
• Candle is a general-purpose scripting language like Python, whereas XSLT and XQuery are just DSLs. Candle alone is sufficient to develop complex command-line, desktop and Internet applications, whereas XSLT and XQuery still need to integrate with other languages to develop a serious application.

For more information, you can visit the website (http://www.candlescript.org/) or the SourceForge project.

You can also read two blog articles Why I Invented Candle (I), Why I Invented Candle (II) and Towards the Grand Unification to understand the design rationales behind Candle.

Your feedback on Candle is highly appreciated.

Henry

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_{Candle App Platform - An unified platform for desktop and Internet apps.}