bens / ddc

The Disciplined Disciple Compiler

The Disciplined Disciple Compiler 0.4.3

RELEASE NOTES 06/09/2016

DDC is a research compiler used to investigate program transformation in the presence of computational effects. This is a development release. There is enough implemented to experiment with the language, but not enough to solve actual problems... (unless you're looking for a compiler to hack on).

DDC compiles several related languages:

• Disciple Tetra (.ds)

  An implicitly typed strict functional language with region and effect typing. Uses effect reification (box) and reflection (run) casts to compose computations with differing effects. Effectful computations are classified by the S e a type, for some effect e and return type a. Although type inference is supported, one can also write explicit type abstractions and applications when needed. Higher ranked types are supported with annotations.

  Example AlmostPrimes program and its output.

  Example GrayCode program and its output.

  The List.ds, and Streams.ds library modules.

• Disciple Core Tetra (.dct)

  The desugared version of Disciple Tetra. All function application is in prefix form. This language also supports type inference, though the inferencer does not insert additional type quantifiers.

• Disciple Core Flow (.dcf)

  Application specific language with built-in support for Series expressions and Data Flow Fusion. This language and its associated transforms is used by the repa-plugin available on Hackage.

• Disciple Core Salt (.dcs)

  A fragment of Disciple Core that can be easily mapped onto C or LLVM code. The Salt language is first-order and does not support partial application. DDC transforms the higher level languages onto this one during code generation, though we can also write programs in it directly.

All core languages share the same abstract syntax tree (AST), type inferencer, and are amenable to many of the same program transformations. They differ only in the set of allowable language features, and which primitive types and operators are included.

Installation

You need a recent version of GHC, and an LLVM suite 3.5 - 3.8 in your path. Easiest way to build is from Hackage.

 cabal update
 cabal install ddc-tools

If you want to build from the git repo then see the wiki.

Main changes since 0.4.3

• Added desugaring of nested patterns and guards.

• Better type inference and desugaring for higher ranked types, which allows dictionaries for Functor, Applicative, Monad and friends to be written easily.

• Automatic insertion of run and box casts is now more well baked.

• Added code generation for partial applications of data constructors.

• Added support for simple type synonyms.

• Changed to Haskell-style syntax for lambda expressions.

• Automatic interrogation of LLVM compiler version, and generation of matching LLVM assembly syntax.

What works in this release

• Compilation for the Tetra, and Salt languages.

• Type checking and data flow fusion for the Flow language.

• Program transformations: Anonymize (remove names), Beta (substitute), Bubble (move type-casts), Elaborate (add witnesses), Flatten (eliminate nested bindings), Forward (let-floating), Namify (add names), Prune (dead-code elimination), Snip (eliminate nested applications), Rewrite rules, cross-module inlining.

What doesn't

• No storage management. There is a fixed 64MB heap and when you've allocated that much space the runtime just calls abort().

Previous Releases

• 2016/04 DDC 0.4.2: Added code generation for higher order functions.
• 2014/03 DDC 0.4.1: Added bi-directional type inference and region extension.
• 2013/07 DDC 0.3.2: Added Tetra and Flow language fragments.
• 2012/12 DDC 0.3.1: Added Lite fragment, compilation to C and LLVM.
• 2012/02 DDC 0.2.0: Project reboot. New core language, working interpreter.
• 2008/07 DDC 0.1.1: Alpha compiler, constructor classes, more examples.
• 2008/03 DDC 0.1.0: Alpha compiler, used dependently kinded core language.

Immediate Plans

1. Implement garbage collection.

2. Implement basic name spacing.

How you can help

1. Work through the tutorial on the web-site and send any comments to the mailing list.

2. Say hello on the mailing list and we can help you get started on any of the main missing features. These are all interesting projects.

3. Tell your friends.

More Information

See the web-site: http://disciple.ouroborus.net

Read the mailing list: http://groups.google.com/group/disciple-cafe

Check the blog: http://disciple-devel.blogspot.com.au/