294 papers · page 10 of 15
Adequate encodings are a powerful programming tool, which eliminate whole classes of program bugs: they ensure that a program cannot generate ill-formed data, because such data is not part of the representation; and they also ensure that a program is well-defined, meaning that it…
This paper shows how call-by-need supercompilation can be recast to be based explicitly on an evaluator, contrasting with standard presentations which are specified as algorithms that mix evaluation rules with reductions that are unique to supercompilation. Building on standard o…
The functional programming languages Clean and Haskell have been around for over two decades. Over time, both languages have developed a large body of useful libraries and come with interesting language features. It is our primary goal to benefit from each other's evolutionary re…
We present a concurrent scripting language embedded in Haskell, emulating the functionality of the Orc orchestration language by providing many-valued (real) non-determinism in the context of concurrent effects. We provide many examples of its use, as well as a brief description …
Haskell's deriving mechanism supports the automatic generation of instances for a number of functions. The Haskell 98 Report only specifies how to generate instances for the Eq, Ord, Enum, Bounded, Show, and Read classes. The description of how to generate instances is largely in…
We describe Nikola, a first-order language of array computations embedded in Haskell that compiles to GPUs via CUDA using a new set of type-directed techniques to support re-usable computations. Nikola automatically handles a range of low-level details for Haskell programmers, su…
We present a complete redesign of evaluation strategies, a key abstraction for specifying pure, deterministic parallelism in Haskell. Our new formulation preserves the compositionality and modularity benefits of the original, while providing significant new benefits. First, we in…
Hackage, an online repository of Haskell applications and libraries, provides a hub for programmers to both release code to and use code from the larger Haskell community. We suggest that Hackage can also serve as a valuable resource for language designers: by providing a large c…
We have developed a new, portable I/O event manager for the Glasgow Haskell Compiler (GHC) that scales to the needs of modern server applications. Our new code is transparently available to existing Haskell applications. Performance at lower concurrency levels is comparable with …
Shared Term Graph (STG) is a lazy functional language used as an intermediate language in the Glasgow Haskell Compiler (GHC). In this article, we present a natural operational semantics for STG and we mechanically derive a lazy abstract machine from this semantics, which turns ou…
Dataflow analysis and transformation of control-flow graphs is pervasive in optimizing compilers, but it is typically entangled with the details of a particular compiler. We describe Hoopl, a reusable library that makes it unusually easy to define new analyses and transformations…
Parsers and pretty-printers for a language are often quite similar, yet both are typically implemented separately, leading to redundancy and potential inconsistency. We propose a new interface of syntactic descriptions, with which both parser and pretty-printer can be described a…
In this paper, we perform a thorough performance analysis of the containers package, the de facto standard Haskell containers library, comparing it to the most of existing alternatives on HackageDB. We then significantly improve its performance, making it comparable to the best i…
In the presence of ever-changing computer architectures, high-quality optimising compiler backends are moving targets that require specialist knowledge and sophisticated algorithms. In this paper, we explore a new backend for the Glasgow Haskell Compiler (GHC) that leverages the …
The theory of combinatorial species, although invented as a purely mathematical formalism to unify much of combinatorics, can also serve as a powerful and expressive language for talking about data types. With potential applications to automatic test generation, generic programmi…
Even Haskell programs can occasionally go wrong.Programs calling head on an empty list, and incomplete patterns in function definitions can cause program crashes, reporting little more than the precise location where error was ultimately called.Being told that one application of …
Higher-order abstract syntax provides a convenient way of embedding domain-specific languages, but is awkward to analyse and manipulate directly. We explore the boundaries of higher-order abstract syntax. Our key tool is the unembedding of embedded terms as de Bruijn terms, enabl…
No abstract available.
Structured documents are commonly edited using a free-form editor. Even though every string is an acceptable input, it makes sense to maintain a structured representation of the edited document. The structured representation has a number of uses: structural navigation (and option…
It is common for compilers to derive the calling convention of a function from its type. Doing so is simple and modular but misses many optimisation opportunities, particularly in lazy, higher-order functional languages with extensive use of currying. We restore the lost opportun…