The Glasgow Haskell Compiler is a robust, fully-featured, optimising compiler for the functional programming language Haskell. GHC compiles Haskell to either native code or C. It implements numerous experimental language extensions to Haskell for example concurrency, a foreign language interface, several type-system extensions, exceptions, and so on. GHC comes with a generational garbage collector, a space and time profiler, and a comprehensive set of libraries.
Knit is a new component definition and linking language that can be used with C and assembly code. Knit supports component definitions that require little or no modification to existing code. It automatically schedules component initializers and finalizers and provides an extensible constraint system to detect subtle errors in component composition. Knit provides cross-module inlining that largely eliminates the overheads of componentization, supports component hierarchies, and supports cyclic component dependencies. Knit can be used for any C program, but is especially well suited for use in systems that have many separate components, multiple implementations of the same component, intricate initialization requirements, complex component interdependencies, low-level code and embedded systems, or code that is used in radically different configurations.
A practical lambda-calculator is a normal-order evaluator for the untyped lambda-calculus, extended with convenient commands and shortcuts to make programming in it more productive. Shortcuts are distinguished constants that represent terms. Commands define new shortcuts, activate tracing of all reductions, compare terms modulo alpha-conversion, print all defined shortcuts and evaluation flags, etc. Terms to evaluate and commands are entered at a read-eval-print-loop (REPL) "prompt" or "included" from a file by a special command. A Haskell branch is an embedding of the lambda calculator (as a domain-specific language) into Haskell. The calculator can be used interactively within Hugs or GHCi.
Haskell Ports Library provides ports in Haskell. Ports are an abstraction for modelling variables whose values evolve over time without the need to resort to mutable variable, such as IORefs. More precisely, a port represents all values that a time-dependent variable successively take as a stream, where each element of the stream corresponds to a state change. A port supports concurrent construction of the time series, or stream of values. Ports are ideally suited for purely functional GUI interfaces that completely avoid the use of mutable variables.
DrIFT is a type sensitive preprocessor for Haskell. It extracts type declarations and directives from modules and applies rules to them which generate code. It is intended that the user can add new rules as required. DrIFT automates instance derivation for classes that aren't supported by the standard compilers. In addition, instances can be produced in separate modules to that containing the type declaration. This allows instances to be derived for a type after the original module has been compiled. Simple utility functions can also be produced from a type.
hmake is a compilation manager for Haskell programs. It is compiler independent, and liberates the programmer from needing to write Makefiles by extracting dependencies directly from the source code. It is aware of all compiler invocation conventions, and of several common pre-processors, including cpp, greencard, hsc2hs, c2hs, and happy.
HaXml is a suite of libraries and tools for manipulating XML documents in Haskell. It includes a parser, a pretty-printer, a validator, a combinator library for transforming documents, and converters for changing a Haskell datatype into an XML DTD, and for changing an XML DTD into a set of Haskell datatypes. There are also tools for a query language based on XQL.