Programatica Haskell Tools

It should also be possible for Haskell programmers to reuse our Haskell front-end in their own Haskell programs, but at the moment there is very little documentation to support this, unfortunately. (But it has been used in HaRe -- the Haskell refactorer tool from the University of Kent.)

Summary of functionality

Supported language

The tools support Haskell 98 as described in the Haskell 98 Language and Libraries: the Revised Report. It also supports a number of extensions to varying degree.

Unusually well-supported standard language features

Mutually recursive modules (without the need for hi-boot files). (See our formal module system specification from the Haskell Workshop in 2002.)
A lexer that complies with the Haskell report. (See the Lexer for Haskell in Haskell page.)

Common Haskell Language extensions

Available functionality: P=lexing/parsing/scoping, T=type checking
Y=supported, y=partially supported, n=not supported (yet), blank=n/a.
P	T	Feature
Y		Hierarchical module names (i.e. "`.`" in module names)
Y	y	Haskell Hierachical Libraries
y		Foreign Function Interface
Y	Y	Multi-parameter classes
Y	Y	Overlapping instances (as in Hugs)
Y	y	Functional dependencies (see Type Classes with Functional Dependencies)
Y	n	Rank-n polymorphism (use of the `forall` keywords in type expression)
Y	n	Existentially quantified types (use of the `forall` keyword in data constructor specifications)
Y	Y	The horrible n+k patterns
n	n	Pattern guards
n	n	Infix type constructors
n	n	Type signatures in patterns, scoped type variables
y	n	Generalised derived instances for newtypes
n	n	Generalised Algebraic Data Types
n	n	`mdo`

Programatica specific language extensions

Predicate definitions, using the property keyword.
Property assertions, using the assert keyword.
P-logic formulas (appear in predicate definitions and property assertions).
A special comment syntax that can be used to mark assertions and other code that should be considered by the Programatica tools, but ignored by Haskell compilers: {-P: ... -}.

Supported Libraries

The command pfesetup sets up a project using the Haskell 98 libraries by default. By supplying the flag +h or hierarchical a project using the hierarchical libraries is created instead.

Limitations

The tools currently don't implement exhaustive checking for static errors and might let things like duplicate definitions or repeated variables in patterns slip through silently. (Implementing this has been given low priority, since it has been assumed that the tools will be used as a complement to other Haskell compilers/interpreters, rather than a replacement.)