Haskell Programming Environment

Christian Lindig lindig@eecs.harvard.edu
Wed, 25 Oct 2000 12:27:14 -0400

On Wed, Oct 25, 2000 at 09:03:43AM -0700, Doug Ransom wrote:
> I would like to be able to inspect the type of things easily by hovering my
> mouse over an expression.  As a beginner, I find it hard sometimes to get
> types correct in Haskell since often variables are not declared as a
> specific type.  

Since you are typically dealing with incomplete programs in an editor
this is really tough.  The PSG system was able to generate such
editors and I once saw it for the purely functional language Sample in
action:  you could mark any term with the mouse cursor and ask for its

-- Christian

  author =       "Rolf Bahlke and Gregor Snelting",
  title =        "The {PSG} System: From Formal Language Definitions to
                 Interactive Programming Environments",
  journal =      "ACM Transactions on Programming Languages and
  volume =       "8",
  number =       "4",
  pages =        "547--576",
  month =        oct,
  year =         "1986",
  coden =        "ATPSDT",
  ISSN =         "0164-0925",
  bibdate =      "Sat Jan 06 09:41:04 1996",
  url =          "http://www.acm.org/pubs/toc/Abstracts/0164-0925/20890.html",
  abstract =     "The PSG programming system generator developed at the
                 Technical University of Darmstadt produces interactive,
                 language-specific programming environments from formal
                 language definitions. All language-dependent parts of
                 the environment are generated from an entirely
                 nonprocedural specification of the language's syntax,
                 context conditions, and dynamic semantics. The
                 generated environment consists of a language-based
                 editor, supporting systematic program development by
                 named program fragments, an interpreter, and a fragment
                 library system. The major component of the environment
                 is a full-screen editor, which allows both structure
                 and text editing. In structure mode the editor
                 guarantees prevention of both syntactic and semantic
                 errors, whereas in textual semantic analysis which is
                 based on unification. The algorithm will immediately
                 detect semantic errors even in incomplete program
                 fragments. The dynamic semantics of the language are
                 defined in denotational style using a functional
                 language based on the lambda calculus. Program
                 fragments are compiled to terms of the functional
                 language which are executed by an interpreter. The PSG
                 generator has been used to produce environments for
                 Pascal, ALGOL 60, MODULA-2, and the formal language
                 definition language itself.",
  acknowledgement = ack-pb # " and " # ack-nhfb,
  keywords =     "algorithms; design; documentation; languages; theory;
                 theory and verification and Hybrid editor and
                 unification-based incremental semantic analysis;
  owner =        "manning",
  review =       "ACM CR 8711-0926",
  subject =      "{\bf D.3.4}: Software, PROGRAMMING LANGUAGES,
                 Processors, Compilers. {\bf D.2.3}: Software, SOFTWARE
                 ENGINEERING, Coding, Program editors. {\bf D.2.6}:
                 Software, SOFTWARE ENGINEERING, Programming
                 Environments. {\bf D.3.1}: Software, PROGRAMMING
                 LANGUAGES, Formal Definitions and Theory, Semantics.
                 {\bf D.3.1}: Software, PROGRAMMING LANGUAGES, Formal
                 Definitions and Theory, Syntax. {\bf D.2.3}: Software,
                 SOFTWARE ENGINEERING, Coding, Pretty printers. {\bf
                 F.3.2}: Theory of Computation, LOGICS AND MEANINGS OF
                 PROGRAMS, Semantics of Programming Languages. {\bf
                 F.4.2}: Theory of Computation, MATHEMATICAL LOGIC AND
                 FORMAL LANGUAGES, Grammars and Other Rewriting Systems,
                 Grammar types. {\bf F.4.2}: Theory of Computation,
                 Other Rewriting Systems, Parsing. {\bf I.2.3}:
                 Computing Methodologies, ARTIFICIAL INTELLIGENCE,
                 Deduction and Theorem Proving, Deduction.",

Christian Lindig          Harvard University - DEAS
lindig@eecs.harvard.edu   33 Oxford St, MD 242, Cambridge MA 02138
phone: +1 (617) 496-7157  http://www.eecs.harvard.edu/~lindig/