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*** Announcing the Latest and Greatest Release of Yale Haskell ***
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Yale Haskell 2.1 has many significant new features and improvements,
including substantially improved compiled code. Thus we'd like to
take this opportunity to briefly describe the entire system rather
than give an incremental status report.
The Yale Haskell system is a fully integrated Haskell programming
environment. It provides tightly coupled interactive editing,
incremental compilation, and dynamic execution of Haskell programs.
Two major modes of compilation, corresponding to Lisp's traditional
"interpreted" and "compiled" modes, allow one to rapidly develop
software (using the interpreted mode), saving performance gains till
the software has stabilized (using the compilation mode). Compiled
and interpreted modules may be freely mixed in any combination.
Yale Haskell is run using either a command-line interface or as an
inferior process running under the Emacs editor. Using the Emacs
interface, simple two-keystroke commands evaluate expressions, run
dialogues, compile modules, turn specific compiler diagnostics on and
off, enable and disable various optimizers, etc. Commands may be
queued up arbitrarily, thus allowing, for example, a compilation to be
running in the background as the editing of a source file continues in
Emacs in the foreground.
In addition, to further enhance incremental compilation, a "scratch
pad" may be automatically created for any module. Such a pad is a
logical extension of the module, in which additional function and
value definitions may be added, but whose evaluation does not result
in recompilation of the module.
A tutorial on Haskell is also provided in the Emacs environment.
It follows the Sigplan Notices Hudak/Fasel "Gentle Introduction"
section-by-section, and encourages user interaction. This is a very
popular teaching device for novice users.
We also support a Macintosh version of Yale Haskell that includes its
own integrated programming environment, complete with an Emacs-like
editor, pull-down menus, etc.
Yale Haskell is a complete implementation of the Haskell language, but
also contains a number of extensions, including:
(1) Instead of the old-style stream based I/O, a monadic I/O system is
used. Although similar to what will be part of the new Haskell 1.3
report, the I/O system will change yet again when 1.3 becomes official.
(2) Haskell programs can call both Lisp and C functions using a
flexible foreign function interface.
(3) Yale Haskell includes a dynamic typing system. Dynamic typing has
been used to implement derived instances in a user extensible manner.
(4) A number of small Haskell 1.3 changes have been added, including
polymorphic recursion and the use of @_@ in an expression to denote
bottom. Although the 1.3 report is not yet complete, these changes
will almost certainly be part of the new report.
(5) A complete X window interface, based on the CLX system, is included.
(6) A number of annotations are available for controlling the optimizer,
including those for specifying both function and data constructor
strictness properties, "inlining" functions, and specializing
over-loaded functions. Many standard prelude functions have been
specialized for better performance using these annotations.
(7) Separate compilation (including mutually recursive modules) is
supported using a notion of a UNIT file, which is a kind of localized
makefile that tells the compiler about compiler options and
logical dependencies amongst program files.
(8) Yale Haskell supports both standard and "literate" Haskell syntax.
Performance of Yale Haskell's compiled code has been improved
considerably over previous releases. Although still not as good as
the Glasgow and Chalmers compilers, the flexibility afforded by the
features described earlier makes Yale Haskell a good choice for large
systems development. For some idea of performance, Hartel's latest
"Nuc" benchmark runs at about the same speed under both Yale Haskell
and hbc. (Our experiments suggest, however, that Yale Haskell's
compiled code is on average about 3 times slower than hbc.)
The Yale Haskell systems is available on a number of popular systems;
binaries are provided for Sun/Sparc and Macintosh, but it is possible
to build the system on virtually any system that runs one of a number
of Common Lisp implementations. We do NOT support either akcl (gcl)
or CLisp; these systems do not have adaquate performance for our
compiler. See the manual for details.
Our system is available for anonymous ftp from the Yale Haskell ftp
site: (other Haskell ftp sites may also have these files)
Site Host name Raw IP address
Yale nebula.cs.yale.edu 128.36.13.1
All files are in the directory pub/haskell/yale. Consult the README
in this directory for further details.
To obtain Yale Haskell via ftp:
- Move to the directory where you intend to place Yale Haskell
- Ftp to nebula and login anonymously
- cd to pub/haskell/yale
- Get the tar file: get haskell-2.1-?.tar.gz
- Unzip the file: (your zip utility may have a different name)
gzip -d *.gz
- Untar the file: tar xf *.tar
- Consult the documentation for further instructions. The manual
is provided in Postscript form as doc/manual/haskell.ps.
Please send any comments or questions to [EMAIL PROTECTED]
