language A fully integrated
Haskell programming
environment. It provides tightly coupled interactive editing,
programs. Two major modes of compilation, correspond to
Lisp's traditional "interpreted" and "compiled" modes.
Compiled and interpreted modules may be freely mixed in any
combination.
Yale Haskell is run using either a command-line interface or
Using the Emacs interface, simple two-keystroke commands
evaluate expressions, run dialogues, compile
modules, turn
specific compiler diagnostics on and off and enable and
disable various
optimisers. 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.
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. A
Macintosh version of Yale Haskell includes
its own integrated programming environment, complete with an
Yale Haskell is a complete implementation of the Haskell
language, but also contains a number of extensions, including:
(1) Instead of 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.
user extensible manner.
(4) A number of small Haskell 1.3 changes have been added,
expression to denote
bottom. Although the 1.3 report is not
yet complete, these changes will almost certainly be part of
the new report.
(6) A number of
annotations are available for controlling
the optimiser, including those for specifying both function
functions, and specialising
over-loaded functions. Many
standard
prelude functions have been specialised for better
performance using these annotations.
modules) is supported using a notion of a UNIT file, which
is a kind of localised
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 (
GHC) and Chalmers (
HBC) 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.)
it is possible to build the system on virtually any system
that runs one of a number of
Common Lisp implementations:
have adaquate performance for our compiler. The current
version is 2.1.
(1993-07-14)