Brandon S Allbery KF8NH wrote:
On 7/16/10 05:21 , Andy Stewart wrote:
IMO, "haskell interpreter" is perfect solution for samll script job. But
i'm afraid "haskell interpreter" is slow for *large code*, i don't know,
i haven't try this way...
Hugs?
Or you can try implementing (or finding) a SASL interpreter[1]. SASL is
just the untyped[2] lambda calculus with named functions. ADTs are
implemented by function application, greatly simplifying the
compiler/interpreter. On their benchmarks, the version presented in the
paper is competitive with GHCi 6.4 and outperforms Hugs Jan2005.
Interpreting is always slower than compiled code. But how much that
matters is a separate issue. Folks seem to like their Perl, Python,
Ruby,... even for large projects.
[1] Jan Jansen (2005) /Data Types and Pattern Matching by Function
Application/, Proc. 17th IFL.
[2] The version they present in the paper uses the untyped calculus
since their pattern matching doesn't fit in Hindley--Milner. The problem
is the need for a fixpoint type operator, and polymorphism under the
fixpoint; thus, it fits perfectly fine in System F with iso-recursive
types. So just turn on -XRankNTypes and use them directly:
newtype List a = List { caseList
:: forall r. r -> (a -> List a -> r) -> r }
nil = List (\n c -> n)
cons x xs = List (\n c -> c x xs)
length xs = caseList xs 0 (\x xs' -> 1 + length xs')
--
Live well,
~wren
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