Second draft of the Haskell 2010 report available

Yitzchak Gale gale at
Tue Jul 6 10:12:24 EDT 2010

1.2: "it is essentially a slightly sugared variant of the lambda calculus"
Should it be the simply-typed lambda calculus?
Also, there should be a reference; a significant percentage of those
reading this report will have never heard of the lambda calculus.

"with a straightforward denotational semantics"
Seems that it should be so. Has anyone actually ever done that?
If so, reference. If not, qualify.

1.3: "Errors in Haskell are semantically equivalent to _|_. Technically,
they are not distinguishable from nontermination, so the language
includes no mechanism for detecting or acting upon errors.
However, implementations will probably try to provide useful
information about errors. See Section 3.1 [where error and undefined
are described]."

This paragraph has always been very unsatisfying, especially since
the Report itself does in fact provide a way of catching some errors
at least since Haskell 98.

41.1: "The fail method of the IO instance of the Monad class raises
a userError"
Should be the default fail method.


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