Ross Paterson:
On Wed, Jul 08, 2009 at 03:09:29PM +0100, Simon Marlow wrote:
1. Just drop the whole libraries section from the report. The
Report will still define the Prelude, however.
There will be some loose ends where the rest of the report
refers to entities from these libraries, e.g. the Prelude
refers to Rational from the Ratio library. We just have to
fix up these references, moving the appropriate definitions
into the Report as necessary.
Some of the loose ends:
The defaulting rules (section 4.3.4) apply to any class "defined in
the
Prelude or a standard library". The non-Prelude classes involved are
Ix and Random.
The FFI spec refers to types Int8, Int16, Int32, Int64, Word8, Word16,
Word32, Word64, Ptr a, FunPtr a and StablePtr a. Perhaps they
should move
to the Prelude when the non-library part of the FFI spec is
incorporated
into the Report?
If we have these types in the Prelude, the associated functions should
be in the Prelude, too, and I'd be reluctant to include operations
that are not memory-safe in the Prelude. So, I think, we need at
least a standard library for the FFI. (In the FFI spec, we after all
went to a lot of trouble to realise as much as possible of the needed
functionality as libraries, to change the core language as little as
possible.)
I understand the desire to cut down on the number of library functions
defined in the report, but ultimately, the language needs to provide a
basic set of functionality that is the basis for implementing all the
other libraries. Otherwise, the usefulness of the standard gets
undermined.
Apart from the Prelude, I think we should ask the following question
to decide whether we can omit some library functionality from the
language definition:
If we omit the functionality under consideration,
can we implement it in a portable manner with what remains in the
definition?
If that is not the case, we ought to include it.
Manuel
PS: As a historical anecdote, it was a major shortcoming of Modula-2
over C that Modula-2 didn't define it's basic libraries properly with
the language (whereas C did).
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