[Chicken-hackers] [PATCH] Fix record type tags to be nonglobal by module-prefixing them

[Peter Bex]

Hi all,

A long time ago, we had a patch that tried to prefix the current module
name onto a record type's tag (727b2b3fea271474540f215af4842d32e82e7e6d).
This was reverted later on because it turned out to be somewhat
incompatible with various things, like the record-variants egg.

I think this is quite an important change which we should try to get
in for CHICKEN 5 again, because it's a change that changes fundamentally
how record types are tagged.  I believe record-variants can be fixed
if we also fix #1342 by defining the "type name" which you pass to
define-record-type as an identifier.

So (define-record foo a) defines foo?, make-foo, foo-a, foo-a-set!, but
also just foo.  This is apparently a requirement of SRFI-99 and R7RS
anyway, and it should also help us to access the tag in record-variants.

The attached patch is a fairly straightforward re-application of 727b2b3,
with a slightly ore extensive test suite.  It also adds the definition
of the identifier like I mentioned before.

I'd add a patch for record-variants, but I see we have no port to
CHICKEN 5 for it yet.  In any case, instead of quoting the type name,
it would simply be used unquoted, as that's the identifier which holds
the tag.  I don't know exactly what the problem with coops was, but I
presume it was either caused by record-variants not working or we can
fix it in a similar way by using the record identifier instead of the
quoted tag.

There are two remaining questions:
- Should the core record types like "promise", "thread" and so on be
   tagged with a module prefix?  I think it's fine to keep them the
   way they are.
- Should the identifier be bound to the raw tag, or should it be wrapped
   in some kind of opaque object (perhaps a "record type" record type)?
   Personally, I think it's probably better (and also less confusing to
   the user) to wrap it, but that's a slightly larger change which can
   go in later, so I decided to keep this patch simple.

Cheers,
Peter

0001-Get-rid-of-global-namespace-for-record-types.patch
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