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Re: struct-copy func

From: Ludovic Courtès
Subject: Re: struct-copy func
Date: Tue, 21 Aug 2007 09:49:14 +0200
User-agent: Gnus/5.11 (Gnus v5.11) Emacs/22.1 (gnu/linux)


Kevin Ryde <address@hidden> writes:

> address@hidden (Ludovic Courtès) writes:
>> `struct-copy' must check fields permission
> I didn't want to do that.

I think it has to be done, otherwise that'd just make field permissions

>> `o' fields cannot be copied I think.
> I had in mind just bitwise copying them.  But I guess that slightly
> defeats the purpose of such fields, and could conceivably be a bit evil.

Indeed.  I believe it should be an error to try to copy a struct with
such fields.

> I might rethink it as just a record-copy, since plain records have none
> of those questions.  But that'd need at least `record?' down in C code
> for a type check, so it might have to wait until most of the record
> stuff is in C.

Better leave records as Scheme code IMO.  If you add the above rules to
`struct-copy', then you will be able to
`(define record-copy struct-copy)' and it will actually work because
records have no opaque fields.


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