[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: FFI and disjoint types
From: |
Neil Jerram |
Subject: |
Re: FFI and disjoint types |
Date: |
Mon, 01 Mar 2010 20:49:58 +0000 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/23.1 (gnu/linux) |
address@hidden (Ludovic Courtès) writes:
> Hello,
>
> The nice thing about SMOBs is that they allow disjoint C types to be
> mapped to disjoint Scheme types.
>
> With ‘(system foreign)’, C pointers are mapped to Scheme foreign
> objects, regardless of the type of object pointed to. Thus, to get
> disjoint types in Scheme, foreign objects would need to be boxed in
> structs (since structs are the only way to create disjoint types from
> Scheme).
>
> If this analysis is correct, the resulting code may be somewhat
> inefficient since we end up boxing C pointers twice.
>
> Is this correct? Thoughts?
Sounds reasonable. Perhaps (system foreign) could add a way of
declaring foreign pointer types, and of allowing code to state the type
of a pointer at the time of boxing it.
Neil