downs wrote:
I've just committed a module to tools (tools.cpp,
http://dsource.org/projects/scrapple/Trunk/tools/tools/cpp.d ) that should
enable linking and using any C++ library with D programs without creating a C
wrapper for it.
The code has been tested with a simple multiple-inheritance sample:
http://paste.dprogramming.com/dpv8hpjp
The D code to bind to this is http://paste.dprogramming.com/dphlv1ot . It
requires a symlink to the tools folder in its directory.
Caveats:
- D1
- Only works on g++4's "newapi" layout and mangling (but should be reasonably
portable).
At http://www.agner.org/optimize/, you can find a document
(calling_conventions.pdf) which gives full details of the C++ name
mangling schemes for various compilers.
Writing this also gave us what I believe to be a fair contender to Most
Horrifying Statement of D Ever Written:
fndefs ~= `mixin("extern(C) `~t~` "~`~mname~`~"`~fnparams~`; ");`~'\n'~
`mixin("`~fn~`("~refToParamList("Params!(typeof(&"~`~mname~`~"))",
isRef!(typeof(mixin("&"~`~mname~`))))~") {
return
"~`~mname~`~"("~refToValueList(isRef!(typeof(mixin("&"~`~mname~`))))~");
}
"); `;
Ugh, that's unreadable.
I found that with a little function called string enquote(string s),
which changes s into "s", this kind of stuff looks much less terrible.
In particular you get rid of the nasty mix of ` and ".
fndefs ~= "mixin(" ~ enquote("extern(C)" ~ t ~ " ")
~ "~" ~ mname
~ "~" ~ enquote(fnparams ~ ";")
~ ");"
~ "mixin(" ~ ....
// etc
