It might not be obvious, but not only does ECL enable the embedding of C code in Lisp code, it supports C++ as well. The following works, for instance (assuming your ECL was compiled --with-cxx):
(in-package #:cl-user)
(ffi:clines "#include <sstream>")
(ffi:clines "#include <iostream>")
(ffi:clines "#include <cstring>")
(ffi:clines "#include <gc/gc_cpp.h>")
(defun c++hex (x)
(ffi:c-inline (x) (:int) :cstring "{
std::ostringstream out;
out << std::hex << #0;
@(return) = new (GC) char[out.str().size() + 1];
strcpy(@(return), out.str().c_str());
}")))
Then, at the REPL:
CL-USER> (c++hex 123456) "1e240"
I think that's pretty nifty.
Comments
Matthias, thanks for this great post. Two comments: Extra paren in the defun of c++hex; stops it compiling. Secondly, what's implied here is that it is possible to evaluate the defun for c++hex and then run it at the REPL. That won't work "as-is." It requires the intermediate step of compilation via e.g. (compile-file) and a subsequent load operation of the fas file.
http://chriskohlhepp.wordpress.com/embedding-lisp-in-cplusplus-a-recipe/
Viele Gruesse
Chris Kohlhepp
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