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Demo of emacs/zmq interface using c++. check repo at https://github.com/dennisog/emacs-zmq-hw/
//
// emacs_interface.cc
//
// Lots of this is from http://diobla.info/blog-archive/modules-tut.html
// and from https://github.com/jkitchin/emacs-modules/blob/master/zeromq
//
// Demo of an emacs client to a basic zmq
#include "emacs-zmq-hw.hpp"
#include "connection.hpp"
int plugin_is_GPL_compatible;
//
// non-extern "C" functions. These are not meant to be called by emacs.
//
std::string get_string(emacs_env *env, emacs_value val) {
ptrdiff_t size = 0;
env->copy_string_contents(env, val, NULL, &size);
std::vector<char> buf(size);
env->copy_string_contents(env, val, buf.data(), &size);
std::string str;
str.assign(buf.data(), size);
return str;
}
//
// the 0MQ <-> emacs interface
//
extern "C" {
emacs_value new_connection(emacs_env *env, long nargs, emacs_value args[],
void *data) {
long port = 5555;
std::string ip("127.0.0.1");
auto conn = static_cast<void *>(new myzmq::HWConnection(port, ip));
return env->make_user_ptr(env, myzmq::HWConnection::del, conn);
}
emacs_value delete_connection(emacs_env *env, long nargs, emacs_value args[],
void *data) {
auto conn =
static_cast<myzmq::HWConnection *>(env->get_user_ptr(env, args[0]));
myzmq::HWConnection::del(conn);
return env->intern(env, "t");
}
emacs_value my_zmq_send(emacs_env *env, long nargs, emacs_value args[],
void *data) {
auto conn =
static_cast<myzmq::HWConnection *>(env->get_user_ptr(env, args[0]));
auto str = get_string(env, args[1]);
conn->send(str);
return env->intern(env, "t");
}
emacs_value my_zmq_receive(emacs_env *env, long nargs, emacs_value args[],
void *data) {
auto conn =
static_cast<myzmq::HWConnection *>(env->get_user_ptr(env, args[0]));
auto str = conn->receive();
return env->make_string(env, str.data(), str.length());
}
} // extern "C"
//
// the emacs interface
//
/* Bind NAME to FUN. */
extern "C" {
void bind_function(emacs_env *env, const char *name, emacs_value Sfun) {
/* Set the function cell of the symbol named NAME to SFUN using
the 'fset' function. */
/* Convert the strings to symbols by interning them */
emacs_value Qfset = env->intern(env, "fset");
emacs_value Qsym = env->intern(env, name);
/* Prepare the arguments array */
emacs_value args[] = {Qsym, Sfun};
/* Make the call (2 == nb of arguments) */
env->funcall(env, Qfset, 2, args);
}
/* Provide FEATURE to Emacs. */
void provide(emacs_env *env, const char *feature) {
/* call 'provide' with FEATURE converted to a symbol */
emacs_value Qfeat = env->intern(env, feature);
emacs_value Qprovide = env->intern(env, "provide");
emacs_value args[] = {Qfeat};
env->funcall(env, Qprovide, 1, args);
}
int emacs_module_init(struct emacs_runtime *ert) {
emacs_env *env = ert->get_environment(ert);
// bind the functions
bind_function(env, "zmq-hw-new-connection",
env->make_function(env, 0, 0, new_connection,
"Make a new connection.", NULL));
bind_function(env, "zmq-hw-delete-connection",
env->make_function(env, 1, 1, delete_connection,
"Delete a connection.", NULL));
bind_function(
env, "zmq-hw-send",
env->make_function(env, 2, 2, my_zmq_send, "Send a message.", NULL));
bind_function(
env, "zmq-hw-receive",
env->make_function(env, 1, 1, my_zmq_receive, "Send a message.", NULL));
provide(env, "emacs-zmq-hw");
return 0;
}
} // extern "C"
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