Fix module registration. (#93)

* set up registration forwarding

* forward routine registraton from C to Rust

* avoid reading Rinternals.h.

* fix up examples (somewhat)

extendr-api/examples/R/data/src/entrypoint.c

@@ -1,11 +1,9 @@
+// We need to forward routine registration from C to Rust 
+// to avoid the linker removing the static library.
 
+void R_init_data_extendr(void *dll);
 
-// Take the address of the wrap__hello stub function to avoid
-// the linker removing the static library.
-//
-// This will be removed in future versions with the module macro.
-void R_init_libdata();
-
-void *__dummy = (void*)&R_init_libdata;
-
+void R_init_data(void *dll) {
+  R_init_data_extendr(dll);
+}
 

extendr-api/examples/R/hello/README.md

@@ -8,6 +8,5 @@ Then in R:
 
     > library(hello)
     > hello()
-    hello
-    NULL
+    [1] "hello"
     > 

extendr-api/examples/R/hello/src/entrypoint.c

@@ -1,11 +1,9 @@
+// We need to forward routine registration from C to Rust 
+// to avoid the linker removing the static library.
 
+void R_init_hello_extendr(void *dll);
 
-// Take the address of the wrap__hello stub function to avoid
-// the linker removing the static library.
-//
-// This will be removed in future versions with the module macro.
-void R_init_libhello();
-
-void *__dummy = (void*)&R_init_libhello;
-
+void R_init_hello(void *dll) {
+  R_init_hello_extendr(dll);
+}
 

extendr-macros/src/lib.rs

@@ -17,12 +17,15 @@
 // `cargo expand` extension.
 //
 // Invoking the #[extendr_module] macro generates an entrypoint for the
-// library that will be called by R.
+// library that will be called by R. Note that we add a postfix
+// `_extendr` to the init function because we need to forward routine
+// registration from C to Rust, and the C function will be called
+// `R_init_hello()`.
 //
 // ```ignore
 // #[no_mangle]
 // #[allow(non_snake_case)]
-// pub extern "C" fn R_init_hello(info: *mut extendr_api::DllInfo) {
+// pub extern "C" fn R_init_hello_extendr(info: *mut extendr_api::DllInfo) {
 //     let mut call_methods = Vec::new();
 //     init__hello(info, &mut call_methods);
 //     unsafe { extendr_api::register_call_methods(info, call_methods.as_ref()) };
@@ -485,7 +488,7 @@ impl syn::parse::Parse for Module {
 /// ```ignore
 /// #[no_mangle]
 /// #[allow(non_snake_case)]
-/// pub extern "C" fn R_init_hello(info: *mut extendr_api::DllInfo) {
+/// pub extern "C" fn R_init_hello_extendr(info: *mut extendr_api::DllInfo) {
 ///     let mut call_methods = Vec::new();
 ///     init__hello(info, &mut call_methods);
 ///     unsafe { extendr_api::register_call_methods(info, call_methods.as_ref()) };
@@ -496,7 +499,7 @@ pub fn extendr_module(item: TokenStream) -> TokenStream {
     let module = parse_macro_input!(item as Module);
     let Module {modname, fnnames, implnames} = module;
     let modname = modname.unwrap();
-    let module_init_name = format_ident!("R_init_{}", modname);
+    let module_init_name = format_ident!("R_init_{}_extendr", modname);
 
     let fninitnames = fnnames.iter().map(|id| format_ident!("{}{}", INIT_PREFIX, id));
     let implinitnames = implnames.iter().map(|id| format_ident!("{}{}", INIT_PREFIX, id));

tests/extendrtests/src/entrypoint.c

@@ -1,29 +1,8 @@
-/*
-// Take the address of the wrap__hello stub function to avoid
-// the linker removing the static library.
-//
-// This will be removed in future versions with the module macro.
-void wrap__hello();
+// We need to forward routine registration from C to Rust 
+// to avoid the linker removing the static library.
 
-void *x = (void*)&wrap__hello;
-*/
+void R_init_extendrtests_extendr(void *dll);
 
-
-#define R_NO_REMAP
-#define STRICT_R_HEADERS
-#include <Rinternals.h>
-
-SEXP wrap__hello();
-SEXP wrap__add_ints();
-
-// Standard R package stuff
-static const R_CallMethodDef CallEntries[] = {
-  {"wrap__hello", (DL_FUNC) &wrap__hello, 0},
-  {"wrap__add_ints", (DL_FUNC) &wrap__add_ints, 2},
-  {NULL, NULL, 0}
-};
-
-void R_init_extendrtests(DllInfo *dll) {
-  R_registerRoutines(dll, NULL, CallEntries, NULL, NULL);
-  R_useDynamicSymbols(dll, FALSE);
+void R_init_extendrtests(void *dll) {
+  R_init_extendrtests_extendr(dll);
 }

tests/extendrtests/src/rust/Cargo.toml

@@ -16,7 +16,7 @@ crate-type = ["staticlib"]
 extendr-api = "*"
 
 [patch.crates-io]
-extendr-api = { git = "https://github.com/extendr/extendr" }
-extendr-engine = { git = "https://github.com/extendr/extendr" }
-extendr-macros = { git = "https://github.com/extendr/extendr" }
+extendr-api = { git = "https://github.com/clauswilke/extendr", branch = "reg-forwarding" }
+extendr-engine = { git = "https://github.com/clauswilke/extendr", branch = "reg-forwarding" }
+extendr-macros = { git = "https://github.com/clauswilke/extendr", branch = "reg-forwarding" }
 #libR-sys = { git = "https://github.com/extendr/libR-sys" }

tests/extendrtests/src/rust/src/lib.rs

@@ -11,10 +11,9 @@ fn add_ints(x:i32, y:i32) -> i32 {
 }
 
 
-/* Doesn't currently work yet.
 // Macro to generate exports
 extendr_module! {
     mod extendrtests;
     fn hello;
+    fn add_ints;
 }
-*/