/
lib.rs
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/
lib.rs
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extern crate proc_macro;
use proc_macro::{TokenStream};
use syn::punctuated::Punctuated;
use syn::{parse_macro_input, parse_quote, Expr, FnArg, Item, ItemFn, ItemImpl, Ident, parse::ParseStream};
use quote::{format_ident, quote};
use syn::Token;
mod output_r;
const INIT_PREFIX: &str = "init__";
const WRAP_PREFIX: &str = "wrap__";
#[derive(Debug)]
struct ExtendrOptions {
}
// Generate a list of arguments for the wrapper. All arguments are SEXP for .Call in R.
fn translate_formal(input: &FnArg, self_ty: Option<&syn::Type>) -> FnArg {
match input {
// function argument.
FnArg::Typed(ref pattype) => {
let pat = &pattype.pat.as_ref();
return parse_quote! { #pat : extendr_api::SEXP };
}
// &self
FnArg::Receiver(ref reciever) => {
if !reciever.attrs.is_empty() || reciever.reference.is_none() {
panic!("expected &self or &mut self");
}
if self_ty.is_none() {
panic!("found &self in non-impl function - have you missed the #[extendr] before the impl?");
}
return parse_quote! { _self : extendr_api::SEXP };
}
}
}
// Convert SEXP arguments into Robj. This maintains the lifetime of references.
fn translate_to_robj(input: &FnArg) -> syn::Stmt {
match input {
FnArg::Typed(ref pattype) => {
let pat = &pattype.pat.as_ref();
if let syn::Pat::Ident(ref ident) = pat {
let varname = format_ident!("_{}_robj", ident.ident);
parse_quote! { let #varname = extendr_api::new_borrowed(#pat); }
} else {
panic!("expect identifier as arg name")
}
}
FnArg::Receiver(_) => {
parse_quote! { let mut _self_robj = extendr_api::new_borrowed(_self); }
}
}
}
// Generate actual argument list for the call (ie. a list of conversions).
fn translate_actual(input: &FnArg) -> Option<Expr> {
match input {
FnArg::Typed(ref pattype) => {
let pat = &pattype.pat.as_ref();
let ty = &pattype.ty.as_ref();
if let syn::Pat::Ident(ref ident) = pat {
let varname = format_ident!("_{}_robj", ident.ident);
Some(parse_quote!{ extendr_api::unwrap_or_throw(<#ty>::from_robj(&#varname)) })
} else {
None
}
}
FnArg::Receiver(_) => {
// Do not use self explicitly as an actual arg.
None
}
}
}
/// Parse a set of attribute arguments for #[extendr(opts...)]
fn parse_options(_opts: &mut ExtendrOptions, _arg: &syn::NestedMeta) {
/*use syn::{Lit, Meta, MetaNameValue, NestedMeta};
match arg {
NestedMeta::Meta(Meta::NameValue(MetaNameValue {
ref path,
eq_token: _,
lit: Lit::Str(ref _lit_str),
})) => {
}
_ => panic!("expected #[extendr(opt = \"string\", ...)]"),
}*/
}
/// Generate bindings for a single function.
fn extendr_function(args: Vec<syn::NestedMeta>, func: ItemFn) -> TokenStream {
let mut opts = ExtendrOptions {};
for arg in &args {
parse_options(&mut opts, arg);
}
let mut wrappers = Vec::new();
generate_wrappers(&opts, &mut wrappers, "", &func.sig, None);
TokenStream::from(quote!{
#func
# ( #wrappers )*
})
}
// Generate wrappers for a specific function.
fn generate_wrappers(_opts: &ExtendrOptions, wrappers: &mut Vec<ItemFn>, prefix: &str, sig: &syn::Signature, self_ty: Option<&syn::Type>) {
let func_name = &sig.ident;
let raw_wrap_name = format!("{}{}{}", WRAP_PREFIX, prefix, func_name);
let wrap_name = format_ident!("{}{}{}", WRAP_PREFIX, prefix, func_name);
let init_name = format_ident!("{}{}{}", INIT_PREFIX, prefix, func_name);
let wrap_name_str = format!("{}", wrap_name);
let inputs = &sig.inputs;
let has_self = match inputs.iter().next() {
Some(FnArg::Receiver(_)) => true,
_ => false
};
let call_name = if has_self {
let is_mut = match inputs.iter().next() {
Some(FnArg::Receiver(ref reciever)) => reciever.mutability.is_some(),
_ => false
};
if is_mut {
// eg. Person::name(&mut self)
quote! { extendr_api::unwrap_or_throw(
<&mut #self_ty>::from_robj(&_self_robj)
).#func_name }
} else {
// eg. Person::name(&self)
quote! { extendr_api::unwrap_or_throw(
<&#self_ty>::from_robj(&_self_robj)
).#func_name }
}
} else if let Some(ref self_ty) = &self_ty {
// eg. Person::new()
quote! { <#self_ty>::#func_name }
} else {
// eg. aux_func()
quote! { #func_name }
};
let formal_args: Punctuated<FnArg, Token![,]> = inputs
.iter()
.map(|input| translate_formal(input, self_ty))
.collect();
let convert_args: Vec<syn::Stmt> = inputs
.iter()
.map(|input| translate_to_robj(input))
.collect();
let actual_args: Punctuated<Expr, Token![,]> = inputs
.iter()
.filter_map(|input| translate_actual(input))
.collect();
// let R_formal_args: Vec<String> = inputs
// .iter()
// .filter_map(|input| translate_R_formal(input))
// .collect();
let num_args = inputs.len() as i32;
output_r::output_r_wrapper(
func_name,
&raw_wrap_name,
sig.inputs.clone().into_iter().collect(),
&sig.output,
);
wrappers.push(parse_quote!(
#[no_mangle]
#[allow(non_snake_case)]
pub extern "C" fn #wrap_name(#formal_args) -> extendr_api::SEXP {
unsafe {
use extendr_api::FromRobj;
#( #convert_args )*
extendr_api::Robj::from(#call_name(#actual_args)).get()
}
}
));
wrappers.push(parse_quote!(
#[allow(non_snake_case)]
fn #init_name(info: *mut extendr_api::DllInfo, call_methods: &mut Vec<extendr_api::CallMethod>) {
call_methods.push(
extendr_api::CallMethod {
call_symbol: std::ffi::CString::new(#wrap_name_str).unwrap(),
func_ptr: #wrap_name as * const u8,
num_args: #num_args,
}
)
}
));
}
/// Handle trait implementations.
fn extendr_impl(mut item_impl: ItemImpl) -> TokenStream {
let opts = ExtendrOptions {};
let self_ty = item_impl.self_ty.as_ref();
let self_ty_name = quote! {#self_ty}.to_string();
let prefix = format!("{}__", self_ty_name);
let mut method_init_names = Vec::new();
let mut wrappers = Vec::new();
for impl_item in &mut item_impl.items {
if let syn::ImplItem::Method(ref mut method) = impl_item {
method_init_names.push(format_ident!("{}{}__{}", INIT_PREFIX, self_ty_name, method.sig.ident));
generate_wrappers(&opts, &mut wrappers, prefix.as_str(), &method.sig, Some(self_ty));
}
}
let init_name = format_ident!("{}{}", INIT_PREFIX, self_ty_name);
let finalizer_name = format_ident!("__finalize__{}", self_ty_name);
let expanded = TokenStream::from(quote! {
#item_impl
#( #wrappers )*
impl<'a> extendr_api::FromRobj<'a> for &#self_ty {
fn from_robj(robj: &'a Robj) -> Result<Self, &'static str> {
if robj.check_external_ptr(#self_ty_name) {
Ok(unsafe { std::mem::transmute(robj.externalPtrAddr::<#self_ty>()) })
} else {
Err(concat!("expected ", #self_ty_name))
}
}
}
impl<'a> extendr_api::FromRobj<'a> for &mut #self_ty {
fn from_robj(robj: &'a Robj) -> Result<Self, &'static str> {
if robj.check_external_ptr(#self_ty_name) {
Ok(unsafe { std::mem::transmute(robj.externalPtrAddr::<#self_ty>()) })
} else {
Err(concat!("expected ", #self_ty_name))
}
}
}
impl From<#self_ty> for Robj {
fn from(value: #self_ty) -> Self {
unsafe {
let ptr = Box::into_raw(Box::new(value));
let res = Robj::makeExternalPtr(ptr, Robj::from(#self_ty_name), Robj::from(()));
res.registerCFinalizer(Some(#finalizer_name));
res
}
}
}
extern "C" fn #finalizer_name (sexp: extendr_api::SEXP) {
unsafe {
let robj = extendr_api::new_borrowed(sexp);
if robj.check_external_ptr(#self_ty_name) {
//eprintln!("finalize {}", #self_ty_name);
let ptr = robj.externalPtrAddr::<#self_ty>();
Box::from_raw(ptr);
}
}
}
#[allow(non_snake_case)]
fn #init_name(info: *mut extendr_api::DllInfo, call_methods: &mut Vec<extendr_api::CallMethod>) {
#( #method_init_names(info, call_methods); )*
}
});
//eprintln!("{}", expanded);
expanded
}
/// Generate bindings for a single function.
#[proc_macro_attribute]
pub fn extendr(attr: TokenStream, item: TokenStream) -> TokenStream {
let args = parse_macro_input!(attr as syn::AttributeArgs);
match parse_macro_input!(item as Item) {
Item::Fn(func) => return extendr_function(args, func),
Item::Impl(item_impl) => return extendr_impl(item_impl),
other_item => {
TokenStream::from(quote! {#other_item})
}
}
}
#[derive(Debug)]
struct Module {
modname: Option<Ident>,
fnnames: Vec<Ident>,
implnames: Vec<Ident>,
}
impl syn::parse::Parse for Module {
fn parse(input: ParseStream) -> syn::Result<Self> {
use syn::spanned::Spanned;
let mut res = Self {
modname: None,
fnnames: Vec::new(),
implnames: Vec::new(),
};
while !input.is_empty() {
if let Ok(kmod) = input.parse::<Token![mod]>() {
let name : Ident = input.parse()?;
if !res.modname.is_none() {
return Err(syn::Error::new(kmod.span(), "only one mod allowed"));
}
res.modname = Some(name);
} else if let Ok(_) = input.parse::<Token![fn]>() {
res.fnnames.push(input.parse()?);
} else if let Ok(_) = input.parse::<Token![impl]>() {
res.implnames.push(input.parse()?);
} else {
return Err(syn::Error::new(input.span(), "expected mod, fn or impl"));
}
input.parse::<Token![;]>()?;
}
if res.modname.is_none() {
return Err(syn::Error::new(input.span(), "expected one 'mod name'"));
}
Ok(res)
}
}
/// Define a module and export symbols to R
/// Example:
///
/// extendr_module! {
/// mod name;
/// fn my_func1;
/// fn my_func2;
/// impl MyTrait;
/// }
///
#[proc_macro]
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_lib{}", modname);
let fninitnames = fnnames.iter().map(|id| format_ident!("{}{}", INIT_PREFIX, id));
let implinitnames = implnames.iter().map(|id| format_ident!("{}{}", INIT_PREFIX, id));
TokenStream::from(quote!{
#[no_mangle]
#[allow(non_snake_case)]
pub extern "C" fn #module_init_name(info: * mut extendr_api::DllInfo) {
let mut call_methods = Vec::new();
#( #fninitnames(info, &mut call_methods); )*
#( #implinitnames(info, &mut call_methods); )*
unsafe { extendr_api::register_call_methods(info, call_methods.as_ref()) };
}
})
}