Compilation of "hello" example fails when using extendr from crates.io

[extendr]

Compilation of "hello" example fails when using extendr from crates.io

[clauswilke]

I've figured out what the problem is. The code of extendr_macros on crates.io doesn't match the code in the git repo. To show this, I've copied the entire lib.rs file from crates.io below, in the details. You can see that it defines a macro export_function but no macro extendr. I also note that the version of extendr_macros on crates.io (and in the github repo) is listed as 0.1.2, when the version of extendr_api is 0.1.3. Maybe all that is needed to fix this is to update the version of extendr_macros and re-publish on crates.io?

extern crate proc_macro;
use proc_macro::TokenStream;
use syn::{parse_macro_input, parse_quote, ItemFn, FnArg, Expr};
use syn::punctuated::Punctuated;
//use syn::parse::Parse;
use syn::Token;
use quote::{quote, format_ident};

//type CompileError = Box<dyn std::error::Error>;

// All arguments are SEXP for .Call in R.
fn translate_formal(input : &FnArg) -> FnArg {
    match input {
        FnArg::Typed(ref pattype) => {
            let pat = &pattype.pat.as_ref();
            return parse_quote!{ #pat : extendr_api::SEXP };
        },
        _ => ()
    }
    panic!("Exported function argument must be a primitive or Robj.");
}

// Convert SEXP arguments into native types if we can.
fn translate_actual(input : &FnArg) -> Expr {
    match input {
        FnArg::Typed(ref pattype) => {
            let pat = &pattype.pat.as_ref();
            let ty = &pattype.ty.as_ref();
            return parse_quote!{ extendr_api::unwrap_or_throw(from_robj::<#ty>(&new_borrowed(#pat))) };
        },
        _ => ()
    }
    panic!("Exported function argument must be a primitive or Robj.");
}

#[proc_macro_attribute]
/// Generate bindings for a single function.
pub fn export_function(_attr: TokenStream, item: TokenStream) -> TokenStream {
    let func = parse_macro_input!(item as ItemFn);
    let func_name = &func.sig.ident;
    let wrap_name = format_ident!("__wrap__{}", func_name);

    let formal_args : Punctuated<FnArg, Token![,]> = func.sig.inputs.iter()
        .map(|input| {
            translate_formal(input)
        }).collect();

    let actual_args : Punctuated<Expr, Token![,]> = func.sig.inputs.iter()
        .map(|input| {
            translate_actual(input)
        }).collect();

        //println!("export_function func: {:#?}", func);

    let expanded = quote! {
        // #[allow(dead_code)]
        #func

        #[no_mangle]
        pub extern "C" fn #wrap_name(#formal_args) -> extendr_api::SEXP {
            use extendr_api::{from_robj, new_borrowed};
            unsafe {
                extendr_api::Robj::from(#func_name(#actual_args)).get()
            }
        }
    };
    
    //println!("res: {}", expanded);
    TokenStream::from(expanded)
}

[clauswilke]

Thinking about the right order of doing things, so we end up with fully functioning crates on crates.io: Maybe first merge the libR-sys PR (extendr/libR-sys#7), which will increase the version of libR-sys. Then publish that on crates.io. Then increase the version dependency in extendr, and then increase extendr-{api, macros} versions to 0.1.4.

[andy-thomason]

Thanks for your hard work, @clauswilke and others.

[andy-thomason]

I've updated some of the documentation and switched the docs to docs.rs.

Please let me know if this work for everyone.

A CI test on Appveyor or Azure would be a useful thing to keep this working.

[clauswilke]

Sounds good to me.

[clauswilke]

Just to be sure it doesn't fall through the cracks: extendr-macros needs a version bump also, here:

extendr/extendr-macros/Cargo.toml

Line 3 in 8114138

version = "0.1.2"

and here:

extendr/extendr-api/Cargo.toml

Line 13 in 8114138

extendr-macros = { path = "../extendr-macros", version="0.1.2" }

[andy-thomason]

I've created a PR for this and will publish the crate.

[clauswilke]

I believe this is fixed now.