Merge pull request #19 from CarolineMorton/add-r

Add r

bindings/r/.cargo/config.toml

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+[build]
+rustflags = ["-C", "link-args=-undefined dynamic_lookup"]

bindings/r/Cargo.toml

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+[package]
+name = "codelist"
+version = "0.1.0"
+edition = "2021"
+
+[lib]
+crate-type = ["staticlib"]
+name = "codelist"
+path = "src/lib.rs"
+# Build as a dynamic library
+
+[dependencies]
+extendr-api = "0.7.1"

bindings/r/DESCRIPTION

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+Package: codelist
+Title: R Wrapper for Rust Functions
+Version: 0.1.0
+Authors@R:
+    person("Your Name", "Your Last Name", email = "[email protected]", role = c("aut", "cre"))
+Description: Provides R bindings for Rust functions using extendr.
+License: MIT + file LICENSE
+Encoding: UTF-8
+Roxygen: list(markdown = TRUE)
+RoxygenNote: 7.3.2
+Imports:
+    rextendr
+Config/rextendr/version: 0.3.1

bindings/r/NAMESPACE

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+useDynLib(codelist, .registration = TRUE)
+export(hello)

bindings/r/R/extendr-wrappers.R

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+# Generated by extendr: Do not edit by hand
+
+# nolint start
+
+#
+# This file was created with the following call:
+#   .Call("wrap__make_codelist_wrappers", use_symbols = TRUE, package_name = "codelist")
+
+#' @usage NULL
+#' @useDynLib codelist, .registration = TRUE
+NULL
+
+hello <- function() .Call(wrap__hello)
+
+
+# nolint end

bindings/r/README.md

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+# R Bindings
+
+This package demonstrates how to call Rust functions from R using extendr.
+I (@CarolineMorton) have not yet implemented this with our Codelist library 
+but rather with a simple "hello world" function.
+
+## Prerequisites
+
+- Install R (version 4.0 or higher recommended)
+    - macOS: `brew install r`
+
+#### Notes
+- My R installation took a long time to complete, so be patient here. It seems like it was broken 
+because for some reason installing R also means it installs the latest version of Python, Pytorch and
+a bunch of other things. I'm not super familiar with R or why it does this but 🤷‍♀️ it might just be a
+me problem.
+- I think you need to have Xcode installed on macOS to get the C bridge to work.
+- I had to add R to my path before I could get into the R console via the terminal:
+```bash
+R
+```
+- An alternative is to use RStudio, which is a popular IDE for R.
+- You can exit the R console with `q()`. You then get this:
+```bash
+Save workspace image? [y/n/c]: 
+```
+which i said no to.
+
+## Building and Installing
+
+1. First build the Rust library:
+```bash
+cd r
+cargo build --release
+```
+
+This will create a shared library in `target/release/libcodelist.dylib` (macOS) or `target/release/libcodelist.so` (Linux).
+
+2. Open R with the terminal command `R`
+and install required packages. If you get an error message when running this, you may also need to install package dependencies for `devtools` first if not already installed:
+```r
+install.packages("devtools") 
+install.packages("rextendr")
+```
+
+I picked `64` as the mirror I wanted to use. 
+
+
+3. Build and load the package:
+```r
+rextendr::document()
+devtools::document()
+devtools::load_all()
+```
+
+4. Test that it works:
+```r
+hello()
+```
+
+## Installing Permanently
+
+To install the package permanently:
+
+```r
+devtools::build()
+devtools::install()
+```
+
+After installation, you can use it like any other R package:
+
+```r
+library(codelist)
+hello()
+```

bindings/r/src/Makevars

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+LIBDIR = ../target/release
+STATLIB = $(LIBDIR)/libcodelist.a
+PKG_LIBS = -L$(LIBDIR) -lcodelist
+
+all: C_clean
+
+$(SHLIB): $(STATLIB)
+
+$(STATLIB):
+	cargo build --lib --release
+
+C_clean:
+	rm -Rf $(SHLIB) $(STATLIB) $(OBJECTS)

bindings/r/src/entrypoint.c

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+// We need to forward routine registration from C to Rust
+// to avoid the linker removing the static library.
+
+void R_init_codelist_extendr(void *dll);
+
+void R_init_codelist(void *dll) {
+    R_init_codelist_extendr(dll);
+}

bindings/r/src/lib.rs

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+use extendr_api::prelude::*;
+
+#[extendr]
+fn hello() -> &'static str {
+    println!("hello function called");
+    "hello"
+}
+
+extendr_module! {
+    mod codelist;
+    fn hello;
+}