savvy-bindgen

Parse Rust functions, and generate C and R code.

For the full details, please read savvy's crate documentation.

``` rust /// Convert to Upper-case /// /// @param x A character vector. /// @export

[savvy]

fn to_upper(x: StringSxp) -> savvy::Result { // Use Owned{type}Sxp to allocate an R vector for output. let mut out = OwnedStringSxp::new(x.len())?;

for (i, e) in x.iter().enumerate() {
    // To Rust, missing value is an ordinary value. In `&str`'s case, it's just "NA".
    // You have to use `.is_na()` method to distinguish the missing value.
    if e.is_na() {
        // Values need to be set by `set_elt()` one by one.
        out.set_elt(i, <&str>::na())?;
        continue;
    }

    let e_upper = e.to_uppercase();
    out.set_elt(i, e_upper.as_str())?;
}

// `Owned{type}Sxp` type implements `From` trait for `SEXP`, so you can use `into()`.
Ok(out.into())

} ```