impl-enum 0.1.0

Macro for generating methods on an enum that match on the enum and call the same method on each variant.
Documentation 
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//! The variant of the writer is dynamically selected with an environment variable.
//! Using the macro, we get the convenience of a trait object with the performance of an enum.

use std::env;
use std::fs::File;
use std::io::Cursor;
use std::io::Write;

#[impl_enum::with_methods {
    fn write_all(&mut self, buf: &[u8]) -> Result<(), std::io::Error> {}
    pub fn write(&mut self, buf: &[u8]) -> Result<usize, std::io::Error> {}
}]
enum Writer {
    Cursor(Cursor<Vec<u8>>),
    File(File),
}

fn get_writer() -> Writer {
    if let Ok(path) = env::var("WRITER_FILE") {
        Writer::File(File::create(path).unwrap())
    } else {
        Writer::Cursor(Cursor::new(vec![]))
    }
}

fn main() {
    let mut writer = get_writer();
    writer.write_all(b"hello!").unwrap();
}