1 files changed, 53 insertions, 0 deletions
diff --git a/src/repl.rs b/src/repl.rs
new file mode 100644
index 0000000..c44174a
--- /dev/null
+++ b/src/repl.rs
@@ -0,0 +1,53 @@
+use futures::future::Future;
+use std::io::Write;
+
+#[derive(Debug)]
+enum Error {
+    ReadError(crate::readline::Error),
+    // EvalError(std::io::Error),
+    PrintError(std::io::Error),
+    // LoopError,
+}
+
+pub fn repl() {
+    tokio::run(tokio::prelude::future::lazy(|| {
+        let mut done = false;
+        while !done {
+            let res = read()
+                .and_then(move |line| eval(&line))
+                .and_then(move |out| print(&out))
+                .wait();
+            match res {
+                Ok(_) => {}
+                Err(Error::ReadError(crate::readline::Error::EOF)) => {
+                    done = true;
+                }
+                Err(e) => {
+                    let stderr = std::io::stderr();
+                    let mut stderr = stderr.lock();
+                    write!(stderr, "error: {:?}", e).unwrap();
+                    stderr.flush().unwrap();
+                    done = true;
+                }
+            }
+        }
+        futures::future::ok(())
+    }));
+}
+
+fn read() -> impl futures::future::Future<Item = String, Error = Error> {
+    crate::readline::readline("$ ", true).map_err(|e| Error::ReadError(e))
+}
+
+fn eval(line: &str) -> Result<String, Error> {
+    Ok(format!("got line '{}'\r\n", line))
+}
+
+fn print(out: &str) -> Result<(), Error> {
+    let stdout = std::io::stdout();
+    let mut stdout = stdout.lock();
+    stdout
+        .write(out.as_bytes())
+        .map_err(|e| Error::PrintError(e))?;
+    stdout.flush().map_err(|e| Error::PrintError(e))
+}