Refactor loop and fix prompt

src/cli.rs

@@ -6,12 +6,18 @@ use clap::{Parser};
 pub struct CliArgs {
     /// Script to run
     pub file: Option<String>,
+
     /// Generate m3u8 playlist
     #[clap(short, long)]
     pub playlist: Option<String>,
-    /// In REPL mode, wait for all music in the queue to complete
-    #[clap(short, long)]
+
+    /// In REPL mode, wait for all music in the queue to complete before accepting new input
+    #[clap(long)]
     pub wait: bool,
+
+    /// In REPL mode, the prompt to display
+    #[clap(long, default_value_t = String::from("|"))]
+    pub prompt: String
 }
 
 pub fn parse() -> CliArgs {

src/repl.rs

@@ -1,27 +1,39 @@
 //! Read, Execute, Print Loop functionality
 
-use std::io::{self, Write, Read};
+use std::io::{self, Write, Read, Stdin};
 
 use mps_interpreter::MpsRunner;
 use mps_player::{MpsPlayer, MpsController};
 
 use super::cli::CliArgs;
-use super::channel_io::channel_io;
+use super::channel_io::{channel_io, ChannelWriter};
+
+struct ReplState {
+    stdin: Stdin,
+    line_number: usize,
+    statement_buf: Vec<u8>,
+    writer: ChannelWriter,
+}
+
+impl ReplState {
+    fn new(chan_writer: ChannelWriter) -> Self {
+        Self {
+            stdin: io::stdin(),
+            line_number: 0,
+            statement_buf: Vec::new(),
+            writer: chan_writer,
+        }
+    }
+}
 
 pub fn repl(args: CliArgs) {
-    let (mut writer, reader) = channel_io();
+    let (writer, reader) = channel_io();
     let player_builder = move || {
         let runner = MpsRunner::with_stream(reader);
         let player = MpsPlayer::new(runner).unwrap();
         player
     };
-    let stdin_t = io::stdin();
-    let mut stdin = stdin_t.lock();
-    let mut buf: Vec<u8> = Vec::new();
-    let mut read_buf = [0];
-    let mut current_line = 0;
-    // TODO: enable raw mode (char by char) reading of stdin
-    // TODO: generalize loop for better code reuse between playlist and playback mode
+    let mut state = ReplState::new(writer);
     if let Some(playlist_file) = &args.playlist {
         println!("Playlist mode (output: `{}`)", playlist_file);
         let mut player = player_builder();
@@ -29,45 +41,17 @@ pub fn repl(args: CliArgs) {
             std::fs::File::create(playlist_file)
                 .expect(&format!("Abort: Cannot create writeable file `{}`", playlist_file))
         );
-        prompt(&mut current_line);
-        loop {
-            read_buf[0] = 0;
-            while read_buf[0] == 0 {
-                stdin.read_exact(&mut read_buf).expect("Failed to read stdin");
-            }
-            match read_buf[0] as char {
-                ';' => {
-                    buf.push(read_buf[0]);
-                    writer.write(buf.as_slice()).expect("Failed to write to MPS interpreter");
+        read_loop(&args, &mut state, || {
             match player.save_m3u8(&mut playlist_writer) {
                 Ok(_) => {},
                 Err(e) => eprintln!("{}", e.message()),
             }
-                    buf.clear();
             playlist_writer.flush().expect("Failed to flush playlist to file");
-                    prompt(&mut current_line);
-                },
-                /*
-                '\x27' => break, // ESC key
-                '\x03' => break, // Ctrl+C
-                */
-                _ => buf.push(read_buf[0]),
-            }
-        }
+        });
     } else {
         println!("Playback mode (output: audio device)");
         let ctrl = MpsController::create_repl(player_builder);
-        prompt(&mut current_line);
-        loop {
-            read_buf[0] = 0;
-            while read_buf[0] == 0 {
-                stdin.read_exact(&mut read_buf).expect("Failed to read stdin");
-            }
-            match read_buf[0] as char {
-                ';' => {
-                    buf.push(read_buf[0]);
-                    writer.write(buf.as_slice()).expect("Failed to write to MPS interpreter");
-                    //ctrl.play().expect("Failed to start playback");
+        read_loop(&args, &mut state, || {
             if args.wait {
                 match ctrl.wait_for_empty() {
                     Ok(_) => {},
@@ -78,20 +62,36 @@ pub fn repl(args: CliArgs) {
                     eprintln!("{}", e.message());
                 }
             }
-                    buf.clear();
-                    prompt(&mut current_line);
-                },
-                '\x27' => break, // ESC key
-                '\x03' => break, // Ctrl+C
-                _ => buf.push(read_buf[0]),
+        });
     }
 }
+
+fn read_loop<F: FnMut()>(args: &CliArgs, state: &mut ReplState, mut execute: F) -> ! {
+    let mut read_buf: [u8;1] = [0];
+    prompt(&mut state.line_number, args);
+    loop {
+        read_buf[0] = 0;
+        while read_buf[0] == 0 {
+            // TODO: enable raw mode (char by char) reading of stdin
+            state.stdin.read(&mut read_buf).expect("Failed to read stdin");
+        }
+        match read_buf[0] as char {
+            '\n' => {
+                state.statement_buf.push(read_buf[0]);
+                state.writer.write(state.statement_buf.as_slice())
+                    .expect("Failed to write to MPS interpreter");
+                execute();
+                state.statement_buf.clear();
+                prompt(&mut state.line_number, args);
+            },
+            _ => state.statement_buf.push(read_buf[0]),
+        }
     }
 }
 
 #[inline(always)]
-fn prompt(line: &mut usize) {
-    print!("{} |-> ", line);
+fn prompt(line: &mut usize, args: &CliArgs) {
+    print!("{}{}", line, args.prompt);
     *line += 1;
     std::io::stdout().flush().expect("Failed to flush stdout");
 }