repline: Promote to its own crate!

cl-repl: Major refactor based on the design of typeck.rs

Cargo.toml

@@ -8,6 +8,7 @@ members = [
     "cl-ast",
     "cl-parser",
     "cl-lexer",
+    "repline",
 ]
 resolver = "2"
 

cl-repl/Cargo.toml

@@ -15,9 +15,8 @@ cl-lexer = { path = "../cl-lexer" }
 cl-token = { path = "../cl-token" }
 cl-parser = { path = "../cl-parser" }
 cl-interpret = { path = "../cl-interpret" }
-crossterm = "0.27.0"
+repline = { path = "../repline" }
 argh = "0.1.12"
 
 [dev-dependencies]
-cl-structures = { path = "../cl-structures" }
 cl-typeck = { path = "../cl-typeck" }

cl-repl/examples/typeck.rs

@@ -4,10 +4,10 @@ use cl_ast::{
 };
 use cl_lexer::Lexer;
 use cl_parser::Parser;
-use cl_repl::repline::{error::Error as RlError, Repline};
 use cl_typeck::{
     definition::Def, name_collector::NameCollectable, project::Project, type_resolver::resolve,
 };
+use repline::{error::Error as RlError, prebaked::*};
 use std::error::Error;
 
 // Path to display in standard library errors
@@ -40,53 +40,21 @@ fn main() -> Result<(), Box<dyn Error>> {
 
     unsafe { TREES.push(code) }.collect_in_root(&mut prj)?;
 
-    main_menu(&mut prj)
-}
-
-pub enum Response {
-    Accept,
-    Deny,
-    Break,
-}
-
-fn read_and(
-    color: &str,
-    begin: &str,
-    mut f: impl FnMut(&str) -> Result<Response, Box<dyn Error>>,
-) -> Result<(), Box<dyn Error>> {
-    let mut rl = Repline::new(color, begin, "? >");
-    loop {
-        let line = match rl.read() {
-            Err(RlError::CtrlC(_)) => break,
-            Err(RlError::CtrlD(line)) => {
-                rl.deny();
-                line
-            }
-            Ok(line) => line,
-            Err(e) => Err(e)?,
-        };
-        print!("\x1b[G\x1b[J");
-        match f(&line) {
-            Ok(Response::Accept) => rl.accept(),
-            Ok(Response::Deny) => rl.deny(),
-            Ok(Response::Break) => break,
-            Err(e) => print!("\x1b[40G\x1bJ\x1b[91m{e}\x1b[0m"),
-        }
-    }
+    main_menu(&mut prj)?;
     Ok(())
 }
 
-fn main_menu(prj: &mut Project) -> Result<(), Box<dyn Error>> {
+fn main_menu(prj: &mut Project) -> Result<(), RlError> {
     banner();
-    read_and(C_MAIN, "mu>", |line| {
+    read_and(C_MAIN, "mu>", "? >", |line| {
         match line.trim() {
-            "c" | "code" => enter_code(prj),
-            "clear" => clear(),
+            "c" | "code" => enter_code(prj)?,
+            "clear" => clear()?,
             "e" | "exit" => return Ok(Response::Break),
             "l" | "list" => list_types(prj),
-            "q" | "query" => query_type_expression(prj),
-            "r" | "resolve" => resolve_all(prj),
-            "d" | "desugar" => live_desugar(),
+            "q" | "query" => query_type_expression(prj)?,
+            "r" | "resolve" => resolve_all(prj)?,
+            "d" | "desugar" => live_desugar()?,
             "h" | "help" => {
                 println!(
                     "Valid commands are:
@@ -102,12 +70,12 @@ fn main_menu(prj: &mut Project) -> Result<(), Box<dyn Error>> {
             }
             _ => Err(r#"Invalid command. Type "help" to see the list of valid commands."#)?,
         }
-        .map(|_| Response::Accept)
+        Ok(Response::Accept)
     })
 }
 
-fn enter_code(prj: &mut Project) -> Result<(), Box<dyn Error>> {
-    read_and(C_CODE, "cl>", |line| {
+fn enter_code(prj: &mut Project) -> Result<(), RlError> {
+    read_and(C_CODE, "cl>", "? >", |line| {
         if line.trim().is_empty() {
             return Ok(Response::Break);
         }
@@ -120,8 +88,8 @@ fn enter_code(prj: &mut Project) -> Result<(), Box<dyn Error>> {
     })
 }
 
-fn live_desugar() -> Result<(), Box<dyn Error>> {
-    read_and(C_RESV, "se>", |line| {
+fn live_desugar() -> Result<(), RlError> {
+    read_and(C_RESV, "se>", "? >", |line| {
         let code = Parser::new(Lexer::new(line)).stmt()?;
         println!("Raw, as parsed:\n{C_LISTING}{code}\x1b[0m");
 
@@ -135,8 +103,8 @@ fn live_desugar() -> Result<(), Box<dyn Error>> {
     })
 }
 
-fn query_type_expression(prj: &mut Project) -> Result<(), Box<dyn Error>> {
-    read_and(C_RESV, "ty>", |line| {
+fn query_type_expression(prj: &mut Project) -> Result<(), RlError> {
+    read_and(C_RESV, "ty>", "? >", |line| {
         if line.trim().is_empty() {
             return Ok(Response::Break);
         }
@@ -156,7 +124,7 @@ fn resolve_all(prj: &mut Project) -> Result<(), Box<dyn Error>> {
     Ok(())
 }
 
-fn list_types(prj: &mut Project) -> Result<(), Box<dyn Error>> {
+fn list_types(prj: &mut Project) {
     println!("     name\x1b[30G  type");
     for (idx, Def { name, vis, kind, .. }) in prj.pool.iter().enumerate() {
         print!("{idx:3}: {vis}");
@@ -165,7 +133,6 @@ fn list_types(prj: &mut Project) -> Result<(), Box<dyn Error>> {
         }
         println!("{name}\x1b[30G| {kind}");
     }
-    Ok(())
 }
 
 fn pretty_def(def: &Def, id: impl Into<usize>) {

cl-repl/examples/yaml.rs

@@ -2,7 +2,7 @@
 
 use cl_lexer::Lexer;
 use cl_parser::Parser;
-use cl_repl::repline::{error::Error as RlError, Repline};
+use repline::{error::Error as RlError, Repline};
 use std::error::Error;
 
 fn main() -> Result<(), Box<dyn Error>> {

cl-repl/src/ansi.rs

@@ -0,0 +1,14 @@
+//! ANSI escape sequences
+
+pub const RED: &str = "\x1b[31m";
+pub const GREEN: &str = "\x1b[32m"; // the color of type checker mode
+pub const CYAN: &str = "\x1b[36m";
+pub const BRIGHT_GREEN: &str = "\x1b[92m";
+pub const BRIGHT_BLUE: &str = "\x1b[94m";
+pub const BRIGHT_MAGENTA: &str = "\x1b[95m";
+pub const BRIGHT_CYAN: &str = "\x1b[96m";
+pub const RESET: &str = "\x1b[0m";
+pub const OUTPUT: &str = "\x1b[38;5;117m";
+
+pub const CLEAR_LINES: &str = "\x1b[G\x1b[J";
+pub const CLEAR_ALL: &str = "\x1b[H\x1b[2J";

cl-repl/src/args.rs

@@ -0,0 +1,51 @@
+//! Handles argument parsing (currently using the [argh] crate)
+
+use argh::FromArgs;
+use std::{io::IsTerminal, path::PathBuf, str::FromStr};
+
+/// The Conlang prototype debug interface
+#[derive(Clone, Debug, FromArgs, PartialEq, Eq, PartialOrd, Ord)]
+pub struct Args {
+    /// the main source file
+    #[argh(positional)]
+    pub file: Option<PathBuf>,
+
+    /// files to include
+    #[argh(option, short = 'I')]
+    pub include: Vec<PathBuf>,
+
+    /// the CLI operating mode (`f`mt | `l`ex | `r`un)
+    #[argh(option, short = 'm', default = "Default::default()")]
+    pub mode: Mode,
+
+    /// whether to start the repl (`true` or `false`)
+    #[argh(option, short = 'r', default = "is_terminal()")]
+    pub repl: bool,
+}
+
+/// gets whether stdin AND stdout are a terminal, for pipelining
+pub fn is_terminal() -> bool {
+    std::io::stdin().is_terminal() && std::io::stdout().is_terminal()
+}
+
+/// The CLI's operating mode
+#[derive(Clone, Copy, Debug, Default, PartialEq, Eq, PartialOrd, Ord)]
+pub enum Mode {
+    #[default]
+    Menu,
+    Lex,
+    Fmt,
+    Run,
+}
+
+impl FromStr for Mode {
+    type Err = &'static str;
+    fn from_str(s: &str) -> Result<Self, &'static str> {
+        Ok(match s {
+            "f" | "fmt" | "p" | "pretty" => Mode::Fmt,
+            "l" | "lex" | "tokenize" | "token" => Mode::Lex,
+            "r" | "run" => Mode::Run,
+            _ => Err("Recognized modes are: 'r' \"run\", 'f' \"fmt\", 'l' \"lex\"")?,
+        })
+    }
+}

cl-repl/src/bin/conlang.rs

@@ -1,13 +1,5 @@
-use cl_repl::{cli::run, tools::is_terminal};
-use std::error::Error;
+use cl_repl::cli::run;
 
-fn main() -> Result<(), Box<dyn Error>> {
-    if is_terminal() {
-        println!(
-            "--- {} v{} 💪🦈 ---",
-            env!("CARGO_BIN_NAME"),
-            env!("CARGO_PKG_VERSION"),
-        );
-    }
+fn main() -> Result<(), Box<dyn std::error::Error>> {
     run(argh::from_env())
 }

cl-repl/src/cli.rs

@@ -0,0 +1,89 @@
+//! Implement's the command line interface
+use crate::{
+    args::{Args, Mode},
+    ctx::Context,
+    menu,
+    tools::print_token,
+};
+use cl_interpret::{env::Environment, interpret::Interpret, temp_type_impl::ConValue};
+use cl_lexer::Lexer;
+use cl_parser::Parser;
+use std::{error::Error, path::Path};
+
+/// Run the command line interface
+pub fn run(args: Args) -> Result<(), Box<dyn Error>> {
+    let Args { file, include, mode, repl } = args;
+
+    let mut env = Environment::new();
+    for path in include {
+        load_file(&mut env, path)?;
+    }
+
+    if repl {
+        if let Some(file) = file {
+            load_file(&mut env, file)?;
+        }
+        let mut ctx = Context::with_env(env);
+        match mode {
+            Mode::Menu => menu::main_menu(&mut ctx)?,
+            Mode::Lex => menu::lex(&mut ctx)?,
+            Mode::Fmt => menu::fmt(&mut ctx)?,
+            Mode::Run => menu::run(&mut ctx)?,
+        }
+    } else {
+        let code = match &file {
+            Some(file) => std::fs::read_to_string(file)?,
+            None => std::io::read_to_string(std::io::stdin())?,
+        };
+
+        match mode {
+            Mode::Lex => lex_code(&code, file),
+            Mode::Fmt => fmt_code(&code),
+            Mode::Run | Mode::Menu => run_code(&code, &mut env),
+        }?;
+    }
+    Ok(())
+}
+
+fn load_file(
+    env: &mut Environment,
+    path: impl AsRef<Path>,
+) -> Result<ConValue, Box<dyn Error>> {
+    let file = std::fs::read_to_string(path)?;
+    let code = Parser::new(Lexer::new(&file)).file()?;
+    Ok(env.eval(&code)?)
+}
+
+fn lex_code(code: &str, path: Option<impl AsRef<Path>>) -> Result<(), Box<dyn Error>> {
+    for token in Lexer::new(code) {
+        if let Some(path) = &path {
+            print!("{}:", path.as_ref().display());
+        }
+        match token {
+            Ok(token) => print_token(&token),
+            Err(e) => println!("{e}"),
+        }
+    }
+    Ok(())
+}
+
+fn fmt_code(code: &str) -> Result<(), Box<dyn Error>> {
+    let code = Parser::new(Lexer::new(code)).file()?;
+    println!("{code}");
+    Ok(())
+}
+
+fn run_code(code: &str, env: &mut Environment) -> Result<(), Box<dyn Error>> {
+    let code = Parser::new(Lexer::new(code)).file()?;
+    match code.interpret(env)? {
+        ConValue::Empty => {}
+        ret => println!("{ret}"),
+    }
+    if env.get("main").is_ok() {
+        match env.call("main", &[])? {
+            ConValue::Empty => {}
+            ret => println!("{ret}"),
+        }
+    }
+    Ok(())
+}

cl-repl/src/ctx.rs

@@ -0,0 +1,26 @@
+use cl_interpret::{
+    env::Environment, error::IResult, interpret::Interpret, temp_type_impl::ConValue,
+};
+
+#[derive(Clone, Debug)]
+pub struct Context {
+    pub env: Environment,
+}
+
+impl Context {
+    pub fn new() -> Self {
+        Self { env: Environment::new() }
+    }
+    pub fn with_env(env: Environment) -> Self {
+        Self { env }
+    }
+    pub fn run(&mut self, code: &impl Interpret) -> IResult<ConValue> {
+        code.interpret(&mut self.env)
+    }
+}
+
+impl Default for Context {
+    fn default() -> Self {
+        Self::new()
+    }
+}

cl-repl/src/lib.rs

@@ -1,446 +1,11 @@
-//! Utilities for cl-frontend
+//! The Conlang REPL, based on [repline]
 //! 
-//! # TODO
-//! - [ ] Readline-like line editing
-//! - [ ] Raw mode?
+//! Uses [argh] for argument parsing.
 #![warn(clippy::all)]
 
-pub mod ansi {
-    // ANSI color escape sequences
-    pub const ANSI_RED: &str = "\x1b[31m";
-    pub const ANSI_GREEN: &str = "\x1b[32m"; // the color of type checker mode
-    pub const ANSI_CYAN: &str = "\x1b[36m";
-    // pub const ANSI_BRIGHT_GREEN: &str = "\x1b[92m";
-    pub const ANSI_BRIGHT_BLUE: &str = "\x1b[94m";
-    pub const ANSI_BRIGHT_MAGENTA: &str = "\x1b[95m";
-    // const ANSI_BRIGHT_CYAN: &str = "\x1b[96m";
-    pub const ANSI_RESET: &str = "\x1b[0m";
-    pub const ANSI_OUTPUT: &str = "\x1b[38;5;117m";
-
-    pub const ANSI_CLEAR_LINES: &str = "\x1b[G\x1b[J";
-}
-
-pub mod args {
-    use crate::tools::is_terminal;
-    use argh::FromArgs;
-    use std::{path::PathBuf, str::FromStr};
-
-    /// The Conlang prototype debug interface
-    #[derive(Clone, Debug, FromArgs, PartialEq, Eq, PartialOrd, Ord)]
-    pub struct Args {
-        /// the main source file
-        #[argh(positional)]
-        pub file: Option<PathBuf>,
-
-        /// files to include
-        #[argh(option, short = 'I')]
-        pub include: Vec<PathBuf>,
-
-        /// the Repl mode to start in
-        #[argh(option, short = 'm', default = "Default::default()")]
-        pub mode: Mode,
-
-        /// whether to start the repl (`true` or `false`)
-        #[argh(option, short = 'r', default = "is_terminal()")]
-        pub repl: bool,
-    }
-
-    /// The CLI's operating mode
-    #[derive(Clone, Copy, Debug, Default, PartialEq, Eq, PartialOrd, Ord)]
-    pub enum Mode {
-        Tokenize,
-        Beautify,
-        #[default]
-        Interpret,
-    }
-
-    impl Mode {
-        pub fn ansi_color(self) -> &'static str {
-            use super::ansi::*;
-            match self {
-                Mode::Tokenize => ANSI_BRIGHT_BLUE,
-                Mode::Beautify => ANSI_BRIGHT_MAGENTA,
-                Mode::Interpret => ANSI_CYAN,
-            }
-        }
-    }
-
-    impl FromStr for Mode {
-        type Err = &'static str;
-        fn from_str(s: &str) -> Result<Self, &'static str> {
-            Ok(match s {
-                "i" | "interpret" | "r" | "run" => Mode::Interpret,
-                "b" | "beautify" | "p" | "pretty" => Mode::Beautify,
-                "t" | "tokenize" | "token" => Mode::Tokenize,
-                _ => Err("Recognized modes are: 'r' \"run\", 'p' \"pretty\", 't' \"token\"")?,
-            })
-        }
-    }
-}
-
-pub mod program {
-    use cl_ast::ast;
-    use cl_interpret::{
-        env::Environment, error::IResult, interpret::Interpret, temp_type_impl::ConValue,
-    };
-    use cl_lexer::Lexer;
-    use cl_parser::{error::PResult, Parser};
-    use std::fmt::Display;
-
-    pub struct Parsable;
-
-    pub enum Parsed {
-        File(ast::File),
-        Stmt(ast::Stmt),
-    }
-
-    pub struct Program<'t, Variant> {
-        text: &'t str,
-        data: Variant,
-    }
-    impl<'t, V> Program<'t, V> {
-        pub fn lex(&self) -> Lexer {
-            Lexer::new(self.text)
-        }
-    }
-
-    impl<'t> Program<'t, Parsable> {
-        pub fn new(text: &'t str) -> Self {
-            Self { text, data: Parsable }
-        }
-        pub fn parse(self) -> PResult<Program<'t, Parsed>> {
-            self.parse_file().or_else(|_| self.parse_stmt())
-        }
-        pub fn parse_stmt(&self) -> PResult<Program<'t, Parsed>> {
-            let stmt = Parser::new(self.lex()).stmt()?;
-            // let stmt = WhileElseDesugar.fold_stmt(stmt);
-
-            Ok(Program { data: Parsed::Stmt(stmt), text: self.text })
-        }
-        pub fn parse_file(&self) -> PResult<Program<'t, Parsed>> {
-            let file = Parser::new(self.lex()).file()?;
-            // let file = WhileElseDesugar.fold_file(file);
-
-            Ok(Program { data: Parsed::File(file), text: self.text })
-        }
-    }
-
-    impl<'t> Program<'t, Parsed> {
-        pub fn debug(&self) {
-            match &self.data {
-                Parsed::File(v) => eprintln!("{v:?}"),
-                Parsed::Stmt(v) => eprintln!("{v:?}"),
-            }
-        }
-        pub fn print(&self) {
-            match &self.data {
-                Parsed::File(v) => println!("{v}"),
-                Parsed::Stmt(v) => println!("{v}"),
-            };
-        }
-
-        pub fn run(&self, env: &mut Environment) -> IResult<ConValue> {
-            match &self.data {
-                Parsed::File(v) => v.interpret(env),
-                Parsed::Stmt(v) => v.interpret(env),
-            }
-        }
-    }
-
-    impl<'t> Display for Program<'t, Parsed> {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            match &self.data {
-                Parsed::File(v) => write!(f, "{v}"),
-                Parsed::Stmt(v) => write!(f, "{v}"),
-            }
-        }
-    }
-}
-
-pub mod cli {
-    //! Implement's the command line interface
-    use crate::{
-        args::{Args, Mode},
-        program::{Parsable, Program},
-        repl::Repl,
-        tools::print_token,
-    };
-    use cl_interpret::{env::Environment, temp_type_impl::ConValue};
-    use cl_lexer::Lexer;
-    use cl_parser::Parser;
-    use std::{error::Error, path::Path};
-
-    /// Run the command line interface
-    pub fn run(args: Args) -> Result<(), Box<dyn Error>> {
-        let Args { file, include, mode, repl } = args;
-
-        let mut env = Environment::new();
-        for path in include {
-            load_file(&mut env, path)?;
-        }
-
-        if repl {
-            if let Some(file) = file {
-                load_file(&mut env, file)?;
-            }
-            Repl::with_env(mode, env).repl()
-        } else {
-            let code = match &file {
-                Some(file) => std::fs::read_to_string(file)?,
-                None => std::io::read_to_string(std::io::stdin())?,
-            };
-            let code = Program::new(&code);
-
-            match mode {
-                Mode::Tokenize => tokenize(code, file),
-                Mode::Beautify => beautify(code),
-                Mode::Interpret => interpret(code, &mut env),
-            }?;
-        }
-        Ok(())
-    }
-
-    fn load_file(
-        env: &mut Environment,
-        path: impl AsRef<Path>,
-    ) -> Result<ConValue, Box<dyn Error>> {
-        let file = std::fs::read_to_string(path)?;
-        let code = Parser::new(Lexer::new(&file)).file()?;
-        env.eval(&code).map_err(Into::into)
-    }
-
-    fn tokenize(
-        code: Program<Parsable>,
-        path: Option<impl AsRef<Path>>,
-    ) -> Result<(), Box<dyn Error>> {
-        for token in code.lex() {
-            if let Some(ref path) = path {
-                print!("{}:", path.as_ref().display());
-            }
-            match token {
-                Ok(token) => print_token(&token),
-                Err(e) => println!("{e}"),
-            }
-        }
-        Ok(())
-    }
-
-    fn beautify(code: Program<Parsable>) -> Result<(), Box<dyn Error>> {
-        code.parse()?.print();
-        Ok(())
-    }
-
-    fn interpret(code: Program<Parsable>, env: &mut Environment) -> Result<(), Box<dyn Error>> {
-        match code.parse()?.run(env)? {
-            ConValue::Empty => {}
-            ret => println!("{ret}"),
-        }
-        if env.get("main").is_ok() {
-            match env.call("main", &[])? {
-                ConValue::Empty => {}
-                ret => println!("{ret}"),
-            }
-        }
-        Ok(())
-    }
-}
-
-pub mod repl {
-    use crate::{
-        ansi::*,
-        args::Mode,
-        program::{Parsable, Parsed, Program},
-        tools::print_token,
-    };
-    use cl_interpret::{env::Environment, temp_type_impl::ConValue};
-    use std::fmt::Display;
-
-    /// Implements the interactive interpreter
-    #[derive(Clone, Debug)]
-    pub struct Repl {
-        prompt_again: &'static str, // " ?>"
-        prompt_begin: &'static str, // "cl>"
-        prompt_error: &'static str, // "! >"
-        prompt_succs: &'static str, // " ->"
-        env: Environment,
-        mode: Mode,
-    }
-
-    impl Default for Repl {
-        fn default() -> Self {
-            Self {
-                prompt_begin: "cl>",
-                prompt_again: " ?>",
-                prompt_error: "! >",
-                prompt_succs: " =>",
-                env: Default::default(),
-                mode: Default::default(),
-            }
-        }
-    }
-
-    /// Prompt functions
-    impl Repl {
-        pub fn prompt_result<T: Display, E: Display>(&self, res: Result<T, E>) {
-            match &res {
-                Ok(v) => self.prompt_succs(v),
-                Err(e) => self.prompt_error(e),
-            }
-        }
-        pub fn prompt_error(&self, err: &impl Display) {
-            let Self { prompt_error: prompt, .. } = self;
-            println!("{ANSI_CLEAR_LINES}{ANSI_RED}{prompt} {err}{ANSI_RESET}")
-        }
-        pub fn prompt_succs(&self, value: &impl Display) {
-            let Self { prompt_succs: _prompt, .. } = self;
-            println!("{ANSI_GREEN}{value}{ANSI_RESET}")
-        }
-        /// Resets the cursor to the start of the line, clears the terminal,
-        /// and sets the output color
-        pub fn begin_output(&self) {
-            print!("{ANSI_CLEAR_LINES}{ANSI_OUTPUT}")
-        }
-        pub fn clear_line(&self) {}
-    }
-    /// The actual REPL
-    impl Repl {
-        /// Constructs a new [Repl] with the provided [Mode]
-        pub fn new(mode: Mode) -> Self {
-            Self { mode, ..Default::default() }
-        }
-        /// Constructs a new [Repl] with the provided [Mode] and [Environment]
-        pub fn with_env(mode: Mode, env: Environment) -> Self {
-            Self { mode, env, ..Default::default() }
-        }
-        /// Runs the main REPL loop
-        pub fn repl(&mut self) {
-            use crate::repline::{error::Error, Repline};
-
-            let mut rl = Repline::new(self.mode.ansi_color(), self.prompt_begin, self.prompt_again);
-            fn clear_line() {
-                print!("\x1b[G\x1b[J");
-            }
-            loop {
-                let buf = match rl.read() {
-                    Ok(buf) => buf,
-                    // Ctrl-C: break if current line is empty
-                    Err(Error::CtrlC(buf)) => {
-                        if buf.is_empty() || buf.ends_with('\n') {
-                            return;
-                        }
-                        rl.accept();
-                        println!("Cancelled. (Press Ctrl+C again to quit.)");
-                        continue;
-                    }
-                    // Ctrl-D: reset input, and parse it for errors
-                    Err(Error::CtrlD(buf)) => {
-                        rl.deny();
-                        if let Err(e) = Program::new(&buf).parse() {
-                            clear_line();
-                            self.prompt_error(&e);
-                        }
-                        continue;
-                    }
-                    Err(e) => {
-                        self.prompt_error(&e);
-                        return;
-                    }
-                };
-
-                self.begin_output();
-                if self.command(&buf) {
-                    rl.deny();
-                    rl.set_color(self.mode.ansi_color());
-                    continue;
-                }
-                let code = Program::new(&buf);
-                if self.mode == Mode::Tokenize {
-                    self.tokenize(&code);
-                    rl.deny();
-                    continue;
-                }
-                match code.lex().into_iter().find(|l| l.is_err()) {
-                    None => {}
-                    Some(Ok(_)) => unreachable!(),
-                    Some(Err(error)) => {
-                        rl.deny();
-                        self.prompt_error(&error);
-                        continue;
-                    }
-                }
-                if let Ok(mut code) = code.parse() {
-                    rl.accept();
-                    self.dispatch(&mut code);
-                }
-            }
-        }
-
-        fn help(&self) {
-            println!(
-                "Commands:\n- $tokens\n    Tokenize Mode:\n    Outputs information derived by the Lexer\n- $pretty\n    Beautify Mode:\n    Pretty-prints the input\n- $run\n    Interpret Mode:\n    Interprets the input using Conlang\'s work-in-progress interpreter\n- $mode\n    Prints the current mode\n- $help\n    Prints this help message"
-            );
-        }
-        fn command(&mut self, line: &str) -> bool {
-            let Some(line) = line.trim().strip_prefix('$') else {
-                return false;
-            };
-            if let Ok(mode) = line.parse() {
-                self.mode = mode;
-            } else {
-                match line {
-                    "$run" => self.mode = Mode::Interpret,
-                    "mode" => println!("{:?} Mode", self.mode),
-                    "help" => self.help(),
-                    _ => return false,
-                }
-            }
-            true
-        }
-        /// Dispatches calls to repl functions based on the program
-        fn dispatch(&mut self, code: &mut Program<Parsed>) {
-            match self.mode {
-                Mode::Tokenize => {}
-                Mode::Beautify => self.beautify(code),
-                Mode::Interpret => self.interpret(code),
-            }
-        }
-        fn tokenize(&mut self, code: &Program<Parsable>) {
-            for token in code.lex() {
-                match token {
-                    Ok(token) => print_token(&token),
-                    Err(e) => println!("{e}"),
-                }
-            }
-        }
-        fn interpret(&mut self, code: &Program<Parsed>) {
-            match code.run(&mut self.env) {
-                Ok(ConValue::Empty) => {}
-                res => self.prompt_result(res),
-            }
-        }
-        fn beautify(&mut self, code: &Program<Parsed>) {
-            code.print()
-        }
-    }
-}
-
-pub mod tools {
-    use cl_token::Token;
-    use std::io::IsTerminal;
-    /// Prints a token in the particular way cl-repl does
-    pub fn print_token(t: &Token) {
-        println!(
-            "{:02}:{:02}: {:#19} │{}│",
-            t.line(),
-            t.col(),
-            t.ty(),
-            t.data(),
-        )
-    }
-    /// gets whether stdin AND stdout are a terminal, for pipelining
-    pub fn is_terminal() -> bool {
-        std::io::stdin().is_terminal() && std::io::stdout().is_terminal()
-    }
-}
-
-pub mod repline;
+pub mod ansi;
+pub mod args;
+pub mod cli;
+pub mod ctx;
+pub mod menu;
+pub mod tools;

cl-repl/src/menu.rs

@@ -0,0 +1,76 @@
+use crate::{ansi, ctx};
+use cl_lexer::Lexer;
+use cl_parser::Parser;
+use repline::{error::ReplResult, prebaked::*};
+
+fn clear() {
+    println!("{}", ansi::CLEAR_ALL);
+    banner()
+}
+
+pub fn banner() {
+    println!("--- conlang v{} 💪🦈 ---\n", env!("CARGO_PKG_VERSION"))
+}
+
+/// Presents a selection interface to the user
+pub fn main_menu(ctx: &mut ctx::Context) -> ReplResult<()> {
+    banner();
+    read_and(ansi::GREEN, "mu>", " ?>", |line| {
+        match line.trim() {
+            "clear" => clear(),
+            "l" | "lex" => lex(ctx)?,
+            "f" | "fmt" => fmt(ctx)?,
+            "r" | "run" => run(ctx)?,
+            "q" | "quit" => return Ok(Response::Break),
+            "h" | "help" => println!(
+                "Valid commands
+    lex     (l): Spin up a lexer, and lex some lines
+    fmt     (f): Format the input
+    run     (r): Enter the REPL, and evaluate some statements
+    help    (h): Print this list
+    quit    (q): Exit the program"
+            ),
+            _ => Err("Unknown command. Type \"help\" for help")?,
+        }
+        Ok(Response::Accept)
+    })
+}
+
+pub fn run(ctx: &mut ctx::Context) -> ReplResult<()> {
+    read_and(ansi::CYAN, "cl>", " ?>", |line| {
+        let code = Parser::new(Lexer::new(line)).stmt()?;
+
+        print!("{}", ansi::OUTPUT);
+        match ctx.run(&code) {
+            Ok(v) => println!("{}{v}", ansi::RESET),
+            Err(e) => println!("{}! > {e}{}", ansi::RED, ansi::RESET),
+        }
+        Ok(Response::Accept)
+    })
+}
+
+pub fn lex(_ctx: &mut ctx::Context) -> ReplResult<()> {
+    read_and(ansi::BRIGHT_BLUE, "lx>", " ?>", |line| {
+        for token in Lexer::new(line) {
+            match token {
+                Ok(token) => crate::tools::print_token(&token),
+                Err(e) => eprintln!("! > {}{e}{}", ansi::RED, ansi::RESET),
+            }
+        }
+
+        Ok(Response::Accept)
+    })
+}
+
+pub fn fmt(_ctx: &mut ctx::Context) -> ReplResult<()> {
+    read_and(ansi::BRIGHT_MAGENTA, "cl>", " ?>", |line| {
+        let mut p = Parser::new(Lexer::new(line));
+
+        match p.stmt() {
+            Ok(code) => println!("{}{code}{}", ansi::OUTPUT, ansi::RESET),
+            Err(e) => Err(e)?,
+        }
+
+        Ok(Response::Accept)
+    })
+}

cl-repl/src/repline.rs

@@ -1,607 +0,0 @@
-//! A small pseudo-multiline editing library
-// #![allow(unused)]
-
-pub mod error {
-    /// Result type for Repline
-    pub type ReplResult<T> = std::result::Result<T, Error>;
-    /// Borrowed error (does not implement [Error](std::error::Error)!)
-    #[derive(Debug)]
-    pub enum Error {
-        /// User broke with Ctrl+C
-        CtrlC(String),
-        /// User broke with Ctrl+D
-        CtrlD(String),
-        /// Invalid unicode codepoint
-        BadUnicode(u32),
-        /// Error came from [std::io]
-        IoFailure(std::io::Error),
-        /// End of input
-        EndOfInput,
-    }
-
-    impl std::error::Error for Error {}
-    impl std::fmt::Display for Error {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            match self {
-                Error::CtrlC(_) => write!(f, "Ctrl+C"),
-                Error::CtrlD(_) => write!(f, "Ctrl+D"),
-                Error::BadUnicode(u) => write!(f, "0x{u:x} is not a valid unicode codepoint"),
-                Error::IoFailure(s) => write!(f, "{s}"),
-                Error::EndOfInput => write!(f, "End of input"),
-            }
-        }
-    }
-    impl From<std::io::Error> for Error {
-        fn from(value: std::io::Error) -> Self {
-            Self::IoFailure(value)
-        }
-    }
-}
-
-pub mod chars {
-    //! Converts an <code>[Iterator]<Item = [u8]></code> into an
-    //! <code>[Iterator]<Item = [char]></code>
-
-    use super::error::*;
-
-    /// Converts an <code>[Iterator]<Item = [u8]></code> into an
-    /// <code>[Iterator]<Item = [char]></code>
-    #[derive(Clone, Debug)]
-    pub struct Chars<I: Iterator<Item = u8>>(pub I);
-    impl<I: Iterator<Item = u8>> Chars<I> {
-        pub fn new(bytes: I) -> Self {
-            Self(bytes)
-        }
-    }
-    impl<I: Iterator<Item = u8>> Iterator for Chars<I> {
-        type Item = ReplResult<char>;
-        fn next(&mut self) -> Option<Self::Item> {
-            let Self(bytes) = self;
-            let start = bytes.next()? as u32;
-            let (mut out, count) = match start {
-                start if start & 0x80 == 0x00 => (start, 0), // ASCII valid range
-                start if start & 0xe0 == 0xc0 => (start & 0x1f, 1), // 1 continuation byte
-                start if start & 0xf0 == 0xe0 => (start & 0x0f, 2), // 2 continuation bytes
-                start if start & 0xf8 == 0xf0 => (start & 0x07, 3), // 3 continuation bytes
-                _ => return None,
-            };
-            for _ in 0..count {
-                let cont = bytes.next()? as u32;
-                if cont & 0xc0 != 0x80 {
-                    return None;
-                }
-                out = out << 6 | (cont & 0x3f);
-            }
-            Some(char::from_u32(out).ok_or(Error::BadUnicode(out)))
-        }
-    }
-}
-
-pub mod flatten {
-    //! Flattens an [Iterator] returning [`Result<T, E>`](Result) or [`Option<T>`](Option)
-    //! into a *non-[FusedIterator](std::iter::FusedIterator)* over `T`
-
-    /// Flattens an [Iterator] returning [`Result<T, E>`](Result) or [`Option<T>`](Option)
-    /// into a *non-[FusedIterator](std::iter::FusedIterator)* over `T`
-    pub struct Flatten<T, I: Iterator<Item = T>>(pub I);
-    impl<T, E, I: Iterator<Item = Result<T, E>>> Iterator for Flatten<Result<T, E>, I> {
-        type Item = T;
-        fn next(&mut self) -> Option<Self::Item> {
-            self.0.next()?.ok()
-        }
-    }
-    impl<T, I: Iterator<Item = Option<T>>> Iterator for Flatten<Option<T>, I> {
-        type Item = T;
-        fn next(&mut self) -> Option<Self::Item> {
-            self.0.next()?
-        }
-    }
-}
-
-pub mod raw {
-    //! Sets the terminal to [`raw`] mode for the duration of the returned object's lifetime.
-
-    /// Sets the terminal to raw mode for the duration of the returned object's lifetime.
-    pub fn raw() -> impl Drop {
-        Raw::default()
-    }
-    struct Raw();
-    impl Default for Raw {
-        fn default() -> Self {
-            std::thread::yield_now();
-            crossterm::terminal::enable_raw_mode()
-                .expect("should be able to transition into raw mode");
-            Raw()
-        }
-    }
-    impl Drop for Raw {
-        fn drop(&mut self) {
-            crossterm::terminal::disable_raw_mode()
-                .expect("should be able to transition out of raw mode");
-            // std::thread::yield_now();
-        }
-    }
-}
-
-mod out {
-    #![allow(unused)]
-    use std::io::{Result, Write};
-
-    /// A [Writer](Write) that flushes after every wipe
-    #[derive(Clone, Debug)]
-    pub(super) struct EagerWriter<W: Write> {
-        out: W,
-    }
-    impl<W: Write> EagerWriter<W> {
-        pub fn new(writer: W) -> Self {
-            Self { out: writer }
-        }
-    }
-    impl<W: Write> Write for EagerWriter<W> {
-        fn write(&mut self, buf: &[u8]) -> Result<usize> {
-            let out = self.out.write(buf)?;
-            self.out.flush()?;
-            Ok(out)
-        }
-        fn flush(&mut self) -> Result<()> {
-            self.out.flush()
-        }
-    }
-}
-
-use self::{chars::Chars, editor::Editor, error::*, flatten::Flatten, raw::raw};
-use std::{
-    collections::VecDeque,
-    io::{stdout, Bytes, Read, Result, Write},
-};
-
-pub struct Repline<'a, R: Read> {
-    input: Chars<Flatten<Result<u8>, Bytes<R>>>,
-
-    history: VecDeque<String>, // previous lines
-    hindex: usize,             // current index into the history buffer
-
-    ed: Editor<'a>, // the current line buffer
-}
-
-impl<'a, R: Read> Repline<'a, R> {
-    /// Constructs a [Repline] with the given [Reader](Read), color, begin, and again prompts.
-    pub fn with_input(input: R, color: &'a str, begin: &'a str, again: &'a str) -> Self {
-        Self {
-            input: Chars(Flatten(input.bytes())),
-            history: Default::default(),
-            hindex: 0,
-            ed: Editor::new(color, begin, again),
-        }
-    }
-    /// Set the terminal prompt color
-    pub fn set_color(&mut self, color: &'a str) {
-        self.ed.color = color
-    }
-    /// Reads in a line, and returns it for validation
-    pub fn read(&mut self) -> ReplResult<String> {
-        const INDENT: &str = "    ";
-        let mut stdout = stdout().lock();
-        let stdout = &mut stdout;
-        let _make_raw = raw();
-        // self.ed.begin_frame(stdout)?;
-        // self.ed.redraw_frame(stdout)?;
-        self.ed.print_head(stdout)?;
-        loop {
-            stdout.flush()?;
-            match self.input.next().ok_or(Error::EndOfInput)?? {
-                // Ctrl+C: End of Text. Immediately exits.
-                // Ctrl+D: End of Transmission. Ends the current line.
-                '\x03' => {
-                    drop(_make_raw);
-                    writeln!(stdout)?;
-                    return Err(Error::CtrlC(self.ed.to_string()));
-                }
-                '\x04' => {
-                    drop(_make_raw);
-                    writeln!(stdout)?;
-                    return Err(Error::CtrlD(self.ed.to_string()));
-                }
-                // Tab: extend line by 4 spaces
-                '\t' => {
-                    self.ed.extend(INDENT.chars(), stdout)?;
-                }
-                // ignore newlines, process line feeds. Not sure how cross-platform this is.
-                '\n' => {}
-                '\r' => {
-                    self.ed.push('\n', stdout)?;
-                    return Ok(self.ed.to_string());
-                }
-                // Ctrl+Backspace in my terminal
-                '\x17' => {
-                    self.ed.erase_word(stdout)?;
-                }
-                // Escape sequence
-                '\x1b' => self.escape(stdout)?,
-                // backspace
-                '\x08' | '\x7f' => {
-                    let ed = &mut self.ed;
-                    if ed.ends_with(INDENT.chars()) {
-                        for _ in 0..INDENT.len() {
-                            ed.pop(stdout)?;
-                        }
-                    } else {
-                        ed.pop(stdout)?;
-                    }
-                }
-                c if c.is_ascii_control() => {
-                    if cfg!(debug_assertions) {
-                        self.ed.extend(c.escape_debug(), stdout)?;
-                    }
-                }
-                c => {
-                    self.ed.push(c, stdout)?;
-                }
-            }
-        }
-    }
-    /// Handle ANSI Escape
-    fn escape<W: Write>(&mut self, w: &mut W) -> ReplResult<()> {
-        match self.input.next().ok_or(Error::EndOfInput)?? {
-            '[' => self.csi(w)?,
-            'O' => todo!("Process alternate character mode"),
-            other => self.ed.extend(other.escape_debug(), w)?,
-        }
-        Ok(())
-    }
-    /// Handle ANSI Control Sequence Introducer
-    fn csi<W: Write>(&mut self, w: &mut W) -> ReplResult<()> {
-        match self.input.next().ok_or(Error::EndOfInput)?? {
-            'A' => {
-                self.hindex = self.hindex.saturating_sub(1);
-                self.restore_history(w)?
-            }
-            'B' => {
-                self.hindex = self.hindex.saturating_add(1).min(self.history.len());
-                self.restore_history(w)?
-            }
-            'C' => self.ed.cursor_forward(1, w)?,
-            'D' => self.ed.cursor_back(1, w)?,
-            'H' => self.ed.home(w)?,
-            'F' => self.ed.end(w)?,
-            '3' => {
-                if let '~' = self.input.next().ok_or(Error::EndOfInput)?? {
-                    let _ = self.ed.delete(w);
-                }
-            }
-            other => {
-                if cfg!(debug_assertions) {
-                    self.ed.extend(other.escape_debug(), w)?;
-                }
-            }
-        }
-        Ok(())
-    }
-    /// Restores the currently selected history
-    pub fn restore_history<W: Write>(&mut self, w: &mut W) -> ReplResult<()> {
-        let Self { history, hindex, ed, .. } = self;
-        ed.undraw(w)?;
-        ed.clear();
-        ed.print_head(w)?;
-        if let Some(history) = history.get(*hindex) {
-            ed.extend(history.chars(), w)?
-        }
-        Ok(())
-    }
-
-    /// Append line to history and clear it
-    pub fn accept(&mut self) {
-        self.history_append(self.ed.iter().collect());
-        self.ed.clear();
-        self.hindex = self.history.len();
-    }
-    /// Append line to history
-    pub fn history_append(&mut self, mut buf: String) {
-        while buf.ends_with(char::is_whitespace) {
-            buf.pop();
-        }
-        if !self.history.contains(&buf) {
-            self.history.push_back(buf)
-        }
-        while self.history.len() > 20 {
-            self.history.pop_front();
-        }
-    }
-    /// Clear the line
-    pub fn deny(&mut self) {
-        self.ed.clear()
-    }
-}
-
-impl<'a> Repline<'a, std::io::Stdin> {
-    pub fn new(color: &'a str, begin: &'a str, again: &'a str) -> Self {
-        Self::with_input(std::io::stdin(), color, begin, again)
-    }
-}
-
-pub mod editor {
-    use crossterm::{cursor::*, execute, queue, style::*, terminal::*};
-    use std::{collections::VecDeque, fmt::Display, io::Write};
-
-    use super::error::{Error, ReplResult};
-
-    fn is_newline(c: &char) -> bool {
-        *c == '\n'
-    }
-
-    fn write_chars<'a, W: Write>(
-        c: impl IntoIterator<Item = &'a char>,
-        w: &mut W,
-    ) -> std::io::Result<()> {
-        for c in c {
-            write!(w, "{c}")?;
-        }
-        Ok(())
-    }
-
-    #[derive(Debug)]
-    pub struct Editor<'a> {
-        head: VecDeque<char>,
-        tail: VecDeque<char>,
-
-        pub color: &'a str,
-        begin: &'a str,
-        again: &'a str,
-    }
-
-    impl<'a> Editor<'a> {
-        pub fn new(color: &'a str, begin: &'a str, again: &'a str) -> Self {
-            Self { head: Default::default(), tail: Default::default(), color, begin, again }
-        }
-        pub fn iter(&self) -> impl Iterator<Item = &char> {
-            self.head.iter()
-        }
-        pub fn undraw<W: Write>(&self, w: &mut W) -> ReplResult<()> {
-            let Self { head, .. } = self;
-            match head.iter().copied().filter(is_newline).count() {
-                0 => write!(w, "\x1b[0G"),
-                lines => write!(w, "\x1b[{}F", lines),
-            }?;
-            queue!(w, Clear(ClearType::FromCursorDown))?;
-            // write!(w, "\x1b[0J")?;
-            Ok(())
-        }
-        pub fn redraw<W: Write>(&self, w: &mut W) -> ReplResult<()> {
-            let Self { head, tail, color, begin, again } = self;
-            write!(w, "{color}{begin}\x1b[0m ")?;
-            // draw head
-            for c in head {
-                match c {
-                    '\n' => write!(w, "\r\n{color}{again}\x1b[0m "),
-                    _ => w.write_all({ *c as u32 }.to_le_bytes().as_slice()),
-                }?
-            }
-            // save cursor
-            execute!(w, SavePosition)?;
-            // draw tail
-            for c in tail {
-                match c {
-                    '\n' => write!(w, "\r\n{color}{again}\x1b[0m "),
-                    _ => write!(w, "{c}"),
-                }?
-            }
-            // restore cursor
-            execute!(w, RestorePosition)?;
-            Ok(())
-        }
-        pub fn prompt<W: Write>(&self, w: &mut W) -> ReplResult<()> {
-            let Self { head, color, begin, again, .. } = self;
-            queue!(
-                w,
-                MoveToColumn(0),
-                Print(color),
-                Print(if head.is_empty() { begin } else { again }),
-                ResetColor,
-                Print(' '),
-            )?;
-            Ok(())
-        }
-        pub fn print_head<W: Write>(&self, w: &mut W) -> ReplResult<()> {
-            self.prompt(w)?;
-            write_chars(
-                self.head.iter().skip(
-                    self.head
-                        .iter()
-                        .rposition(is_newline)
-                        .unwrap_or(self.head.len())
-                        + 1,
-                ),
-                w,
-            )?;
-            Ok(())
-        }
-        pub fn print_tail<W: Write>(&self, w: &mut W) -> ReplResult<()> {
-            let Self { tail, .. } = self;
-            queue!(w, SavePosition, Clear(ClearType::UntilNewLine))?;
-            write_chars(tail.iter().take_while(|&c| !is_newline(c)), w)?;
-            queue!(w, RestorePosition)?;
-            Ok(())
-        }
-        pub fn push<W: Write>(&mut self, c: char, w: &mut W) -> ReplResult<()> {
-            // Tail optimization: if the tail is empty,
-            //we don't have to undraw and redraw on newline
-            if self.tail.is_empty() {
-                self.head.push_back(c);
-                match c {
-                    '\n' => {
-                        write!(w, "\r\n")?;
-                        self.print_head(w)?;
-                    }
-                    c => {
-                        queue!(w, Print(c))?;
-                    }
-                };
-                return Ok(());
-            }
-
-            if '\n' == c {
-                self.undraw(w)?;
-            }
-            self.head.push_back(c);
-            match c {
-                '\n' => self.redraw(w)?,
-                _ => {
-                    write!(w, "{c}")?;
-                    self.print_tail(w)?;
-                }
-            }
-            Ok(())
-        }
-        pub fn pop<W: Write>(&mut self, w: &mut W) -> ReplResult<Option<char>> {
-            if let Some('\n') = self.head.back() {
-                self.undraw(w)?;
-            }
-            let c = self.head.pop_back();
-            // if the character was a newline, we need to go back a line
-            match c {
-                Some('\n') => self.redraw(w)?,
-                Some(_) => {
-                    // go back a char
-                    queue!(w, MoveLeft(1), Print(' '), MoveLeft(1))?;
-                    self.print_tail(w)?;
-                }
-                None => {}
-            }
-            Ok(c)
-        }
-
-        pub fn extend<T: IntoIterator<Item = char>, W: Write>(
-            &mut self,
-            iter: T,
-            w: &mut W,
-        ) -> ReplResult<()> {
-            for c in iter {
-                self.push(c, w)?;
-            }
-            Ok(())
-        }
-
-        pub fn restore(&mut self, s: &str) {
-            self.clear();
-            self.head.extend(s.chars())
-        }
-        pub fn clear(&mut self) {
-            self.head.clear();
-            self.tail.clear();
-        }
-        pub fn delete<W: Write>(&mut self, w: &mut W) -> ReplResult<char> {
-            match self.tail.front() {
-                Some('\n') => {
-                    self.undraw(w)?;
-                    let out = self.tail.pop_front();
-                    self.redraw(w)?;
-                    out
-                }
-                _ => {
-                    let out = self.tail.pop_front();
-                    self.print_tail(w)?;
-                    out
-                }
-            }
-            .ok_or(Error::EndOfInput)
-        }
-        pub fn erase_word<W: Write>(&mut self, w: &mut W) -> ReplResult<()> {
-            while self.pop(w)?.filter(|c| !c.is_whitespace()).is_some() {}
-            Ok(())
-        }
-        pub fn len(&self) -> usize {
-            self.head.len() + self.tail.len()
-        }
-        pub fn is_empty(&self) -> bool {
-            self.head.is_empty() && self.tail.is_empty()
-        }
-        pub fn ends_with(&self, iter: impl DoubleEndedIterator<Item = char>) -> bool {
-            let mut iter = iter.rev();
-            let mut head = self.head.iter().rev();
-            loop {
-                match (iter.next(), head.next()) {
-                    (None, _) => break true,
-                    (Some(_), None) => break false,
-                    (Some(a), Some(b)) if a != *b => break false,
-                    (Some(_), Some(_)) => continue,
-                }
-            }
-        }
-        /// Moves the cursor back `steps` steps
-        pub fn cursor_back<W: Write>(&mut self, steps: usize, w: &mut W) -> ReplResult<()> {
-            for _ in 0..steps {
-                if let Some('\n') = self.head.back() {
-                    self.undraw(w)?;
-                }
-                let Some(c) = self.head.pop_back() else {
-                    return Ok(());
-                };
-                self.tail.push_front(c);
-                match c {
-                    '\n' => self.redraw(w)?,
-                    _ => queue!(w, MoveLeft(1))?,
-                }
-            }
-            Ok(())
-        }
-        /// Moves the cursor forward `steps` steps
-        pub fn cursor_forward<W: Write>(&mut self, steps: usize, w: &mut W) -> ReplResult<()> {
-            for _ in 0..steps {
-                if let Some('\n') = self.tail.front() {
-                    self.undraw(w)?
-                }
-                let Some(c) = self.tail.pop_front() else {
-                    return Ok(());
-                };
-                self.head.push_back(c);
-                match c {
-                    '\n' => self.redraw(w)?,
-                    _ => queue!(w, MoveRight(1))?,
-                }
-            }
-            Ok(())
-        }
-        /// Goes to the beginning of the current line
-        pub fn home<W: Write>(&mut self, w: &mut W) -> ReplResult<()> {
-            loop {
-                match self.head.back() {
-                    Some('\n') | None => break Ok(()),
-                    Some(_) => self.cursor_back(1, w)?,
-                }
-            }
-        }
-        /// Goes to the end of the current line
-        pub fn end<W: Write>(&mut self, w: &mut W) -> ReplResult<()> {
-            loop {
-                match self.tail.front() {
-                    Some('\n') | None => break Ok(()),
-                    Some(_) => self.cursor_forward(1, w)?,
-                }
-            }
-        }
-    }
-
-    impl<'a, 'e> IntoIterator for &'e Editor<'a> {
-        type Item = &'e char;
-        type IntoIter = std::iter::Chain<
-            std::collections::vec_deque::Iter<'e, char>,
-            std::collections::vec_deque::Iter<'e, char>,
-        >;
-        fn into_iter(self) -> Self::IntoIter {
-            self.head.iter().chain(self.tail.iter())
-        }
-    }
-    impl<'a> Display for Editor<'a> {
-        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-            use std::fmt::Write;
-            let Self { head, tail, .. } = self;
-            for c in head {
-                f.write_char(*c)?;
-            }
-            for c in tail {
-                f.write_char(*c)?;
-            }
-            Ok(())
-        }
-    }
-}

cl-repl/src/tools.rs

@@ -0,0 +1,11 @@
+use cl_token::Token;
+/// Prints a token in the particular way [cl-repl](crate) does
+pub fn print_token(t: &Token) {
+    println!(
+        "{:02}:{:02}: {:#19} │{}│",
+        t.line(),
+        t.col(),
+        t.ty(),
+        t.data(),
+    )
+}

repline/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "repline"
+repository.workspace = true
+version.workspace = true
+authors.workspace = true
+edition.workspace = true
+license.workspace = true
+publish.workspace = true
+
+[dependencies]
+crossterm = "0.27.0"

repline/src/editor.rs

@@ -0,0 +1,283 @@
+//! The [Editor]
+
+use crossterm::{cursor::*, execute, queue, style::*, terminal::*};
+use std::{collections::VecDeque, fmt::Display, io::Write};
+
+use super::error::{Error, ReplResult};
+
+fn is_newline(c: &char) -> bool {
+    *c == '\n'
+}
+
+fn write_chars<'a, W: Write>(
+    c: impl IntoIterator<Item = &'a char>,
+    w: &mut W,
+) -> std::io::Result<()> {
+    for c in c {
+        write!(w, "{c}")?;
+    }
+    Ok(())
+}
+
+#[derive(Clone, Debug)]
+pub struct Editor<'a> {
+    head: VecDeque<char>,
+    tail: VecDeque<char>,
+
+    pub color: &'a str,
+    begin: &'a str,
+    again: &'a str,
+}
+
+impl<'a> Editor<'a> {
+    pub fn new(color: &'a str, begin: &'a str, again: &'a str) -> Self {
+        Self { head: Default::default(), tail: Default::default(), color, begin, again }
+    }
+    pub fn iter(&self) -> impl Iterator<Item = &char> {
+        let Self { head, tail, .. } = self;
+        head.iter().chain(tail.iter())
+    }
+    pub fn undraw<W: Write>(&self, w: &mut W) -> ReplResult<()> {
+        let Self { head, .. } = self;
+        match head.iter().copied().filter(is_newline).count() {
+            0 => write!(w, "\x1b[0G"),
+            lines => write!(w, "\x1b[{}F", lines),
+        }?;
+        queue!(w, Clear(ClearType::FromCursorDown))?;
+        // write!(w, "\x1b[0J")?;
+        Ok(())
+    }
+    pub fn redraw<W: Write>(&self, w: &mut W) -> ReplResult<()> {
+        let Self { head, tail, color, begin, again } = self;
+        write!(w, "{color}{begin}\x1b[0m ")?;
+        // draw head
+        for c in head {
+            match c {
+                '\n' => write!(w, "\r\n{color}{again}\x1b[0m "),
+                _ => w.write_all({ *c as u32 }.to_le_bytes().as_slice()),
+            }?
+        }
+        // save cursor
+        execute!(w, SavePosition)?;
+        // draw tail
+        for c in tail {
+            match c {
+                '\n' => write!(w, "\r\n{color}{again}\x1b[0m "),
+                _ => write!(w, "{c}"),
+            }?
+        }
+        // restore cursor
+        execute!(w, RestorePosition)?;
+        Ok(())
+    }
+    pub fn prompt<W: Write>(&self, w: &mut W) -> ReplResult<()> {
+        let Self { head, color, begin, again, .. } = self;
+        queue!(
+            w,
+            MoveToColumn(0),
+            Print(color),
+            Print(if head.is_empty() { begin } else { again }),
+            ResetColor,
+            Print(' '),
+        )?;
+        Ok(())
+    }
+    pub fn print_head<W: Write>(&self, w: &mut W) -> ReplResult<()> {
+        self.prompt(w)?;
+        write_chars(
+            self.head.iter().skip(
+                self.head
+                    .iter()
+                    .rposition(is_newline)
+                    .unwrap_or(self.head.len())
+                    + 1,
+            ),
+            w,
+        )?;
+        Ok(())
+    }
+    pub fn print_tail<W: Write>(&self, w: &mut W) -> ReplResult<()> {
+        let Self { tail, .. } = self;
+        queue!(w, SavePosition, Clear(ClearType::UntilNewLine))?;
+        write_chars(tail.iter().take_while(|&c| !is_newline(c)), w)?;
+        queue!(w, RestorePosition)?;
+        Ok(())
+    }
+    pub fn push<W: Write>(&mut self, c: char, w: &mut W) -> ReplResult<()> {
+        // Tail optimization: if the tail is empty,
+        //we don't have to undraw and redraw on newline
+        if self.tail.is_empty() {
+            self.head.push_back(c);
+            match c {
+                '\n' => {
+                    write!(w, "\r\n")?;
+                    self.print_head(w)?;
+                }
+                c => {
+                    queue!(w, Print(c))?;
+                }
+            };
+            return Ok(());
+        }
+
+        if '\n' == c {
+            self.undraw(w)?;
+        }
+        self.head.push_back(c);
+        match c {
+            '\n' => self.redraw(w)?,
+            _ => {
+                write!(w, "{c}")?;
+                self.print_tail(w)?;
+            }
+        }
+        Ok(())
+    }
+    pub fn pop<W: Write>(&mut self, w: &mut W) -> ReplResult<Option<char>> {
+        if let Some('\n') = self.head.back() {
+            self.undraw(w)?;
+        }
+        let c = self.head.pop_back();
+        // if the character was a newline, we need to go back a line
+        match c {
+            Some('\n') => self.redraw(w)?,
+            Some(_) => {
+                // go back a char
+                queue!(w, MoveLeft(1), Print(' '), MoveLeft(1))?;
+                self.print_tail(w)?;
+            }
+            None => {}
+        }
+        Ok(c)
+    }
+
+    pub fn extend<T: IntoIterator<Item = char>, W: Write>(
+        &mut self,
+        iter: T,
+        w: &mut W,
+    ) -> ReplResult<()> {
+        for c in iter {
+            self.push(c, w)?;
+        }
+        Ok(())
+    }
+
+    pub fn restore(&mut self, s: &str) {
+        self.clear();
+        self.head.extend(s.chars())
+    }
+    pub fn clear(&mut self) {
+        self.head.clear();
+        self.tail.clear();
+    }
+    pub fn delete<W: Write>(&mut self, w: &mut W) -> ReplResult<char> {
+        match self.tail.front() {
+            Some('\n') => {
+                self.undraw(w)?;
+                let out = self.tail.pop_front();
+                self.redraw(w)?;
+                out
+            }
+            _ => {
+                let out = self.tail.pop_front();
+                self.print_tail(w)?;
+                out
+            }
+        }
+        .ok_or(Error::EndOfInput)
+    }
+    pub fn erase_word<W: Write>(&mut self, w: &mut W) -> ReplResult<()> {
+        while self.pop(w)?.filter(|c| !c.is_whitespace()).is_some() {}
+        Ok(())
+    }
+    pub fn len(&self) -> usize {
+        self.head.len() + self.tail.len()
+    }
+    pub fn is_empty(&self) -> bool {
+        self.head.is_empty() && self.tail.is_empty()
+    }
+    pub fn ends_with(&self, iter: impl DoubleEndedIterator<Item = char>) -> bool {
+        let mut iter = iter.rev();
+        let mut head = self.head.iter().rev();
+        loop {
+            match (iter.next(), head.next()) {
+                (None, _) => break true,
+                (Some(_), None) => break false,
+                (Some(a), Some(b)) if a != *b => break false,
+                (Some(_), Some(_)) => continue,
+            }
+        }
+    }
+    /// Moves the cursor back `steps` steps
+    pub fn cursor_back<W: Write>(&mut self, steps: usize, w: &mut W) -> ReplResult<()> {
+        for _ in 0..steps {
+            if let Some('\n') = self.head.back() {
+                self.undraw(w)?;
+            }
+            let Some(c) = self.head.pop_back() else {
+                return Ok(());
+            };
+            self.tail.push_front(c);
+            match c {
+                '\n' => self.redraw(w)?,
+                _ => queue!(w, MoveLeft(1))?,
+            }
+        }
+        Ok(())
+    }
+    /// Moves the cursor forward `steps` steps
+    pub fn cursor_forward<W: Write>(&mut self, steps: usize, w: &mut W) -> ReplResult<()> {
+        for _ in 0..steps {
+            if let Some('\n') = self.tail.front() {
+                self.undraw(w)?
+            }
+            let Some(c) = self.tail.pop_front() else {
+                return Ok(());
+            };
+            self.head.push_back(c);
+            match c {
+                '\n' => self.redraw(w)?,
+                _ => queue!(w, MoveRight(1))?,
+            }
+        }
+        Ok(())
+    }
+    /// Goes to the beginning of the current line
+    pub fn home<W: Write>(&mut self, w: &mut W) -> ReplResult<()> {
+        loop {
+            match self.head.back() {
+                Some('\n') | None => break Ok(()),
+                Some(_) => self.cursor_back(1, w)?,
+            }
+        }
+    }
+    /// Goes to the end of the current line
+    pub fn end<W: Write>(&mut self, w: &mut W) -> ReplResult<()> {
+        loop {
+            match self.tail.front() {
+                Some('\n') | None => break Ok(()),
+                Some(_) => self.cursor_forward(1, w)?,
+            }
+        }
+    }
+}
+
+impl<'a, 'e> IntoIterator for &'e Editor<'a> {
+    type Item = &'e char;
+    type IntoIter = std::iter::Chain<
+        std::collections::vec_deque::Iter<'e, char>,
+        std::collections::vec_deque::Iter<'e, char>,
+    >;
+    fn into_iter(self) -> Self::IntoIter {
+        self.head.iter().chain(self.tail.iter())
+    }
+}
+impl<'a> Display for Editor<'a> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        use std::fmt::Write;
+        for c in self.iter() {
+            f.write_char(*c)?;
+        }
+        Ok(())
+    }
+}

repline/src/error.rs

@@ -0,0 +1,42 @@
+use crate::iter::chars::BadUnicode;
+
+/// Result type for Repline
+pub type ReplResult<T> = std::result::Result<T, Error>;
+/// Borrowed error (does not implement [Error](std::error::Error)!)
+#[derive(Debug)]
+pub enum Error {
+    /// User broke with Ctrl+C
+    CtrlC(String),
+    /// User broke with Ctrl+D
+    CtrlD(String),
+    /// Invalid unicode codepoint
+    BadUnicode(u32),
+    /// Error came from [std::io]
+    IoFailure(std::io::Error),
+    /// End of input
+    EndOfInput,
+}
+
+impl std::error::Error for Error {}
+impl std::fmt::Display for Error {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Error::CtrlC(_) => write!(f, "Ctrl+C"),
+            Error::CtrlD(_) => write!(f, "Ctrl+D"),
+            Error::BadUnicode(u) => write!(f, "\\u{{{u:x}}} is not a valid unicode codepoint"),
+            Error::IoFailure(s) => write!(f, "{s}"),
+            Error::EndOfInput => write!(f, "End of input"),
+        }
+    }
+}
+impl From<std::io::Error> for Error {
+    fn from(value: std::io::Error) -> Self {
+        Self::IoFailure(value)
+    }
+}
+impl From<BadUnicode> for Error {
+    fn from(value: BadUnicode) -> Self {
+        let BadUnicode(code) = value;
+        Self::BadUnicode(code)
+    }
+}

repline/src/iter.rs

@@ -0,0 +1,68 @@
+//! Shmancy iterator adapters
+
+pub use chars::Chars;
+pub use flatten::Flatten;
+
+pub mod chars {
+    //! Converts an <code>[Iterator]<Item = [u8]></code> into an
+    //! <code>[Iterator]<Item = [Result]<[char], [BadUnicode]>></code>
+
+    /// Invalid unicode codepoint found when iterating over [Chars]
+    #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+    pub struct BadUnicode(pub u32);
+    impl std::error::Error for BadUnicode {}
+    impl std::fmt::Display for BadUnicode {
+        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+            let Self(code) = self;
+            write!(f, "Bad unicode: {code}")
+        }
+    }
+
+    /// Converts an <code>[Iterator]<Item = [u8]></code> into an
+    /// <code>[Iterator]<Item = [char]></code>
+    #[derive(Clone, Debug)]
+    pub struct Chars<I: Iterator<Item = u8>>(pub I);
+    impl<I: Iterator<Item = u8>> Iterator for Chars<I> {
+        type Item = Result<char, BadUnicode>;
+        fn next(&mut self) -> Option<Self::Item> {
+            let Self(bytes) = self;
+            let start = bytes.next()? as u32;
+            let (mut out, count) = match start {
+                start if start & 0x80 == 0x00 => (start, 0), // ASCII valid range
+                start if start & 0xe0 == 0xc0 => (start & 0x1f, 1), // 1 continuation byte
+                start if start & 0xf0 == 0xe0 => (start & 0x0f, 2), // 2 continuation bytes
+                start if start & 0xf8 == 0xf0 => (start & 0x07, 3), // 3 continuation bytes
+                _ => return None,
+            };
+            for _ in 0..count {
+                let cont = bytes.next()? as u32;
+                if cont & 0xc0 != 0x80 {
+                    return None;
+                }
+                out = out << 6 | (cont & 0x3f);
+            }
+            Some(char::from_u32(out).ok_or(BadUnicode(out)))
+        }
+    }
+}
+pub mod flatten {
+    //! Flattens an [Iterator] returning [`Result<T, E>`](Result) or [`Option<T>`](Option)
+    //! into a *non-[FusedIterator](std::iter::FusedIterator)* over `T`
+
+    /// Flattens an [Iterator] returning [`Result<T, E>`](Result) or [`Option<T>`](Option)
+    /// into a *non-[FusedIterator](std::iter::FusedIterator)* over `T`
+    #[derive(Clone, Debug)]
+    pub struct Flatten<T, I: Iterator<Item = T>>(pub I);
+    impl<T, E, I: Iterator<Item = Result<T, E>>> Iterator for Flatten<Result<T, E>, I> {
+        type Item = T;
+        fn next(&mut self) -> Option<Self::Item> {
+            self.0.next()?.ok()
+        }
+    }
+    impl<T, I: Iterator<Item = Option<T>>> Iterator for Flatten<Option<T>, I> {
+        type Item = T;
+        fn next(&mut self) -> Option<Self::Item> {
+            self.0.next()?
+        }
+    }
+}

repline/src/lib.rs

@@ -0,0 +1,13 @@
+//! A small pseudo-multiline editing library
+
+mod editor;
+mod iter;
+mod raw;
+
+pub mod error;
+pub mod prebaked;
+pub mod repline;
+
+pub use error::Error;
+pub use prebaked::{read_and, Response};
+pub use repline::Repline;

repline/src/prebaked.rs

@@ -0,0 +1,56 @@
+//! Here's a menu I prepared earlier!
+//!
+//! Constructs a [Repline] and repeatedly runs the provided closure on the input strings,
+//! obeying the closure's [Response].
+
+use std::error::Error;
+
+use crate::{error::Error as RlError, repline::Repline};
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+/// Control codes for the [prebaked menu](read_and)
+pub enum Response {
+    /// Accept the line, and save it to history
+    Accept,
+    /// Reject the line, and clear the buffer
+    Deny,
+    /// End the loop
+    Break,
+    /// Gather more input and try again
+    Continue,
+}
+
+/// Implements a basic menu loop using an embedded [Repline].
+///
+/// Repeatedly runs the provided closure on the input strings,
+/// obeying the closure's [Response].
+///
+/// Captures and displays all user [Error]s.
+///
+/// # Keybinds
+/// - `Ctrl+C` exits the loop
+/// - `Ctrl+D` clears the input, but *runs the closure* with the old input
+pub fn read_and<F>(color: &str, begin: &str, again: &str, mut f: F) -> Result<(), RlError>
+where F: FnMut(&str) -> Result<Response, Box<dyn Error>> {
+    let mut rl = Repline::new(color, begin, again);
+    loop {
+        let line = match rl.read() {
+            Err(RlError::CtrlC(_)) => break,
+            Err(RlError::CtrlD(line)) => {
+                rl.deny();
+                line
+            }
+            Ok(line) => line,
+            Err(e) => Err(e)?,
+        };
+        print!("\x1b[G\x1b[J");
+        match f(&line) {
+            Ok(Response::Accept) => rl.accept(),
+            Ok(Response::Deny) => rl.deny(),
+            Ok(Response::Break) => break,
+            Ok(Response::Continue) => continue,
+            Err(e) => print!("\x1b[40G\x1b[A\x1bJ\x1b[91m{e}\x1b[0m\x1b[B"),
+        }
+    }
+    Ok(())
+}

repline/src/raw.rs

@@ -0,0 +1,21 @@
+//! Sets the terminal to [`raw`] mode for the duration of the returned object's lifetime.
+
+/// Sets the terminal to raw mode for the duration of the returned object's lifetime.
+pub fn raw() -> impl Drop {
+    Raw::default()
+}
+struct Raw();
+impl Default for Raw {
+    fn default() -> Self {
+        std::thread::yield_now();
+        crossterm::terminal::enable_raw_mode()
+            .expect("should be able to transition into raw mode");
+        Raw()
+    }
+}
+impl Drop for Raw {
+    fn drop(&mut self) {
+        crossterm::terminal::disable_raw_mode()
+            .expect("should be able to transition out of raw mode");
+    }
+}

repline/src/repline.rs

@@ -0,0 +1,175 @@
+//! Prompts the user, reads the lines. Not much more to it than that.
+//!
+//! This module is in charge of parsing keyboard input and interpreting it for the line editor.
+
+use crate::{editor::Editor, error::*, iter::*, raw::raw};
+use std::{
+    collections::VecDeque,
+    io::{stdout, Bytes, Read, Result, Write},
+};
+
+/// Prompts the user, reads the lines. Not much more to it than that.
+#[derive(Debug)]
+pub struct Repline<'a, R: Read> {
+    input: Chars<Flatten<Result<u8>, Bytes<R>>>,
+
+    history: VecDeque<String>, // previous lines
+    hindex: usize,             // current index into the history buffer
+
+    ed: Editor<'a>, // the current line buffer
+}
+
+impl<'a> Repline<'a, std::io::Stdin> {
+    pub fn new(color: &'a str, begin: &'a str, again: &'a str) -> Self {
+        Self::with_input(std::io::stdin(), color, begin, again)
+    }
+}
+
+impl<'a, R: Read> Repline<'a, R> {
+    /// Constructs a [Repline] with the given [Reader](Read), color, begin, and again prompts.
+    pub fn with_input(input: R, color: &'a str, begin: &'a str, again: &'a str) -> Self {
+        Self {
+            input: Chars(Flatten(input.bytes())),
+            history: Default::default(),
+            hindex: 0,
+            ed: Editor::new(color, begin, again),
+        }
+    }
+    /// Set the terminal prompt color
+    pub fn set_color(&mut self, color: &'a str) {
+        self.ed.color = color
+    }
+    /// Append line to history and clear it
+    pub fn accept(&mut self) {
+        self.history_append(self.ed.to_string());
+        self.ed.clear();
+        self.hindex = self.history.len();
+    }
+    /// Clear the line
+    pub fn deny(&mut self) {
+        self.ed.clear()
+    }
+    /// Reads in a line, and returns it for validation
+    pub fn read(&mut self) -> ReplResult<String> {
+        const INDENT: &str = "    ";
+        let mut stdout = stdout().lock();
+        let stdout = &mut stdout;
+        let _make_raw = raw();
+        // self.ed.begin_frame(stdout)?;
+        // self.ed.redraw_frame(stdout)?;
+        self.ed.print_head(stdout)?;
+        loop {
+            stdout.flush()?;
+            match self.input.next().ok_or(Error::EndOfInput)?? {
+                // Ctrl+C: End of Text. Immediately exits.
+                '\x03' => {
+                    drop(_make_raw);
+                    writeln!(stdout)?;
+                    return Err(Error::CtrlC(self.ed.to_string()));
+                }
+                // Ctrl+D: End of Transmission. Ends the current line.
+                '\x04' => {
+                    drop(_make_raw);
+                    writeln!(stdout)?;
+                    return Err(Error::CtrlD(self.ed.to_string()));
+                }
+                // Tab: extend line by 4 spaces
+                '\t' => {
+                    self.ed.extend(INDENT.chars(), stdout)?;
+                }
+                // ignore newlines, process line feeds. Not sure how cross-platform this is.
+                '\n' => {}
+                '\r' => {
+                    self.ed.push('\n', stdout)?;
+                    return Ok(self.ed.to_string());
+                }
+                // Ctrl+Backspace in my terminal
+                '\x17' => {
+                    self.ed.erase_word(stdout)?;
+                }
+                // Escape sequence
+                '\x1b' => self.escape(stdout)?,
+                // backspace
+                '\x08' | '\x7f' => {
+                    let ed = &mut self.ed;
+                    if ed.ends_with(INDENT.chars()) {
+                        for _ in 0..INDENT.len() {
+                            ed.pop(stdout)?;
+                        }
+                    } else {
+                        ed.pop(stdout)?;
+                    }
+                }
+                c if c.is_ascii_control() => {
+                    if cfg!(debug_assertions) {
+                        self.ed.extend(c.escape_debug(), stdout)?;
+                    }
+                }
+                c => {
+                    self.ed.push(c, stdout)?;
+                }
+            }
+        }
+    }
+    /// Handle ANSI Escape
+    fn escape<W: Write>(&mut self, w: &mut W) -> ReplResult<()> {
+        match self.input.next().ok_or(Error::EndOfInput)?? {
+            '[' => self.csi(w)?,
+            'O' => todo!("Process alternate character mode"),
+            other => self.ed.extend(other.escape_debug(), w)?,
+        }
+        Ok(())
+    }
+    /// Handle ANSI Control Sequence Introducer
+    fn csi<W: Write>(&mut self, w: &mut W) -> ReplResult<()> {
+        match self.input.next().ok_or(Error::EndOfInput)?? {
+            'A' => {
+                self.hindex = self.hindex.saturating_sub(1);
+                self.restore_history(w)?
+            }
+            'B' => {
+                self.hindex = self.hindex.saturating_add(1).min(self.history.len());
+                self.restore_history(w)?
+            }
+            'C' => self.ed.cursor_forward(1, w)?,
+            'D' => self.ed.cursor_back(1, w)?,
+            'H' => self.ed.home(w)?,
+            'F' => self.ed.end(w)?,
+            '3' => {
+                if let '~' = self.input.next().ok_or(Error::EndOfInput)?? {
+                    let _ = self.ed.delete(w);
+                }
+            }
+            other => {
+                if cfg!(debug_assertions) {
+                    self.ed.extend(other.escape_debug(), w)?;
+                }
+            }
+        }
+        Ok(())
+    }
+    /// Restores the currently selected history
+    fn restore_history<W: Write>(&mut self, w: &mut W) -> ReplResult<()> {
+        let Self { history, hindex, ed, .. } = self;
+        ed.undraw(w)?;
+        ed.clear();
+        ed.print_head(w)?;
+        if let Some(history) = history.get(*hindex) {
+            ed.extend(history.chars(), w)?
+        }
+        Ok(())
+    }
+
+    /// Append line to history
+    fn history_append(&mut self, mut buf: String) {
+        while buf.ends_with(char::is_whitespace) {
+            buf.pop();
+        }
+        if !self.history.contains(&buf) {
+            self.history.push_back(buf)
+        }
+        while self.history.len() > 20 {
+            self.history.pop_front();
+        }
+    }
+}