Implement a REPL (#83)

Cargo.lock

@@ -335,6 +335,17 @@ version = "0.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2da6da31387c7e4ef160ffab6d5e7f00c42626fe39aea70a7b0f1773f7dd6c1b"
 
+[[package]]
+name = "clipboard-win"
+version = "4.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7191c27c2357d9b7ef96baac1773290d4ca63b24205b82a3fd8a0637afcf0362"
+dependencies = [
+ "error-code",
+ "str-buf",
+ "winapi",
+]
+
 [[package]]
 name = "colorchoice"
 version = "1.0.0"
@@ -519,6 +530,12 @@ dependencies = [
  "cfg-if",
 ]
 
+[[package]]
+name = "endian-type"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c34f04666d835ff5d62e058c3995147c06f42fe86ff053337632bca83e42702d"
+
 [[package]]
 name = "env_logger"
 version = "0.10.0"
@@ -568,12 +585,33 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "error-code"
+version = "2.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "64f18991e7bf11e7ffee451b5318b5c1a73c52d0d0ada6e5a3017c8c1ced6a21"
+dependencies = [
+ "libc",
+ "str-buf",
+]
+
 [[package]]
 name = "fastrand"
 version = "2.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6999dc1837253364c2ebb0704ba97994bd874e8f195d665c50b7548f6ea92764"
 
+[[package]]
+name = "fd-lock"
+version = "3.0.13"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ef033ed5e9bad94e55838ca0ca906db0e043f517adda0c8b79c7a8c66c93c1b5"
+dependencies = [
+ "cfg-if",
+ "rustix",
+ "windows-sys 0.48.0",
+]
+
 [[package]]
 name = "flate2"
 version = "1.0.26"
@@ -745,6 +783,15 @@ version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "443144c8cdadd93ebf52ddb4056d257f5b52c04d3c804e657d19eb73fc33668b"
 
+[[package]]
+name = "home"
+version = "0.5.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5444c27eef6923071f7ebcc33e3444508466a76f7a2b93da00ed6e19f30c1ddb"
+dependencies = [
+ "windows-sys 0.48.0",
+]
+
 [[package]]
 name = "http"
 version = "0.2.9"
@@ -1012,6 +1059,7 @@ dependencies = [
  "rbx_xml",
  "regex",
  "reqwest",
+ "rustyline",
  "serde",
  "serde_json",
  "serde_yaml",
@@ -1111,6 +1159,27 @@ dependencies = [
  "pkg-config",
 ]
 
+[[package]]
+name = "nibble_vec"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "77a5d83df9f36fe23f0c3648c6bbb8b0298bb5f1939c8f2704431371f4b84d43"
+dependencies = [
+ "smallvec",
+]
+
+[[package]]
+name = "nix"
+version = "0.26.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bfdda3d196821d6af13126e40375cdf7da646a96114af134d5f417a9a1dc8e1a"
+dependencies = [
+ "bitflags 1.3.2",
+ "cfg-if",
+ "libc",
+ "static_assertions",
+]
+
 [[package]]
 name = "num-traits"
 version = "0.2.16"
@@ -1314,6 +1383,16 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "radix_trie"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c069c179fcdc6a2fe24d8d18305cf085fdbd4f922c041943e203685d6a1c58fd"
+dependencies = [
+ "endian-type",
+ "nibble_vec",
+]
+
 [[package]]
 name = "rand"
 version = "0.8.5"
@@ -1674,6 +1753,29 @@ dependencies = [
  "untrusted",
 ]
 
+[[package]]
+name = "rustyline"
+version = "12.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "994eca4bca05c87e86e15d90fc7a91d1be64b4482b38cb2d27474568fe7c9db9"
+dependencies = [
+ "bitflags 2.3.3",
+ "cfg-if",
+ "clipboard-win",
+ "fd-lock",
+ "home",
+ "libc",
+ "log",
+ "memchr",
+ "nix",
+ "radix_trie",
+ "scopeguard",
+ "unicode-segmentation",
+ "unicode-width",
+ "utf8parse",
+ "winapi",
+]
+
 [[package]]
 name = "ryu"
 version = "1.0.15"
@@ -1939,6 +2041,12 @@ version = "0.1.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "213701ba3370744dcd1a12960caa4843b3d68b4d1c0a5d575e0d65b2ee9d16c0"
 
+[[package]]
+name = "str-buf"
+version = "1.0.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9e08d8363704e6c71fc928674353e6b7c23dcea9d82d7012c8faf2a3a025f8d0"
+
 [[package]]
 name = "strsim"
 version = "0.10.0"
@@ -2289,6 +2397,12 @@ dependencies = [
  "tinyvec",
 ]
 
+[[package]]
+name = "unicode-segmentation"
+version = "1.10.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1dd624098567895118886609431a7c3b8f516e41d30e0643f03d94592a147e36"
+
 [[package]]
 name = "unicode-width"
 version = "0.1.10"

Cargo.toml

@@ -119,6 +119,7 @@ regex = { optional = true, version = "1.7", default-features = false, features =
     "std",
     "unicode-perl",
 ] }
+rustyline = "12.0.0"
 
 ### ROBLOX
 

src/cli/mod.rs

@@ -10,6 +10,7 @@ use tokio::{
 };
 
 pub(crate) mod gen;
+pub(crate) mod repl;
 pub(crate) mod setup;
 pub(crate) mod utils;
 
@@ -146,12 +147,14 @@ impl Cli {
             if generate_file_requested {
                 return Ok(ExitCode::SUCCESS);
             }
+
             // HACK: We know that we didn't get any arguments here but since
             // script_path is optional clap will not error on its own, to fix
-            // we will duplicate the cli command and make arguments required,
+            // we will duplicate the CLI command and fetch the version of
-            // which will then fail and print out the normal help message
+            // lune to display
-            let cmd = Cli::command();
+            let exit_code_status = repl::show_interface(Cli::command()).await;
-            cmd.arg_required_else_help(true).get_matches();
+
+            return exit_code_status;
         }
         // Figure out if we should read from stdin or from a file,
         // reading from stdin is marked by passing a single "-"

src/cli/repl.rs

@@ -0,0 +1,101 @@
+use std::{path::PathBuf, process::ExitCode};
+
+use anyhow::{Error, Result};
+use clap::Command;
+use directories::UserDirs;
+use lune::Lune;
+use rustyline::{error::ReadlineError, DefaultEditor};
+
+#[derive(PartialEq)]
+enum PromptState {
+    Regular,
+    Continuation,
+}
+
+// Isn't dependency injection plain awesome?!
+pub async fn show_interface(cmd: Command) -> Result<ExitCode> {
+    let lune_version = cmd.get_version();
+
+    // The version is mandatory and will always exist
+    println!("Lune v{}", lune_version.unwrap());
+
+    let lune_instance = Lune::new();
+
+    let mut repl = DefaultEditor::new()?;
+    let history_file_path: &PathBuf = &UserDirs::new()
+        .ok_or(Error::msg("cannot find user home directory"))?
+        .home_dir()
+        .join(".lune_history");
+
+    if !history_file_path.exists() {
+        std::fs::write(&history_file_path, String::new())?;
+    }
+
+    repl.load_history(history_file_path)?;
+
+    let mut interrupt_counter = 0u32;
+    let mut prompt_state: PromptState = PromptState::Regular;
+    let mut source_code = String::new();
+
+    loop {
+        let prompt = match prompt_state {
+            PromptState::Regular => "> ",
+            PromptState::Continuation => ">> ",
+        };
+
+        match repl.readline(prompt) {
+            Ok(code) => {
+                if prompt_state == PromptState::Continuation {
+                    source_code.push_str(&code);
+                } else if prompt_state == PromptState::Regular {
+                    source_code = code.clone();
+                }
+
+                repl.add_history_entry(code.as_str())?;
+
+                // If source code eval was requested, we reset the counter
+                interrupt_counter = 0;
+            }
+
+            Err(ReadlineError::Interrupted) => {
+                // HACK: We actually want the user to do ^C twice to exit,
+                // but the user would need to ^C one more time even after
+                // the check passes, so we check for 1 instead of 2
+                if interrupt_counter != 1 {
+                    println!("Interrupt: ^C again to exit");
+
+                    // Increment the counter
+                    interrupt_counter += 1;
+                } else {
+                    repl.save_history(history_file_path)?;
+                    break;
+                }
+            }
+            Err(ReadlineError::Eof) => {
+                repl.save_history(history_file_path)?;
+                break;
+            }
+            Err(err) => {
+                eprintln!("REPL ERROR: {err}");
+                return Ok(ExitCode::FAILURE);
+            }
+        };
+
+        let eval_result = lune_instance.run("REPL", source_code.clone()).await;
+
+        match eval_result {
+            Ok(_) => prompt_state = PromptState::Regular,
+
+            Err(err) => {
+                if err.is_incomplete_input() {
+                    prompt_state = PromptState::Continuation;
+                    source_code.push('\n')
+                } else {
+                    eprintln!("{err}");
+                }
+            }
+        };
+    }
+
+    Ok(ExitCode::SUCCESS)
+}