Improved bin/repl functionality

complexpr-bin/Cargo.toml

@@ -7,10 +7,14 @@ edition = "2021"
 
 [dependencies]
 complexpr = { path = "../complexpr" }
-rustyline = "10.0.0"
 backtrace = "0.3.66"
-rustyline-derive = "0.7.0"
+rustyline = { version = "10.0.0", optional = true }
+rustyline-derive = { version = "0.7.0", optional = true }
 
 [[bin]]
 name = "complexpr"
 path = "src/main.rs"
+
+[features]
+default = ["repl"]
+repl = ["dep:rustyline", "dep:rustyline-derive"]

complexpr-bin/src/helper.rs

@@ -1,3 +1,4 @@
+#![cfg(feature = "repl")]
 use std::borrow::Cow;
 
 use complexpr::env::EnvRef;
@@ -100,6 +101,10 @@ impl Highlighter for CxprHelper {
     fn highlight_char(&self, line: &str, _: usize) -> bool {
         !line.is_empty()
     }
+
+    fn highlight_hint<'h>(&self, hint: &'h str) -> Cow<'h, str> {
+        Cow::Owned(format!("\x1b[90m{}\x1b[0m", hint))
+    }
 }
 
 fn validate_brackets(input: &str) -> ValidationResult {

complexpr-bin/src/main.rs

@@ -1,16 +1,10 @@
-use std::{fs, panic::{self, PanicInfo}};
+use std::{fs, panic::{self, PanicInfo}, process::ExitCode};
 
 use backtrace::Backtrace;
-use complexpr::{env::Environment, interpreter::interpret, value::Value, stdlib};
-use rustyline::{self, error::ReadlineError, Config, CompletionType, EditMode, hint::HistoryHinter, validate::MatchingBracketValidator, Editor};
+use complexpr::{interpreter::interpret};
 
 mod helper;
-use helper::CxprHelper;
-
-const C_RESET: &str = "\x1b[0m";
-const C_BLUE: &str = "\x1b[94m";
-const C_RED: &str = "\x1b[91m";
-const PROMPT: &str = "\x1b[94m>> \x1b[0m";
+mod repl;
 
 fn panic_hook(info: &PanicInfo) {
     eprintln!("{:?}", Backtrace::new());
@@ -28,60 +22,36 @@ fn panic_hook(info: &PanicInfo) {
     }
 }
 
-fn main() -> Result<(), Box<dyn std::error::Error>> {
+fn main() -> ExitCode {
     panic::set_hook(Box::new(panic_hook));
     let args: Vec<String> = std::env::args().collect();
     if args.len() == 2 {
         let fname = &args[1];
-        let src = fs::read_to_string(fname)?;
+        let src = match fs::read_to_string(fname) {
+            Ok(src) => src,
+            Err(e) => {
+                eprintln!("Error reading file: {}", e);
+                return ExitCode::from(2);
+            }
+        };
         let res = interpret(&src, Some(fname.into()), None, false);
         if let Err(e) = res {
             eprintln!("Error: {}", e);
+            return ExitCode::from(1);
         }
     } else {
-        repl()?;
-    }
-    Ok(())
-}
-
-fn repl() -> Result<(), Box<dyn std::error::Error>> {
-    let config = Config::builder()
-        .history_ignore_space(true)
-        .completion_type(CompletionType::List)
-        .edit_mode(EditMode::Emacs)
-        .build();
-    let env = Environment::new().wrap();
-    let h = CxprHelper {
-        hinter: HistoryHinter {},
-        colored_prompt: PROMPT.to_owned(),
-        validator: MatchingBracketValidator::new(),
-        env: env.clone(),
-    };
-    let mut rl = Editor::with_config(config)?;
-    rl.set_helper(Some(h));
-    println!("Press {}Ctrl+D{} to exit.", C_BLUE, C_RESET);
-    stdlib::load(&mut env.borrow_mut());
-    stdlib::io::load(&mut env.borrow_mut());
-    stdlib::iter::load(&mut env.borrow_mut());
-    stdlib::math::load(&mut env.borrow_mut());
-    loop {
-        let readline = rl.readline(">> ");
-        match readline {
-            Ok(line) => {
-                let result = interpret(&line, None, Some(env.clone()), true);
-                match result {
-                    Ok(value) => {
-                        if value != Value::Nil {
-                            println!("{}", value.repr());
-                        }
-                        env.borrow_mut().declare("_".into(), value);
-                    }
-                    Err(e) => eprintln!("{}Error: {}{}", C_RED, C_RESET, e)
-                }
+        #[cfg(feature = "repl")]
+        {
+            if let Err(e) = repl::repl() {
+                eprintln!("Error: {}", e);
+                return ExitCode::from(4)
             }
-            Err(ReadlineError::Eof) => break,
-            Err(_) => (),
+        }
+        #[cfg(not(feature = "repl"))]
+        {
+            eprintln!("Expected a file to execute. To use complexpr in repl mode, enable the 'repl' feature (enabled by default).");
+            return ExitCode::from(3)
         }
     }
-    Ok(())
+    ExitCode::SUCCESS
 }

complexpr-bin/src/repl.rs

@@ -0,0 +1,69 @@
+#![cfg(feature = "repl")]
+
+use rustyline::{self, error::ReadlineError, Config, CompletionType, EditMode, hint::HistoryHinter, validate::MatchingBracketValidator, Editor};
+use complexpr::{env::Environment, interpreter::interpret, value::Value, stdlib};
+
+use crate::helper::CxprHelper;
+
+const C_RESET: &str = "\x1b[0m";
+const C_BLUE: &str = "\x1b[94m";
+const C_RED: &str = "\x1b[91m";
+const PROMPT: &str = "\x1b[94m>> \x1b[0m";
+
+pub fn repl() -> Result<(), Box<dyn std::error::Error>> {
+    let config = Config::builder()
+        .history_ignore_space(true)
+        .completion_type(CompletionType::List)
+        .edit_mode(EditMode::Emacs)
+        .build();
+
+    let env = Environment::new().wrap();
+
+    let h = CxprHelper {
+        hinter: HistoryHinter {},
+        colored_prompt: PROMPT.to_owned(),
+        validator: MatchingBracketValidator::new(),
+        env: env.clone(),
+    };
+
+    let histfile = std::env::var("COMPLEXPR_HISTORY").ok();
+
+    let mut rl = Editor::with_config(config)?;
+    rl.set_helper(Some(h));
+    if let Some(hf) = &histfile {
+        rl.load_history(hf)?;
+    }
+
+    println!("Press {}Ctrl+D{} to exit.", C_BLUE, C_RESET);
+
+    stdlib::load(&mut env.borrow_mut());
+    stdlib::io::load(&mut env.borrow_mut());
+    stdlib::iter::load(&mut env.borrow_mut());
+    stdlib::math::load(&mut env.borrow_mut());
+
+    loop {
+        let readline = rl.readline(">> ");
+        match readline {
+            Ok(line) => {
+                rl.add_history_entry(&line);
+                let result = interpret(&line, None, Some(env.clone()), true);
+                match result {
+                    Ok(value) => {
+                        if value != Value::Nil {
+                            println!("{}", value.repr());
+                        }
+                        env.borrow_mut().declare("_".into(), value);
+                    }
+                    Err(e) => eprintln!("{}Error: {}{}", C_RED, C_RESET, e)
+                }
+            }
+            Err(ReadlineError::Eof) => break,
+            Err(_) => (),
+        }
+    }
+
+    if let Some(hf) = &histfile {
+        rl.save_history(hf)?
+    }
+    Ok(())
+}