Improve CLI

- Remove unused flags
- Show more helpful error messages

src/interpreter.rs

@@ -5,6 +5,7 @@ use crate::{
     ast::{Ast, BinOpType, BlockScope, Expression, FunDecl, If, Statement, UnOpType},
     astoptimizer::{AstOptimizer, SimpleAstOptimizer},
     lexer::lex,
+    nice_panic,
     parser::parse,
     stringstore::{Sid, StringStore},
 };
@@ -13,18 +14,25 @@ use crate::{
 pub enum RuntimeError {
     #[error("Invalid error Index: {}", 0.to_string())]
     InvalidArrayIndex(Value),
+
     #[error("Variable used but not declared: {0}")]
     VarUsedNotDeclared(String),
+
     #[error("Can't index into non-array variable: {0}")]
     TryingToIndexNonArray(String),
+
     #[error("Invalid value type for unary operation: {}", 0.to_string())]
     UnOpInvalidType(Value),
+
     #[error("Incompatible binary operations. Operands don't match: {} {}", 0.to_string(), 1.to_string())]
     BinOpIncompatibleTypes(Value, Value),
+
     #[error("Array access out of bounds: Accessed {0}, size is {1}")]
     ArrayOutOfBounds(usize, usize),
+
     #[error("Division by zero")]
     DivideByZero,
+
     #[error("Invalid number of arguments for function {0}. Expected {1}, got {2}")]
     InvalidNumberOfArgs(String, usize, usize),
 }
@@ -83,14 +91,24 @@ impl Interpreter {
     }
 
     pub fn run_str(&mut self, code: &str) {
-        let tokens = lex(code).unwrap();
+        let tokens = match lex(code) {
+            Ok(tokens) => tokens,
+            Err(e) => nice_panic!("Lexing error: {}", e),
+        };
+
         if self.print_tokens {
             println!("Tokens: {:?}", tokens);
         }
 
-        let ast = parse(tokens).unwrap();
+        let ast = match parse(tokens) {
+            Ok(ast) => ast,
+            Err(e) => nice_panic!("Parsing error: {}", e),
+        };
 
-        self.run_ast(ast).unwrap();
+        match self.run_ast(ast) {
+            Ok(_) => (),
+            Err(e) => nice_panic!("Runtime error: {}", e),
+        }
     }
 
     pub fn run_ast(&mut self, mut ast: Ast) -> Result<(), RuntimeError> {
@@ -137,15 +155,13 @@ impl Interpreter {
                     self.vartable.push(rhs);
                 }
 
-                Statement::Block(block) => {
+                Statement::Block(block) => match self.run_block(block)? {
-                    match self.run_block(block)? {
+                    BlockExit::Return(val) => {
-                        BlockExit::Return(val) => {
+                        self.vartable.truncate(framepointer);
-                            self.vartable.truncate(framepointer);
+                        return Ok(BlockExit::Return(val));
-                            return Ok(BlockExit::Return(val));
-                        }
-                        _ => ()
                     }
-                }
+                    _ => (),
+                },
 
                 Statement::Loop(looop) => {
                     // loop runs as long condition != 0
@@ -225,7 +241,10 @@ impl Interpreter {
 
                 // All of the arg expressions must be resolved before pushing the vars on the stack,
                 // otherwise the stack positions are incorrect while resolving
-                let args = args.iter().map(|arg| self.resolve_expr(arg)).collect::<Vec<_>>();
+                let args = args
+                    .iter()
+                    .map(|arg| self.resolve_expr(arg))
+                    .collect::<Vec<_>>();
                 for arg in args {
                     self.vartable.push(arg?);
                 }
@@ -234,8 +253,16 @@ impl Interpreter {
                 let expected_num_args = self.funtable.get(*fun_stackpos).unwrap().argnames.len();
 
                 if expected_num_args != args_len {
-                    let fun_name = self.stringstore.lookup(*fun_name).cloned().unwrap_or("<unknown>".to_string());
+                    let fun_name = self
-                    return Err(RuntimeError::InvalidNumberOfArgs(fun_name, expected_num_args, args_len));
+                        .stringstore
+                        .lookup(*fun_name)
+                        .cloned()
+                        .unwrap_or("<unknown>".to_string());
+                    return Err(RuntimeError::InvalidNumberOfArgs(
+                        fun_name,
+                        expected_num_args,
+                        args_len,
+                    ));
                 }
 
                 match self.run_block_fp_offset(
@@ -414,7 +441,12 @@ impl Interpreter {
         match val {
             Value::I64(val) => format!("{}", val),
             Value::Array(val) => format!("{:?}", val.borrow()),
-            Value::String(text) => format!("{}", self.stringstore.lookup(*text).unwrap_or(&"<invalid string>".to_string())),
+            Value::String(text) => format!(
+                "{}",
+                self.stringstore
+                    .lookup(*text)
+                    .unwrap_or(&"<invalid string>".to_string())
+            ),
             Value::Void => format!("void"),
         }
     }

src/main.rs

@@ -1,18 +1,12 @@
-use std::{
+use std::{env::args, fs, process::exit};
-    env::args,
-    fs,
-    // io::{stdin, stdout, Write},
-    process::exit,
-};
 
-use nek_lang::interpreter::Interpreter;
+use nek_lang::{interpreter::Interpreter, nice_panic};
 
 #[derive(Debug, Default)]
 struct CliConfig {
     print_tokens: bool,
     print_ast: bool,
     no_optimizations: bool,
-    // interactive: bool,
     file: Option<String>,
 }
 
@@ -25,10 +19,11 @@ fn main() {
             "--token" | "-t" => conf.print_tokens = true,
             "--ast" | "-a" => conf.print_ast = true,
             "--no-opt" | "-n" => conf.no_optimizations = true,
-            // "--interactive" | "-i" => conf.interactive = true,
             "--help" | "-h" => print_help(),
-            file if conf.file.is_none() => conf.file = Some(file.to_string()),
+            file if !arg.starts_with("-") && conf.file.is_none() => {
-            _ => panic!("Invalid argument: '{}'", arg),
+                conf.file = Some(file.to_string())
+            }
+            _ => nice_panic!("Error: Invalid argument '{}'", arg),
         }
     }
 
@@ -39,32 +34,15 @@ fn main() {
     interpreter.optimize_ast = !conf.no_optimizations;
 
     if let Some(file) = &conf.file {
-        let code = fs::read_to_string(file).expect(&format!("File not found: '{}'", file));
+        let code = match fs::read_to_string(file) {
+            Ok(code) => code,
+            Err(_) => nice_panic!("Error: Could not read file '{}'", file),
+        };
         interpreter.run_str(&code);
+    } else {
+        println!("Error: No file given\n");
+        print_help();
     }
-
-    // TODO: The interactive prompt is currently broken due to the precalculated stack positions.
-    // For this to still work, there needs to be a way to keep the stack in the interpreter after
-    // runing once. Also somehow the stringstore and var stack from the last parsing stages would
-    // need to be reused for the parser to work correctly
-
-    // if conf.interactive || conf.file.is_none() {
-    //     let mut code = String::new();
-
-    //     loop {
-    //         print!(">> ");
-    //         stdout().flush().unwrap();
-
-    //         code.clear();
-    //         stdin().read_line(&mut code).unwrap();
-
-    //         if code.trim() == "exit" {
-    //             break;
-    //         }
-
-    //         interpreter.run_str(&code);
-    //     }
-    // }
 }
 
 fn print_help() {
@@ -73,7 +51,6 @@ fn print_help() {
     println!("-t, --token        Print the lexed tokens");
     println!("-a, --ast          Print the abstract syntax tree");
     println!("-n, --no-opt       Disable the AST optimizations");
-    // println!("-i, --interactive  Interactive mode");
     println!("-h, --help         Show this help screen");
     exit(0);
 }

src/util.rs

@@ -1,3 +1,23 @@
+/// Exit the program with error code 1 and format-print the given text on stderr. This pretty much
+/// works like panic, but doesn't show the additional information that panic adds. Those can be 
+/// interesting for debugging, but don't look that great when building a release executable for an
+/// end user.
+#[macro_export]
+macro_rules! nice_panic {
+    ($fmt:expr) => {
+        {
+            eprintln!($fmt);
+            std::process::exit(1);
+        }
+    };
+    ($fmt:expr, $($arg:tt)*) => {
+        {
+            eprintln!($fmt, $($arg)*);
+            std::process::exit(1);
+        }
+    };
+}
+
 /// The PutBackIter allows for items to be put back back and to be peeked. Putting an item back
 /// will cause it to be the next item returned by `next`. Peeking an item will get a reference to
 /// the next item in the iterator without removing it.
@@ -14,7 +34,7 @@ impl<T> PutBackIter<T>
 where
     T: Iterator,
 {
-    /// Make the given iterator putbackable, wrapping it in the PutBackIter type. This effectively 
+    /// Make the given iterator putbackable, wrapping it in the PutBackIter type. This effectively
     /// adds the `peek` and `putback` functions.
     pub fn new(iter: T) -> Self {
         Self {
@@ -31,7 +51,7 @@ where
         self.putback_stack.push(it);
     }
 
-    /// Peek the next item, getting a reference to it without removing it from the iterator. This 
+    /// Peek the next item, getting a reference to it without removing it from the iterator. This
     /// also includes items that were previsouly put back and not yet removed.
     pub fn peek(&mut self) -> Option<&T::Item> {
         if self.putback_stack.is_empty() {
@@ -58,7 +78,7 @@ where
 }
 
 pub trait PutBackableExt {
-    /// Make the iterator putbackable, wrapping it in the PutBackIter type. This effectively 
+    /// Make the iterator putbackable, wrapping it in the PutBackIter type. This effectively
     /// adds the `peek` and `putback` functions.
     fn putbackable(self) -> PutBackIter<Self>
     where
@@ -117,7 +137,7 @@ mod tests {
         let it4 = pb_iter.next();
         assert_eq!(it4, iter.next());
 
-        // Put one value back and check if `next` works as expected, returning the just put back 
+        // Put one value back and check if `next` works as expected, returning the just put back
         // item
         pb_iter.putback(it0.unwrap());
         assert_eq!(pb_iter.next(), it0);