⭐ star: add a primitive REPL

This turned out a few new bugs in the VM

lunar_wave_cli/src/main.rs

@@ -1,6 +1,9 @@
 // cargo run -- --script lunar_wave_vm/test_vectors/fizz_buzz.lua
 
-use std::io::Read;
+use std::io::{
+	Read,
+	Write,
+};
 
 use lunar_wave_vm as lwvm;
 
@@ -36,9 +39,8 @@ fn lunar_wave (args: Vec <String>) -> Result <Vec <lwvm::Value>, lwvm::StepError
 			"-" => {
 				let mut buf = vec! [];
 				std::io::stdin ().read_to_end (&mut buf).unwrap ();
-				let bc = lwvm::ensure_bytecode (buf);
+				let bc = lwvm::ensure_bytecode (buf).unwrap ();
-				let mut rdr = std::io::Cursor::new (bc);
+				chunk = Some (lwvm::parse_chunk (&bc).unwrap ());
-				chunk = Some (lwvm::parse_chunk (&mut rdr).unwrap ());
 				
 				lua_args = vec! ["-".to_string ()];
 			},
@@ -49,8 +51,7 @@ fn lunar_wave (args: Vec <String>) -> Result <Vec <lwvm::Value>, lwvm::StepError
 				}
 				else if chunk.is_none () {
 					let bc = lwvm::compile_bytecode_from_file (x);
-					let mut rdr = std::io::Cursor::new (bc);
+					chunk = Some (lwvm::parse_chunk (&bc).unwrap ());
-					chunk = Some (lwvm::parse_chunk (&mut rdr).unwrap ());
 					
 					lua_args = vec! [x.to_string ()];
 				}
@@ -61,24 +62,55 @@ fn lunar_wave (args: Vec <String>) -> Result <Vec <lwvm::Value>, lwvm::StepError
 		}
 	}
 	
-	let chunk = chunk.unwrap ();
+	match chunk {
-	
+		Some (chunk) => debugger (DebuggerParams {
-	if list_bytecode {
+			breakpoints,
-		dbg! (&chunk);
+			chunk,
+			list_bytecode,
+			lua_args,
+		}),
+		None => repl (ReplParams {
+			list_bytecode,
+			lua_args,
+		}),
+	}
 }
 
-	let upvalues = lwvm::State::upvalues_from_args (lua_args.into_iter ());
+struct DebuggerParams {
+	breakpoints: Vec <lwvm::Breakpoint>,
+	chunk: lwvm::Chunk,
+	list_bytecode: bool,
+	lua_args: Vec <String>,
+}
 
-	let mut vm = lwvm::State::new (chunk, upvalues);
+struct ReplParams {
+	list_bytecode: bool,
+	lua_args: Vec <String>,
+}
+
+/// The interpreter mode, which has optional debugging abilities
+/// sort of like a cut-down gdb.
+
+fn debugger (params: DebuggerParams) -> Result <Vec <lwvm::Value>, lwvm::StepError> 
+{
+	if params.list_bytecode {
+		dbg! (&params.chunk);
+	}
+	
+	let upvalues = lwvm::State::upvalues_from_args (params.lua_args.into_iter ());
+	
+	let mut vm = lwvm::State::new (params.chunk, upvalues);
 	if std::env::var("LWVM_DEBUG").is_ok() {
 		vm.debug_print = true;
 	}
 	
+	// Variables for interactive debugging
+	
 	let mut in_break = false;
 	let mut last_input = String::new ();
 	
 	loop {
-		if in_break || breakpoints.iter ().any (|bp| vm.at_breakpoint (bp)) {
+		if in_break || params.breakpoints.iter ().any (|bp| vm.at_breakpoint (bp)) {
 			in_break = true;
 			dbg! (&vm.stack);
 			
@@ -122,3 +154,52 @@ fn lunar_wave (args: Vec <String>) -> Result <Vec <lwvm::Value>, lwvm::StepError
 	}
 }
 
+/// A REPL that's sort of like the PUC Lua or LuaJIT REPL, 
+/// but with fewer features.
+/// It still have to cheat and run `luac5.4` as a subprocess.
+
+fn repl (params: ReplParams) -> Result <Vec <lwvm::Value>, lwvm::StepError> 
+{
+	let upvalues = lwvm::State::upvalues_from_args (params.lua_args.into_iter ());
+	
+	let mut vm = lwvm::State::new (lwvm::Chunk::default (), upvalues);
+	
+	println! ("Lunar Wave 0.1.0-modified  Copyright (C) 2023 ReactorScram (implements Lua 5.4  Copyright (C) 1994-2022 Lua.org, PUC-Rio");
+	
+	loop {
+		{
+			let mut stdout = std::io::stdout ().lock ();
+			stdout.write_all (b"> ").unwrap ();
+			stdout.flush ().unwrap ();
+		}
+		
+		let mut input = Default::default ();
+		std::io::stdin ().read_line (&mut input).unwrap ();
+		if input.is_empty () {
+			println! ();
+			return Ok (vec! []);
+		}
+		
+		let bytecode = match lwvm::compile_bytecode (input.into_bytes ()) {
+			Ok (x) => x,
+			Err (e) => {
+				eprintln! ("Compile error from luac subprocess:");
+				eprintln! ("{}", e);
+				continue;
+			},
+		};
+		let chunk = lwvm::parse_chunk (&bytecode).unwrap ();
+		
+		if params.list_bytecode {
+			dbg! (&chunk);
+		}
+		
+		vm.set_chunk (chunk);
+		match vm.execute () {
+			Ok (x) => if ! x.is_empty () {
+				println! ("{x:?}")
+			},
+			Err (e) => println! ("{e:?}"),
+		}
+	}
+}

lunar_wave_vm/src/instruction.rs

@@ -5,6 +5,7 @@ pub enum Instruction {
 	
 	Call (u8, u8, u8),
 	Closure (u8, u32),
+	Concat (u8, u8),
 	
 	Div (u8, u8, u8),
 	
@@ -84,7 +85,7 @@ pub enum Instruction {
 	
 	SetList (u8, u8, u8, bool),
 	
-	SetTabUp (u8, u8, u8),
+	SetTabUp (u8, u8, u8, bool),
 	
 	Sub (u8, u8, u8),
 	

lunar_wave_vm/src/lib.rs

@@ -7,7 +7,9 @@ pub use loader::compile_bytecode_from_file as compile_bytecode_from_file;
 pub use loader::compile_bytecode as compile_bytecode;
 pub use loader::ensure_bytecode as ensure_bytecode;
 pub use loader::parse_chunk as parse_chunk;
+pub use loader::parse_chunk_from_reader as parse_chunk_from_reader;
 pub use state::Breakpoint as Breakpoint;
+pub use state::Chunk as Chunk;
 pub use state::State as State;
 pub use state::StepError as StepError;
 pub use state::StepOutput as StepOutput;

lunar_wave_vm/src/loader.rs

@@ -34,7 +34,7 @@ pub fn compile_bytecode_from_file (path: &str) -> Vec <u8> {
 /// 
 /// `source` is a Vec because we move it to a worker thread
 
-pub fn compile_bytecode (source: Vec <u8>) -> Vec <u8> {
+pub fn compile_bytecode (source: Vec <u8>) -> Result <Vec <u8>, String> {
 	use std::{
 		io::Write,
 		process::{
@@ -48,6 +48,7 @@ pub fn compile_bytecode (source: Vec <u8>) -> Vec <u8> {
 	.arg ("-")  // Standard output
 	.arg ("-")  // Input from standard input
 	.stdin (Stdio::piped ())
+	.stderr (Stdio::piped ())
 	.stdout (Stdio::piped ())
 	.spawn ()
 	.expect ("failed to execute `luac5.4`. Is Lua installed?");
@@ -61,17 +62,23 @@ pub fn compile_bytecode (source: Vec <u8>) -> Vec <u8> {
 	.wait_with_output ()
 	.expect ("failed to wait on child");
 	
-	output.stdout.as_slice ().to_vec ()
+	if output.status.success () && output.status.code () == Some (0) 
+	{
+		Ok (output.stdout)
+	}
+	else {
+		Err (String::from_utf8 (output.stderr).unwrap ())
+	}
 }
 
 /// Checks whether the input is already bytecode, or is possibly
 /// Lua source code. If it's source code, compiles and returns bytecode.
 /// If it's bytecode, just returns the input.
 
-pub fn ensure_bytecode (buffer: Vec <u8>) -> Vec <u8> {
+pub fn ensure_bytecode (buffer: Vec <u8>) -> Result <Vec <u8>, String> {
 	let bytecode_header = &[0x1b, 0x4c, 0x75, 0x61, 0x54, 0x00, 0x19, 0x93];
 	if buffer.starts_with (bytecode_header) {
-		return buffer;
+		return Ok (buffer);
 	}
 	
 	compile_bytecode (buffer)
@@ -116,7 +123,7 @@ pub fn parse_inst (buf: [u8; 4]) -> Option <Inst>
 		0x0c => Inst::GetTable (a, b, c),
 		0x0d => Inst::GetI (a, b, c),
 		0x0e => Inst::GetField (a, b, c),
-		0x0f => Inst::SetTabUp (a, b, c),
+		0x0f => Inst::SetTabUp (a, b, c, k),
 		0x11 => Inst::SetI (a, b, c, k),
 		0x12 => Inst::SetField (a, b, c, k),
 		0x13 => Inst::NewTable (a),
@@ -133,6 +140,7 @@ pub fn parse_inst (buf: [u8; 4]) -> Option <Inst>
 		0x31 => Inst::UnM (a, b),
 		0x33 => Inst::Not (a, b),
 		0x34 => Inst::Len (a, b),
+		0x35 => Inst::Concat (a, b),
 		0x3c => Inst::EqK (a, b, k),
 		0x3d => Inst::EqI (a, i_sb (buf)?, k),
 		0x38 => Inst::Jmp (s_j),
@@ -333,8 +341,12 @@ pub fn parse_block <R: Read> (rdr: &mut R, blocks: &mut Vec <Block>)
 	Some (())
 }
 
+pub fn parse_chunk (buf: &[u8]) -> Option <Chunk> {
+	let mut rdr = std::io::Cursor::new (buf);
+	parse_chunk_from_reader (&mut rdr)
+}
 
-pub fn parse_chunk <R: Read> (rdr: &mut R) -> Option <Chunk> {
+pub fn parse_chunk_from_reader <R: Read> (rdr: &mut R) -> Option <Chunk> {
 	// Discard 32 bytes from the start of the file.
 	// This is magic number, version number, etc.
 	
@@ -352,11 +364,6 @@ pub fn parse_chunk <R: Read> (rdr: &mut R) -> Option <Chunk> {
 	})
 }
 
-pub fn parse_chunk_from_bytes (b: &[u8]) -> Option <Chunk> {
-	let mut rdr = std::io::Cursor::new (b);
-	parse_chunk (&mut rdr)
-}
-
 #[cfg (test)]
 mod tests {
 	#[test]
@@ -447,8 +454,7 @@ mod tests {
 		}
 		
 		if false {
-			let mut rdr = std::io::Cursor::new (bytecode.clone ());
+			let file = crate::loader::parse_chunk (bytecode).unwrap ();
-			let file = crate::loader::parse_chunk (&mut rdr).unwrap ();
 			
 			assert_eq! (file.blocks.len (), 5);
 		}

lunar_wave_vm/src/state.rs

@@ -20,12 +20,12 @@ pub struct Block {
 	pub upvalues: Vec <Upvalue>,
 }
 
-#[derive (Clone, Debug)]
+#[derive (Clone, Debug, Default)]
 pub struct Chunk {
 	pub blocks: Vec <Block>,
 }
 
-#[derive (Clone, Debug)]
+#[derive (Clone, Debug, Default)]
 pub struct StackFrame {
 	// i32 makes it a little easier to implement jumps
 	// Starts at 0 right after OP_CALL
@@ -148,11 +148,7 @@ impl State {
 			registers: vec! [Value::Nil; 256],
 			top: 0,
 			stack: vec! [
-				StackFrame {
+				StackFrame::default (),
-					program_counter: 0,
-					block_idx: 0,
-					register_offset: 0,
-				},
 			],
 			debug_print: false,
 			step_count: 0,
@@ -386,6 +382,9 @@ impl State {
 					upvalues: new_upvalues,
 				});
 			},
+			Instruction::Concat (a, b) => {
+				unimplemented! ("OP_CONCAT")
+			},
 			Instruction::Div (a, b, c) => {
 				let v_b = self.reg (b);
 				let v_c = self.reg (c);
@@ -760,7 +759,22 @@ impl State {
 					dst.insert_int (i64::from (c + i), src.clone ());
 				}
 			},
-			Instruction::SetTabUp (_a, _b, _c) => unimplemented! (),
+			Instruction::SetTabUp (a, b, c, k_flag) => {
+				let a = usize::try_from (a).unwrap ();
+				let b = usize::try_from (b).unwrap ();
+				
+				let value = if k_flag {
+					&k [usize::from (c)]
+				}
+				else {
+					self.reg (c)
+				}
+				.clone ();
+				
+				let table = self.upvalues.get_mut (a).unwrap ().as_table ().unwrap ();
+				let key = k.get (b).unwrap ().as_str ().expect ("SetTabUp K[B] must be a string");
+				table.borrow_mut ().insert_str (key, value);
+			},
 			Instruction::Sub (a, b, c) => {
 				let v_b = self.reg (b);
 				let v_c = self.reg (c);
@@ -886,15 +900,11 @@ impl State {
 		Ok (None)
 	}
 	
-	pub fn execute_chunk (&mut self, breakpoints: &[Breakpoint]) 
+	pub fn execute (&mut self) 
 	-> Result <Vec <Value>, StepError> {
 		let max_iters = 2000;
 		
 		for _ in 0..max_iters {
-			if breakpoints.iter ().any (|bp| self.at_breakpoint (bp)) {
-				dbg! (&self);
-			}
-			
 			match self.step ()? {
 				None => (),
 				Some (StepOutput::ChunkReturned (x)) => return Ok (x),
@@ -904,4 +914,9 @@ impl State {
 		dbg! (self);
 		panic! ("Hit max iterations before block returned");
 	}
+	
+	pub fn set_chunk (&mut self, chunk: Chunk) {
+		self.stack = vec! [Default::default ()];
+		self.chunk = chunk;
+	}
 }

lunar_wave_vm/src/tests.rs

@@ -25,14 +25,14 @@ fn calculate_hash<T: Hash>(t: &T) -> u64 {
 fn run_chunk (args: &[&str], chunk: Chunk) -> Vec <Value> {
 	let upvalues = State::upvalues_from_args (args.into_iter ().map (|s| s.to_string ()));
 	let mut vm = State::new (chunk, upvalues);
-	vm.execute_chunk (&[]).unwrap ()
+	vm.execute ().unwrap ()
 }
 
 /// Takes arguments and Lua bytecode, loads it, runs it,
 /// and return the output
 
 fn run_bytecode (args: &[&str], bc: &[u8]) -> Vec <Value> {
-	let chunk = loader::parse_chunk_from_bytes (&bc).unwrap ();
+	let chunk = loader::parse_chunk (&bc).unwrap ();
 	run_chunk (args, chunk)
 }
 
@@ -42,7 +42,7 @@ fn run_bytecode (args: &[&str], bc: &[u8]) -> Vec <Value> {
 /// and returns the output
 
 fn run_source (args: &[&str], s: &str) -> Vec <Value> {
-	let bc = loader::compile_bytecode (s.as_bytes ().to_vec ());
+	let bc = loader::compile_bytecode (s.as_bytes ().to_vec ()).unwrap ();
 	run_bytecode (args, &bc)
 }
 
@@ -120,7 +120,7 @@ fn bools () {
 		
 		let upvalues = State::upvalues_from_args (arg.into_iter ().map (|s| s.to_string ()));
 		let mut vm = State::new (chunk.clone (), upvalues);
-		let actual = vm.execute_chunk (&[]).unwrap ();
+		let actual = vm.execute ().unwrap ();
 		assert_eq! (actual, expected);
 	}
 }
@@ -128,8 +128,8 @@ fn bools () {
 #[test]
 fn closure () {
 	let source = include_bytes! ("../test_vectors/closure.lua");
-	let bytecode = &crate::loader::compile_bytecode (source.to_vec ());
+	let bytecode = &crate::loader::compile_bytecode (source.to_vec ()).unwrap ();
-	let chunk = crate::loader::parse_chunk_from_bytes (bytecode).unwrap ();
+	let chunk = crate::loader::parse_chunk (bytecode).unwrap ();
 	
 	assert_eq! (run_chunk (&["_exe_name"], chunk), vec! [Value::from (23i64)]);
 }
@@ -176,7 +176,7 @@ fn floats () {
 		let expected: Vec <Value> = expected;
 		let upvalues = State::upvalues_from_args (arg.into_iter ().map (|s| s.to_string ()));
 		let mut vm = State::new (chunk.clone (), upvalues);
-		let actual = vm.execute_chunk (&[]).unwrap ();
+		let actual = vm.execute ().unwrap ();
 		
 		assert_eq! (actual, expected);
 	}
@@ -185,8 +185,8 @@ fn floats () {
 #[test]
 fn fma () {
 	let source = include_bytes! ("../test_vectors/fma.lua");
-	let bytecode = &crate::loader::compile_bytecode (source.to_vec ());
+	let bytecode = &crate::loader::compile_bytecode (source.to_vec ()).unwrap ();
-	let chunk = crate::loader::parse_chunk_from_bytes (bytecode).unwrap ();
+	let chunk = crate::loader::parse_chunk (bytecode).unwrap ();
 	assert_eq! (chunk.blocks.len (), 5);
 	
 	assert_eq! (chunk.blocks [3].upvalues.len (), 2);
@@ -194,12 +194,43 @@ fn fma () {
 	let arg = vec! ["_exe_name"];
 	let upvalues = State::upvalues_from_args (arg.into_iter ().map (|s| s.to_string ()));
 	let mut vm = State::new (chunk, upvalues);
-	let actual = vm.execute_chunk (&[]).unwrap ();
+	let actual = vm.execute ().unwrap ();
 	let expected = vec! [Value::from (122)];
 	
 	assert_eq! (actual, expected);
 }
 
+#[test]
+fn function_calls () {
+	let upvalues = crate::State::upvalues_from_args (vec! ["_exe_name".to_string ()].into_iter ());
+	
+	let mut vm = crate::State::new (crate::Chunk::default (), upvalues);
+	
+	{
+		let bc = crate::compile_bytecode (b"print (x ())".to_vec ()).unwrap ();
+		let chunk = crate::parse_chunk (&bc).unwrap ();
+		
+		vm.set_chunk (chunk);
+		vm.execute ().unwrap ();
+	}
+	
+	{
+		let bc = crate::compile_bytecode (b"x = function () return 5 end".to_vec ()).unwrap ();
+		let chunk = crate::parse_chunk (&bc).unwrap ();
+		
+		vm.set_chunk (chunk);
+		vm.execute ().unwrap ();
+	}
+	
+	{
+		let bc = crate::compile_bytecode (b"print (x ())".to_vec ()).unwrap ();
+		let chunk = crate::parse_chunk (&bc).unwrap ();
+		
+		vm.set_chunk (chunk);
+		vm.execute ().unwrap ();
+	}
+}
+
 #[test]
 fn heap () {
 	use std::{
@@ -265,7 +296,7 @@ fn is_93 () {
 	assert_ne! (calculate_hash (&Value::from ("94")), calculate_hash (&Value::from ("93")));
 	assert_ne! (Value::Nil, Value::from ("93"));
 	
-	let src = r#"
+	let src = br#"
 	if arg [1] == "93" then
 		print "it's 93"
 		return 0
@@ -275,8 +306,8 @@ fn is_93 () {
 	end
 	"#;
 	
-	let bc = loader::compile_bytecode (src.as_bytes ().to_vec ());
+	let bc = loader::compile_bytecode (src.to_vec ()).unwrap ();
-	let chunk = loader::parse_chunk_from_bytes (&bc).unwrap ();
+	let chunk = loader::parse_chunk (&bc).unwrap ();
 	
 	assert_eq! (chunk.blocks [0].instructions [3], Inst::EqK (0, 1, false));
 	
@@ -359,12 +390,12 @@ fn tables_2 () {
 fn tailcall () {
 	use crate::instruction::Instruction;
 	
-	let src = r#"
+	let src = br#"
 	return tonumber ("5")
 	"#;
 	
-	let bc = loader::compile_bytecode (src.as_bytes ().to_vec ());
+	let bc = loader::compile_bytecode (src.to_vec ()).unwrap ();
-	let chunk = loader::parse_chunk_from_bytes (&bc).unwrap ();
+	let chunk = loader::parse_chunk (&bc).unwrap ();
 	
 	assert_eq! (chunk.blocks [0].instructions [3], Instruction::TailCall (0, 2, 1, false));
 	

lunar_wave_vm/tests/embedding.rs

@@ -19,9 +19,8 @@ fn embedding () {
 		1
 	}
 	
-	let bytecode = lwvm::compile_bytecode (src.to_vec ());
+	let bc = lwvm::compile_bytecode (src.to_vec ()).unwrap ();
-	let mut rdr = std::io::Cursor::new (bytecode);
+	let chunk = lwvm::parse_chunk (&bc).unwrap ();
-	let chunk = lwvm::parse_chunk (&mut rdr).unwrap ();
 	
 	let host_lib = [
 		("add", Value::RsFunc (host_add)),
@@ -36,7 +35,7 @@ fn embedding () {
 	];
 	
 	let mut vm = State::new (chunk, upvalues);
-	let output = vm.execute_chunk (&vec! []).unwrap ();
+	let output = vm.execute ().unwrap ();
 	
 	assert_eq! (output, vec! [Value::from (2019)]);
 }