1
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Implement let assignment

This commit is contained in:
Jeff 2024-09-07 12:15:47 -04:00
parent 03d44434e2
commit 3ac15fe70b
7 changed files with 445 additions and 91 deletions

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@ -2,12 +2,13 @@ use std::fmt::{self, Debug, Display, Formatter};
use serde::{Deserialize, Serialize};
use crate::{Instruction, Span, Value};
use crate::{Identifier, Instruction, Span, Value};
#[derive(Clone, Eq, PartialEq, Serialize, Deserialize)]
#[derive(Debug, Clone, Eq, PartialEq, Serialize, Deserialize)]
pub struct Chunk {
code: Vec<(u8, Span)>,
constants: Vec<Value>,
identifiers: Vec<Identifier>,
}
impl Chunk {
@ -15,11 +16,20 @@ impl Chunk {
Self {
code: Vec::new(),
constants: Vec::new(),
identifiers: Vec::new(),
}
}
pub fn with_data(code: Vec<(u8, Span)>, constants: Vec<Value>) -> Self {
Self { code, constants }
pub fn with_data(
code: Vec<(u8, Span)>,
constants: Vec<Value>,
identifiers: Vec<Identifier>,
) -> Self {
Self {
code,
constants,
identifiers,
}
}
pub fn len(&self) -> usize {
@ -34,8 +44,10 @@ impl Chunk {
self.code.capacity()
}
pub fn read(&self, offset: usize) -> (u8, Span) {
self.code[offset]
pub fn read(&self, offset: usize) -> Result<&(u8, Span), ChunkError> {
self.code
.get(offset)
.ok_or(ChunkError::CodeIndextOfBounds(offset))
}
pub fn write(&mut self, instruction: u8, position: Span) {
@ -45,14 +57,14 @@ impl Chunk {
pub fn get_constant(&self, index: usize) -> Result<&Value, ChunkError> {
self.constants
.get(index)
.ok_or_else(|| ChunkError::ConstantIndexOutOfBounds(index))
.ok_or(ChunkError::ConstantIndexOutOfBounds(index))
}
pub fn push_constant(&mut self, value: Value) -> Result<u8, ChunkError> {
let starting_length = self.constants.len();
if starting_length + 1 > (u8::MAX as usize) {
Err(ChunkError::Overflow)
Err(ChunkError::ConstantOverflow)
} else {
self.constants.push(value);
@ -60,6 +72,24 @@ impl Chunk {
}
}
pub fn get_identifier(&self, index: usize) -> Result<&Identifier, ChunkError> {
self.identifiers
.get(index)
.ok_or(ChunkError::IdentifierIndexOutOfBounds(index))
}
pub fn push_identifier(&mut self, identifier: Identifier) -> Result<u8, ChunkError> {
let starting_length = self.constants.len();
if starting_length + 1 > (u8::MAX as usize) {
Err(ChunkError::IdentifierOverflow)
} else {
self.identifiers.push(identifier);
Ok(starting_length as u8)
}
}
pub fn clear(&mut self) {
self.code.clear();
self.constants.clear();
@ -112,14 +142,11 @@ impl Display for Chunk {
}
}
impl Debug for Chunk {
fn fmt(&self, f: &mut Formatter) -> fmt::Result {
write!(f, "{self}")
}
}
#[derive(Debug, Clone, Copy, PartialEq)]
pub enum ChunkError {
CodeIndextOfBounds(usize),
ConstantOverflow,
ConstantIndexOutOfBounds(usize),
Overflow,
IdentifierIndexOutOfBounds(usize),
IdentifierOverflow,
}

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@ -1,15 +1,16 @@
use crate::{vm::VmError, LexError, ParseError};
#[derive(Debug, PartialEq)]
pub enum DustError<'src> {
LexError {
Lex {
error: LexError,
source: &'src str,
},
ParseError {
Parse {
error: ParseError,
source: &'src str,
},
VmError {
Runtime {
error: VmError,
source: &'src str,
},

View File

@ -21,6 +21,7 @@ pub mod dust_error;
pub mod identifier;
pub mod lexer;
pub mod parser;
pub mod run;
pub mod token;
pub mod r#type;
pub mod value;
@ -31,8 +32,9 @@ pub use constructor::{ConstructError, Constructor};
pub use dust_error::DustError;
pub use identifier::Identifier;
pub use lexer::{LexError, Lexer};
pub use parser::{ParseError, Parser};
pub use parser::{parse, ParseError, Parser};
pub use r#type::{EnumType, FunctionType, RangeableType, StructType, Type, TypeConflict};
pub use run::run;
pub use token::{Token, TokenKind, TokenOwned};
pub use value::{Struct, Value, ValueError};
pub use vm::{Instruction, Vm};

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@ -1,20 +1,22 @@
use std::{
fmt::{self, Display, Formatter},
mem::{self, swap},
mem,
num::ParseIntError,
ptr::replace,
};
use crate::{
Chunk, ChunkError, Instruction, LexError, Lexer, Span, Token, TokenKind, TokenOwned, Value,
Chunk, ChunkError, DustError, Identifier, Instruction, LexError, Lexer, Span, Token, TokenKind,
TokenOwned, Value,
};
pub fn parse(source: &str) -> Result<Chunk, ParseError> {
pub fn parse(source: &str) -> Result<Chunk, DustError> {
let lexer = Lexer::new(source);
let mut parser = Parser::new(lexer);
while !parser.is_eof() {
parser.parse(Precedence::None)?;
parser
.parse_statement()
.map_err(|error| DustError::Parse { error, source })?;
}
Ok(parser.chunk)
@ -35,6 +37,8 @@ impl<'src> Parser<'src> {
let (current_token, current_position) =
lexer.next_token().unwrap_or((Token::Eof, Span(0, 0)));
log::trace!("Starting parser with token {current_token} at {current_position}");
Parser {
lexer,
chunk: Chunk::new(),
@ -60,7 +64,17 @@ impl<'src> Parser<'src> {
Ok(())
}
fn consume(&mut self, expected: TokenKind) -> Result<(), ParseError> {
fn allow(&mut self, allowed: TokenKind) -> Result<bool, ParseError> {
if self.current_token.kind() == allowed {
self.advance()?;
Ok(true)
} else {
Ok(false)
}
}
fn expect(&mut self, expected: TokenKind) -> Result<(), ParseError> {
if self.current_token.kind() == expected {
self.advance()
} else {
@ -97,6 +111,17 @@ impl<'src> Parser<'src> {
Ok(())
}
fn parse_float(&mut self) -> Result<(), ParseError> {
if let Token::Float(text) = self.previous_token {
let float = text.parse::<f64>().unwrap();
let value = Value::float(float);
self.emit_constant(value)?;
}
Ok(())
}
fn parse_integer(&mut self) -> Result<(), ParseError> {
if let Token::Integer(text) = self.previous_token {
let integer = text.parse::<i64>().unwrap();
@ -108,25 +133,36 @@ impl<'src> Parser<'src> {
Ok(())
}
fn parse_string(&mut self) -> Result<(), ParseError> {
if let Token::String(text) = self.previous_token {
let value = Value::string(text);
self.emit_constant(value)?;
}
Ok(())
}
fn parse_grouped(&mut self) -> Result<(), ParseError> {
self.parse_expression()?;
self.consume(TokenKind::RightParenthesis)
self.expect(TokenKind::RightParenthesis)
}
fn parse_unary(&mut self) -> Result<(), ParseError> {
let operator_position = self.previous_position;
let byte = match self.previous_token.kind() {
TokenKind::Minus => Instruction::Negate as u8,
_ => {
return Err(ParseError::ExpectedTokenMultiple {
expected: vec![TokenKind::Minus],
found: self.previous_token.to_owned(),
position: self.previous_position,
position: operator_position,
})
}
};
self.parse_expression()?;
self.emit_byte(byte, self.previous_position);
self.emit_byte(byte, operator_position);
Ok(())
}
@ -162,10 +198,73 @@ impl<'src> Parser<'src> {
Ok(())
}
fn parse_variable(&mut self) -> Result<(), ParseError> {
todo!()
}
fn parse_identifier(&mut self) -> Result<u8, ParseError> {
if let Token::Identifier(text) = self.current_token {
self.advance()?;
let identifier = Identifier::new(text);
let identifier_index = self.chunk.push_identifier(identifier)?;
Ok(identifier_index)
} else {
Err(ParseError::ExpectedToken {
expected: TokenKind::Identifier,
found: self.current_token.to_owned(),
position: self.current_position,
})
}
}
fn parse_expression(&mut self) -> Result<(), ParseError> {
self.parse(Precedence::None)
}
fn parse_statement(&mut self) -> Result<(), ParseError> {
match self.current_token {
Token::Let => self.parse_let_assignment()?,
_ => self.parse_expression_statement()?,
}
Ok(())
}
fn parse_expression_statement(&mut self) -> Result<(), ParseError> {
let start = self.current_position.0;
self.parse_expression()?;
if self.allow(TokenKind::Semicolon)? {
let end = self.previous_position.1;
self.emit_byte(Instruction::Pop as u8, Span(start, end));
}
Ok(())
}
fn parse_let_assignment(&mut self) -> Result<(), ParseError> {
self.expect(TokenKind::Let)?;
let position = self.current_position;
let identifier_index = self.parse_identifier()?;
self.expect(TokenKind::Equal)?;
self.parse_expression()?;
self.expect(TokenKind::Semicolon)?;
self.define_variable(identifier_index, position)
}
fn define_variable(&mut self, identifier_index: u8, position: Span) -> Result<(), ParseError> {
self.emit_byte(Instruction::DefineGlobal as u8, position);
self.emit_byte(identifier_index, position);
Ok(())
}
fn parse(&mut self, precedence: Precedence) -> Result<(), ParseError> {
self.advance()?;
@ -183,7 +282,7 @@ impl<'src> Parser<'src> {
});
}
while precedence <= ParseRule::from(&self.current_token.kind()).precedence {
while precedence < ParseRule::from(&self.current_token.kind()).precedence {
self.advance()?;
let infix_rule = ParseRule::from(&self.previous_token.kind()).infix;
@ -266,20 +365,32 @@ impl From<&TokenKind> for ParseRule<'_> {
infix: None,
precedence: Precedence::None,
},
TokenKind::Identifier => todo!(),
TokenKind::Identifier => ParseRule {
prefix: Some(Parser::parse_variable),
infix: None,
precedence: Precedence::None,
},
TokenKind::Boolean => ParseRule {
prefix: Some(Parser::parse_boolean),
infix: None,
precedence: Precedence::None,
},
TokenKind::Character => todo!(),
TokenKind::Float => todo!(),
TokenKind::Float => ParseRule {
prefix: Some(Parser::parse_float),
infix: None,
precedence: Precedence::None,
},
TokenKind::Integer => ParseRule {
prefix: Some(Parser::parse_integer),
infix: None,
precedence: Precedence::None,
},
TokenKind::String => todo!(),
TokenKind::String => ParseRule {
prefix: Some(Parser::parse_string),
infix: None,
precedence: Precedence::None,
},
TokenKind::Async => todo!(),
TokenKind::Bool => todo!(),
TokenKind::Break => todo!(),
@ -334,7 +445,11 @@ impl From<&TokenKind> for ParseRule<'_> {
precedence: Precedence::None,
},
TokenKind::RightSquareBrace => todo!(),
TokenKind::Semicolon => todo!(),
TokenKind::Semicolon => ParseRule {
prefix: None,
infix: None,
precedence: Precedence::None,
},
TokenKind::Star => ParseRule {
prefix: None,
infix: Some(Parser::parse_binary),
@ -395,6 +510,41 @@ impl From<ChunkError> for ParseError {
mod tests {
use super::*;
#[test]
fn let_statement() {
let source = "let x = 42;";
let test_chunk = parse(source);
assert_eq!(
test_chunk,
Ok(Chunk::with_data(
vec![
(Instruction::Constant as u8, Span(8, 10)),
(0, Span(8, 10)),
(Instruction::DefineGlobal as u8, Span(4, 5)),
(0, Span(4, 5))
],
vec![Value::integer(42)],
vec![Identifier::new("x")]
))
);
}
#[test]
fn string() {
let source = "\"Hello, World!\"";
let test_chunk = parse(source);
assert_eq!(
test_chunk,
Ok(Chunk::with_data(
vec![(Instruction::Constant as u8, Span(0, 15)), (0, Span(0, 15))],
vec![Value::string("Hello, World!")],
vec![]
))
);
}
#[test]
fn integer() {
let source = "42";
@ -404,7 +554,8 @@ mod tests {
test_chunk,
Ok(Chunk::with_data(
vec![(Instruction::Constant as u8, Span(0, 2)), (0, Span(0, 2))],
vec![Value::integer(42)]
vec![Value::integer(42)],
vec![]
))
);
}
@ -418,15 +569,14 @@ mod tests {
test_chunk,
Ok(Chunk::with_data(
vec![(Instruction::Constant as u8, Span(0, 4)), (0, Span(0, 4))],
vec![Value::boolean(true)]
vec![Value::boolean(true)],
vec![]
))
);
}
#[test]
fn grouping() {
env_logger::builder().is_test(true).try_init().unwrap();
let source = "(42 + 42) * 2";
let test_chunk = parse(source);
@ -439,11 +589,31 @@ mod tests {
(Instruction::Constant as u8, Span(6, 8)),
(1, Span(6, 8)),
(Instruction::Add as u8, Span(4, 5)),
(Instruction::Constant as u8, Span(11, 12)),
(0, Span(11, 12)),
(Instruction::Multiply as u8, Span(9, 10)),
(Instruction::Constant as u8, Span(12, 13)),
(2, Span(12, 13)),
(Instruction::Multiply as u8, Span(10, 11)),
],
vec![Value::integer(42), Value::integer(42), Value::integer(2)]
vec![Value::integer(42), Value::integer(42), Value::integer(2)],
vec![]
))
);
}
#[test]
fn negation() {
let source = "-(42)";
let test_chunk = parse(source);
assert_eq!(
test_chunk,
Ok(Chunk::with_data(
vec![
(Instruction::Constant as u8, Span(2, 4)),
(0, Span(2, 4)),
(Instruction::Negate as u8, Span(0, 1)),
],
vec![Value::integer(42)],
vec![]
))
);
}
@ -463,7 +633,8 @@ mod tests {
(1, Span(5, 7)),
(Instruction::Add as u8, Span(3, 4)),
],
vec![Value::integer(42), Value::integer(42)]
vec![Value::integer(42), Value::integer(42)],
vec![]
))
);
}
@ -483,7 +654,8 @@ mod tests {
(1, Span(5, 7)),
(Instruction::Subtract as u8, Span(3, 4)),
],
vec![Value::integer(42), Value::integer(42)]
vec![Value::integer(42), Value::integer(42)],
vec![]
))
);
}
@ -503,7 +675,8 @@ mod tests {
(1, Span(5, 7)),
(Instruction::Multiply as u8, Span(3, 4)),
],
vec![Value::integer(42), Value::integer(42)]
vec![Value::integer(42), Value::integer(42)],
vec![]
))
);
}
@ -523,7 +696,8 @@ mod tests {
(1, Span(5, 7)),
(Instruction::Divide as u8, Span(3, 4)),
],
vec![Value::integer(42), Value::integer(42)]
vec![Value::integer(42), Value::integer(42)],
vec![]
))
);
}

31
dust-lang/src/run.rs Normal file
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@ -0,0 +1,31 @@
use crate::{parse, DustError, Value, Vm};
pub fn run(source: &str) -> Result<Option<Value>, DustError> {
let chunk = parse(source)?;
let mut vm = Vm::new(chunk);
vm.interpret()
.map_err(|error| DustError::Runtime { error, source })
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn integer() {
let source = "42";
let result = run(source);
assert_eq!(result, Ok(Some(Value::integer(42))));
}
#[test]
fn addition() {
let source = "21 + 21";
let result = run(source);
assert_eq!(result, Ok(Some(Value::integer(42))));
}
}

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@ -1,12 +1,15 @@
use std::collections::HashMap;
use serde::{Deserialize, Serialize};
use crate::{Chunk, ChunkError, Span, Value, ValueError};
use crate::{Chunk, ChunkError, Identifier, Span, Value, ValueError};
#[derive(Debug, Clone, Eq, PartialEq)]
pub struct Vm {
chunk: Chunk,
ip: usize,
stack: Vec<Value>,
globals: HashMap<Identifier, Value>,
}
impl Vm {
@ -17,18 +20,18 @@ impl Vm {
chunk,
ip: 0,
stack: Vec::with_capacity(Self::STACK_SIZE),
globals: HashMap::new(),
}
}
pub fn interpret(&mut self) -> Result<Option<Value>, VmError> {
loop {
let (byte, position) = self.read();
while let Ok((byte, position)) = self.read().copied() {
let instruction = Instruction::from_byte(byte)
.ok_or_else(|| VmError::InvalidInstruction(byte, position))?;
match instruction {
Instruction::Constant => {
let (index, _) = self.read();
let (index, position) = self.read().copied()?;
let value = self.read_constant(index as usize)?;
self.stack.push(value);
@ -38,6 +41,16 @@ impl Vm {
return Ok(Some(value));
}
Instruction::Pop => {
self.pop()?;
}
Instruction::DefineGlobal => {
let (index, _) = self.read().copied()?;
let identifier = self.chunk.get_identifier(index as usize)?.clone();
let value = self.pop()?;
self.globals.insert(identifier, value);
}
// Unary
Instruction::Negate => {
@ -45,45 +58,104 @@ impl Vm {
self.stack.push(negated);
}
Instruction::Not => {
let not = self.pop()?.not()?;
self.stack.push(not);
}
// Binary
Instruction::Add => {
let b = self.pop()?;
let a = self.pop()?;
let sum = a.add(&b)?;
let right = self.pop()?;
let left = self.pop()?;
let sum = left.add(&right)?;
self.stack.push(sum);
}
Instruction::Subtract => {
let b = self.pop()?;
let a = self.pop()?;
let difference = a.subtract(&b)?;
let right = self.pop()?;
let left = self.pop()?;
let difference = left.subtract(&right)?;
self.stack.push(difference);
}
Instruction::Multiply => {
let b = self.pop()?;
let a = self.pop()?;
let product = a.multiply(&b)?;
let right = self.pop()?;
let left = self.pop()?;
let product = left.multiply(&right)?;
self.stack.push(product);
}
Instruction::Divide => {
let b = self.pop()?;
let a = self.pop()?;
let quotient = a.divide(&b)?;
let right = self.pop()?;
let left = self.pop()?;
let quotient = left.divide(&right)?;
self.stack.push(quotient);
}
Instruction::Greater => {
let right = self.pop()?;
let left = self.pop()?;
let greater = left.greater_than(&right)?;
self.stack.push(greater);
}
Instruction::Less => {
let right = self.pop()?;
let left = self.pop()?;
let less = left.less_than(&right)?;
self.stack.push(less);
}
Instruction::GreaterEqual => {
let right = self.pop()?;
let left = self.pop()?;
let greater_equal = left.greater_than_or_equal(&right)?;
self.stack.push(greater_equal);
}
Instruction::LessEqual => {
let right = self.pop()?;
let left = self.pop()?;
let less_equal = left.less_than_or_equal(&right)?;
self.stack.push(less_equal);
}
Instruction::Equal => {
let right = self.pop()?;
let left = self.pop()?;
let equal = left.equal(&right)?;
self.stack.push(equal);
}
Instruction::NotEqual => {
let right = self.pop()?;
let left = self.pop()?;
let not_equal = left.not_equal(&right)?;
self.stack.push(not_equal);
}
Instruction::And => {
let right = self.pop()?;
let left = self.pop()?;
let and = left.and(&right)?;
self.stack.push(and);
}
Instruction::Or => {
let right = self.pop()?;
let left = self.pop()?;
let or = left.or(&right)?;
self.stack.push(or);
}
}
}
Ok(self.stack.pop())
}
pub fn push(&mut self, value: Value) -> Result<(), VmError> {
fn push(&mut self, value: Value) -> Result<(), VmError> {
if self.stack.len() == Self::STACK_SIZE {
Err(VmError::StackOverflow)
} else {
@ -93,7 +165,7 @@ impl Vm {
}
}
pub fn pop(&mut self) -> Result<Value, VmError> {
fn pop(&mut self) -> Result<Value, VmError> {
if let Some(value) = self.stack.pop() {
Ok(value)
} else {
@ -101,13 +173,15 @@ impl Vm {
}
}
pub fn read(&mut self) -> (u8, Span) {
fn read(&mut self) -> Result<&(u8, Span), VmError> {
let current = self.chunk.read(self.ip)?;
self.ip += 1;
self.chunk.read(self.ip - 1)
Ok(current)
}
pub fn read_constant(&self, index: usize) -> Result<Value, VmError> {
fn read_constant(&self, index: usize) -> Result<Value, VmError> {
Ok(self.chunk.get_constant(index)?.clone())
}
}
@ -138,32 +212,49 @@ impl From<ValueError> for VmError {
pub enum Instruction {
Constant = 0,
Return = 1,
Pop = 2,
DefineGlobal = 3,
// Unary
Negate = 2,
Negate = 4,
Not = 5,
// Binary
Add = 3,
Subtract = 4,
Multiply = 5,
Divide = 6,
Add = 6,
Subtract = 7,
Multiply = 8,
Divide = 9,
Greater = 10,
Less = 11,
GreaterEqual = 12,
LessEqual = 13,
Equal = 14,
NotEqual = 15,
And = 16,
Or = 17,
}
impl Instruction {
pub fn from_byte(byte: u8) -> Option<Self> {
match byte {
0 => Some(Self::Constant),
1 => Some(Self::Return),
// Unary
2 => Some(Self::Negate),
// Binary
3 => Some(Self::Add),
4 => Some(Self::Subtract),
5 => Some(Self::Multiply),
6 => Some(Self::Divide),
0 => Some(Instruction::Constant),
1 => Some(Instruction::Return),
2 => Some(Instruction::Pop),
3 => Some(Instruction::DefineGlobal),
4 => Some(Instruction::Negate),
5 => Some(Instruction::Not),
6 => Some(Instruction::Add),
7 => Some(Instruction::Subtract),
8 => Some(Instruction::Multiply),
9 => Some(Instruction::Divide),
10 => Some(Instruction::Greater),
11 => Some(Instruction::Less),
12 => Some(Instruction::GreaterEqual),
13 => Some(Instruction::LessEqual),
14 => Some(Instruction::Equal),
15 => Some(Instruction::NotEqual),
16 => Some(Instruction::And),
17 => Some(Instruction::Or),
_ => None,
}
}
@ -171,24 +262,40 @@ impl Instruction {
pub fn disassemble(&self, chunk: &Chunk, offset: usize) -> String {
match self {
Instruction::Constant => {
let (index, _) = chunk.read(offset + 1);
let (index, _) = chunk.read(offset + 1).unwrap();
let value_display = chunk
.get_constant(index as usize)
.get_constant(*index as usize)
.map(|value| value.to_string())
.unwrap_or_else(|error| format!("{:?}", error));
format!("{offset:04} CONSTANT {index} {value_display}")
}
Instruction::Return => format!("{offset:04} RETURN"),
Instruction::Pop => format!("{offset:04} POP"),
Instruction::DefineGlobal => {
let (index, _) = chunk.read(offset + 1).unwrap();
let identifier = chunk.get_identifier(*index as usize).unwrap();
format!("{offset:04} DEFINE_GLOBAL {identifier}")
}
// Unary
Instruction::Negate => format!("{offset:04} NEGATE"),
Instruction::Not => format!("{offset:04} NOT"),
// Binary
Instruction::Add => format!("{offset:04} ADD"),
Instruction::Subtract => format!("{offset:04} SUBTRACT"),
Instruction::Multiply => format!("{offset:04} MULTIPLY"),
Instruction::Divide => format!("{offset:04} DIVIDE"),
Instruction::Greater => format!("{offset:04} GREATER"),
Instruction::Less => format!("{offset:04} LESS"),
Instruction::GreaterEqual => format!("{offset:04} GREATER_EQUAL"),
Instruction::LessEqual => format!("{offset:04} LESS_EQUAL"),
Instruction::Equal => format!("{offset:04} EQUAL"),
Instruction::NotEqual => format!("{offset:04} NOT_EQUAL"),
Instruction::And => format!("{offset:04} AND"),
Instruction::Or => format!("{offset:04} OR"),
}
}
}

View File

@ -1,6 +1,7 @@
use std::fs::read_to_string;
use clap::Parser;
use dust_lang::{parse, run};
#[derive(Parser)]
struct Cli {
@ -36,9 +37,20 @@ fn main() {
}
fn parse_and_display_errors(source: &str) {
todo!()
match parse(source) {
Ok(chunk) => println!("{chunk}"),
Err(error) => {
eprintln!("{:?}", error);
}
}
}
fn run_and_display_errors(source: &str) {
todo!()
match run(source) {
Ok(Some(value)) => println!("{}", value),
Ok(_) => {}
Err(error) => {
eprintln!("{:?}", error);
}
}
}