AST: Init

src/ast/astnode.rs

@@ -0,0 +1,214 @@
+use std::fmt::{Debug, Display};
+
+use crate::lexer::token;
+
+pub enum ASTNode {
+	BinaryExpr(BinaryExpr),
+	GroupingExpr(GroupingExpr),
+	Literal(Literal),
+	UnaryExpr(UnaryExpr),
+}
+
+impl From<BinaryExpr> for ASTNode {
+	fn from(b: BinaryExpr) -> Self {
+		ASTNode::BinaryExpr(b)
+	}
+}
+
+impl From<GroupingExpr> for ASTNode {
+	fn from(g: GroupingExpr) -> Self {
+		Self::GroupingExpr(g)
+	}
+}
+
+impl From<Literal> for ASTNode {
+	fn from(l: Literal) -> Self {
+		Self::Literal(l)
+	}
+}
+
+impl From<UnaryExpr> for ASTNode {
+	fn from(u: UnaryExpr) -> Self {
+		Self::UnaryExpr(u)
+	}
+}
+
+impl Debug for ASTNode {
+	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+		match self {
+			Self::BinaryExpr(b) => b.fmt(f),
+			Self::GroupingExpr(g) => g.fmt(f),
+			Self::Literal(l) => l.fmt(f),
+			Self::UnaryExpr(u) => u.fmt(f),
+		}
+	}
+}
+
+pub enum UnaryOperator {
+	Minus,
+	Bang,
+}
+
+impl TryFrom<token::TokenType> for UnaryOperator {
+	type Error = EnumConvertError;
+
+	fn try_from(value: token::TokenType) -> Result<Self, Self::Error> {
+		Ok(match value {
+			token::TokenType::Bang => Self::Bang,
+			token::TokenType::Minus => Self::Minus,
+			_ => return Err(EnumConvertError),
+		})
+	}
+}
+
+impl Display for UnaryOperator {
+	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+		write!(
+			f,
+			"{}",
+			match *self {
+				UnaryOperator::Minus => "-",
+				UnaryOperator::Bang => "!",
+			}
+		)
+	}
+}
+
+pub enum Operator {
+	Bang,
+	BangEqual,
+	Equal,
+	EqualEqual,
+	Greater,
+	GreaterEqual,
+	Less,
+	LessEqual,
+}
+
+#[derive(Debug)]
+pub struct EnumConvertError;
+impl std::fmt::Display for EnumConvertError {
+	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+		write!(f, "Couldn't convert between enums")
+	}
+}
+
+impl std::error::Error for EnumConvertError {}
+
+impl TryFrom<token::TokenType> for Operator {
+	type Error = EnumConvertError;
+
+	fn try_from(value: token::TokenType) -> Result<Self, Self::Error> {
+		Ok(match value {
+			token::TokenType::Bang => Self::Bang,
+			token::TokenType::BangEqual => Self::BangEqual,
+			token::TokenType::Equal => Self::Equal,
+			token::TokenType::EqualEqual => Self::EqualEqual,
+			token::TokenType::Greater => Self::Greater,
+			token::TokenType::GreaterEqual => Self::GreaterEqual,
+			token::TokenType::Less => Self::Less,
+			token::TokenType::LessEqual => Self::LessEqual,
+
+			_ => return Err(EnumConvertError),
+		})
+	}
+}
+
+impl Display for Operator {
+	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+		write!(
+			f,
+			"{}",
+			match *self {
+				Operator::Bang => "!",
+				Operator::Less => "<",
+				Operator::Equal => "=",
+				Operator::Greater => ">",
+				Operator::BangEqual => "!=",
+				Operator::LessEqual => "<=",
+				Operator::EqualEqual => "==",
+				Operator::GreaterEqual => ">=",
+			}
+		)
+	}
+}
+
+#[derive(Debug)]
+pub enum Literal {
+	String(String),
+	Int(i64),
+	Float(f64),
+	Bool(bool),
+}
+
+pub struct BinaryExpr {
+	left: Box<ASTNode>,
+	operator: Operator,
+	right: Box<ASTNode>,
+}
+
+impl BinaryExpr {
+	pub fn new(left: Box<ASTNode>, operator: Operator, right: Box<ASTNode>) -> Self {
+		Self {
+			left,
+			operator,
+			right,
+		}
+	}
+}
+
+pub struct GroupingExpr(Box<ASTNode>);
+
+impl GroupingExpr {
+	pub(crate) fn new(expr: Box<ASTNode>) -> Self {
+		Self(expr)
+	}
+}
+
+pub struct UnaryExpr {
+	operator: UnaryOperator,
+	right: Box<ASTNode>,
+}
+
+impl UnaryExpr {
+	pub fn new(operator: UnaryOperator, right: Box<ASTNode>) -> Self {
+		Self { operator, right }
+	}
+}
+
+impl Debug for BinaryExpr {
+	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+		write!(f, "({} {:?} {:?})", self.operator, self.left, self.right)
+	}
+}
+
+impl Debug for GroupingExpr {
+	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+		write!(f, "({:?})", self.0)
+	}
+}
+
+impl Debug for UnaryExpr {
+	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+		write!(f, "({} {:?})", self.operator, self.right)
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+
+	#[test]
+	fn ast_printer() {
+		let ast = ASTNode::BinaryExpr(BinaryExpr {
+			left: Box::new(ASTNode::UnaryExpr(UnaryExpr {
+				operator: UnaryOperator::Bang,
+				right: Box::new(ASTNode::Literal(Literal::Int(1))),
+			})),
+			operator: Operator::EqualEqual,
+			right: Box::new(ASTNode::Literal(Literal::Int(0))),
+		});
+		let formated = format!("{:?}", ast);
+		assert_eq!("(== (! Int(1)) Int(0))", formated);
+	}
+}

src/ast/mod.rs

@@ -0,0 +1,2 @@
+pub mod astnode;
+pub mod parser;

src/ast/parser.rs

@@ -0,0 +1,164 @@
+use super::astnode;
+use super::astnode::{ASTNode, BinaryExpr};
+use crate::lexer::{token, token::TokenType};
+use std::iter;
+use std::result::Result as StdResult;
+
+type Result<T> = StdResult<T, ASTParsingError>;
+
+#[derive(Debug)]
+pub enum ASTParsingError {
+	UnmatchedBrace,
+}
+impl std::fmt::Display for ASTParsingError {
+	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+		todo!()
+	}
+}
+impl std::error::Error for ASTParsingError {}
+
+pub struct Parser<T: Iterator<Item = token::Token>> {
+	token_iter: iter::Peekable<T>,
+}
+
+impl<T: Iterator<Item = token::Token>> Parser<T> {
+	pub fn new(iter: T) -> Parser<T> {
+		Parser {
+			token_iter: iter.peekable(),
+		}
+	}
+	pub fn scan_expressions(&mut self) -> StdResult<Vec<ASTNode>, Vec<ASTParsingError>> {
+		let mut tokens = Vec::new();
+		let mut errors = Vec::new();
+
+		while self.token_iter.peek().is_some() {
+			match self.expression() {
+				Ok(token) => {
+					if errors.is_empty() {
+						tokens.push(token)
+					}
+				}
+				Err(e) => errors.push(e),
+			}
+		}
+		if errors.is_empty() {
+			Ok(tokens)
+		} else {
+			Err(errors)
+		}
+	}
+
+	fn expression(&mut self) -> Result<ASTNode> {
+		self.equality()
+	}
+
+	fn equality(&mut self) -> Result<ASTNode> {
+		let mut node = self.comparison()?;
+		while let Some(o) = self
+			.token_iter
+			.next_if(|t| matches!(t.token_type, TokenType::EqualEqual | TokenType::BangEqual))
+		{
+			node = BinaryExpr::new(
+				Box::new(node),
+				o.token_type.try_into().unwrap(),
+				Box::new(self.comparison()?),
+			)
+			.into();
+		}
+		Ok(node)
+	}
+
+	fn comparison(&mut self) -> Result<ASTNode> {
+		let mut node = self.term()?;
+
+		while let Some(o) = self.token_iter.next_if(|t| {
+			matches!(
+				t.token_type,
+				TokenType::Greater
+					| TokenType::GreaterEqual
+					| TokenType::Less | TokenType::LessEqual
+			)
+		}) {
+			node = BinaryExpr::new(
+				Box::new(node),
+				o.token_type.try_into().unwrap(),
+				Box::new(self.comparison()?),
+			)
+			.into();
+		}
+		Ok(node)
+	}
+
+	fn term(&mut self) -> Result<ASTNode> {
+		let mut node = self.factor()?;
+
+		while let Some(o) = self
+			.token_iter
+			.next_if(|t| matches!(t.token_type, TokenType::Minus | TokenType::Plus))
+		{
+			node = BinaryExpr::new(
+				Box::new(node),
+				o.token_type.try_into().unwrap(),
+				Box::new(self.comparison()?),
+			)
+			.into()
+		}
+		Ok(node)
+	}
+
+	fn factor(&mut self) -> Result<ASTNode> {
+		let mut node = self.unary()?;
+
+		while let Some(o) = self
+			.token_iter
+			.next_if(|t| matches!(t.token_type, TokenType::Star | TokenType::Slash))
+		{
+			node = BinaryExpr::new(
+				Box::new(node),
+				o.token_type.try_into().unwrap(),
+				Box::new(self.comparison()?),
+			)
+			.into();
+		}
+		Ok(node)
+	}
+
+	fn unary(&mut self) -> Result<ASTNode> {
+		if let Some(op) = self
+			.token_iter
+			.next_if(|t| matches!(t.token_type, TokenType::Bang | TokenType::Minus))
+		{
+			let right = Box::new(self.unary()?);
+			Ok(ASTNode::UnaryExpr(astnode::UnaryExpr::new(
+				op.token_type.try_into().unwrap(),
+				right,
+			)))
+		} else {
+			self.primary()
+		}
+	}
+
+	fn primary(&mut self) -> Result<ASTNode> {
+		let node = match self.token_iter.next().map(|it| it.token_type) {
+			Some(TokenType::False) => ASTNode::Literal(astnode::Literal::Bool(false)),
+			Some(TokenType::True) => ASTNode::Literal(astnode::Literal::Bool(false)),
+			Some(TokenType::Int(i)) => ASTNode::Literal(astnode::Literal::Int(i)),
+			Some(TokenType::String(i)) => ASTNode::Literal(astnode::Literal::String(i)),
+			Some(TokenType::Float(f)) => ASTNode::Literal(astnode::Literal::Float(f)),
+			Some(TokenType::LeftParen) => {
+				let expr = self.expression()?;
+				let group = astnode::GroupingExpr::new(Box::new(expr));
+				match self
+					.token_iter
+					.next_if(|v| matches!(v.token_type, TokenType::RightParen))
+				{
+					Some(_) => return Ok(group.into()),
+					None => return Err(todo!()),
+				}
+			}
+			Some(a) => panic!("{:#?}", a),
+			None => todo!(),
+		};
+		Ok(node)
+	}
+}

src/lexer/mod.rs

@@ -10,7 +10,7 @@ use self::token::Token;
 
 #[derive(Debug)]
 pub struct Lexer<'a> {
-	source: &'a str,
+	_source: &'a str,
 	source_iter: iter::Peekable<Chars<'a>>,
 	line: usize,
 }
@@ -18,7 +18,7 @@ pub struct Lexer<'a> {
 impl<'a> Lexer<'a> {
 	pub fn new(code: &'a str) -> Lexer<'a> {
 		return Lexer {
-			source: code,
+			_source: code,
 			source_iter: code.chars().peekable(),
 			line: 0,
 		};
@@ -39,7 +39,6 @@ impl<'a> Lexer<'a> {
 				None => (),
 			}
 		}
-		tokens.push(self.get_token(token::TokenType::Eof));
 
 		if errors.is_empty() {
 			Ok(tokens)
@@ -81,6 +80,7 @@ impl<'a> Lexer<'a> {
 			'+' => self.get_token(token::TokenType::Plus),
 			';' => self.get_token(token::TokenType::Semicolon),
 			'*' => self.get_token(token::TokenType::Star),
+			'/' => self.get_token(token::TokenType::Slash),
 			'!' => self.get_token_if_next_eq_or(
 				'=',
 				token::TokenType::BangEqual,
@@ -94,7 +94,7 @@ impl<'a> Lexer<'a> {
 			'<' => self.get_token_if_next_eq_or(
 				'=',
 				token::TokenType::LessEqual,
-				token::TokenType::Equal,
+				token::TokenType::Less,
 			),
 			'>' => self.get_token_if_next_eq_or(
 				'=',

src/lexer/token.rs

@@ -45,5 +45,4 @@ pub enum TokenType {
 	True,
 	Let,
 	While,
-	Eof,
 }

src/main.rs

@@ -1,3 +1,4 @@
+mod ast;
 mod lexer;
 
 use lexer::Lexer;
@@ -27,7 +28,12 @@ fn run_repl() {
 
 fn run(code: &str) -> Result<(), Vec<lexer::LexingError>> {
 	let mut lexer = Lexer::new(code);
-	println!("{:?}", lexer.scan_tokens()?);
+	let tokens = lexer.scan_tokens()?;
+	println!("{:?}", tokens);
+	let mut parser = crate::ast::parser::Parser::new(tokens.into_iter());
+	let expressions = parser.scan_expressions().unwrap();
+	println!("{:?}", expressions);
+
 	Ok(())
 }