rewrite 1
This commit is contained in:
+8
-251
@@ -1,255 +1,12 @@
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#[derive(Debug, PartialEq, Clone)]
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enum Token {
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Plus,
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Minus,
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Star,
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Slash,
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Equals,
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Semicolon,
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LParen,
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RParen,
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Identifier(String),
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Number(i64),
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EOF,
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}
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use variable::Variables;
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fn tokenize(input: &str) -> Vec<Token> {
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let mut tokens = Vec::new();
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let chars: Vec<char> = input.chars().collect();
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let mut i = 0;
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while i < chars.len() {
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match chars[i] {
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' ' | '\t' | '\n' | '\r' => i += 1,
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'+' => {
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tokens.push(Token::Plus);
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i += 1;
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}
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'-' => {
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tokens.push(Token::Minus);
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i += 1;
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}
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'*' => {
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tokens.push(Token::Star);
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i += 1;
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}
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'/' => {
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tokens.push(Token::Slash);
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i += 1;
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}
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'=' => {
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tokens.push(Token::Equals);
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i += 1;
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}
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';' => {
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tokens.push(Token::Semicolon);
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i += 1;
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}
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'(' => {
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tokens.push(Token::LParen);
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i += 1;
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}
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')' => {
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tokens.push(Token::RParen);
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i += 1;
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}
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'0'..='9' => {
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let mut num = 0;
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while i < chars.len() && chars[i].is_digit(10) {
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num = num * 10 + chars[i].to_digit(10).unwrap() as i64;
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i += 1;
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}
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tokens.push(Token::Number(num));
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}
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'a'..='z' | 'A'..='Z' => {
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let mut id = String::new();
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while i < chars.len() && (chars[i].is_alphanumeric() || chars[i] == '_') {
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id.push(chars[i]);
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i += 1;
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}
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match id.as_str() {
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_ => tokens.push(Token::Identifier(id)),
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}
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}
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_ => panic!("Unexpected character: {}", chars[i]),
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}
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}
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tokens.push(Token::EOF);
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tokens
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}
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#[derive(Debug)]
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enum ASTNode {
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Number(i64),
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Identifier(String),
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BinaryOp(Box<ASTNode>, Token, Box<ASTNode>),
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Assignment(String, Box<ASTNode>),
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Print(Box<ASTNode>),
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Let(String, Box<ASTNode>),
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Sequence(Vec<ASTNode>),
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}
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struct Parser {
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tokens: Vec<Token>,
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current_token: Token,
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pos: usize,
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}
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impl Parser {
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fn new(tokens: Vec<Token>) -> Self {
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Self {
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tokens: tokens.clone(),
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current_token: tokens[0].clone(),
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pos: 0,
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}
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}
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fn eat(&mut self, token: Token) {
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if self.current_token == token {
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self.pos += 1;
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self.current_token = self.tokens[self.pos].clone();
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} else {
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panic!("Unexpected token: {:?}", self.current_token);
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}
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}
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fn factor(&mut self) -> ASTNode {
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match self.current_token.clone() {
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Token::Number(value) => {
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self.eat(Token::Number(value));
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ASTNode::Number(value)
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}
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Token::Identifier(name) => {
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self.eat(Token::Identifier(name.clone()));
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ASTNode::Identifier(name)
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}
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Token::LParen => {
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self.eat(Token::LParen);
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let expr = self.expression();
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self.eat(Token::RParen);
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expr
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}
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_ => panic!("Unexpected token: {:?}", self.current_token),
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}
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}
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fn term(&mut self) -> ASTNode {
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let mut node = self.factor();
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while self.current_token == Token::Star || self.current_token == Token::Slash {
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let token = self.current_token.clone();
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self.eat(token.clone());
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node = ASTNode::BinaryOp(Box::new(node), token, Box::new(self.factor()));
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}
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node
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}
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fn expression(&mut self) -> ASTNode {
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let mut node = self.term();
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while self.current_token == Token::Plus || self.current_token == Token::Minus {
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let token = self.current_token.clone();
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self.eat(token.clone());
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node = ASTNode::BinaryOp(Box::new(node), token, Box::new(self.term()));
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}
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node
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}
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fn statement(&mut self) -> ASTNode {
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match self.current_token.clone() {
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Token::Identifier(name) => {
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self.eat(Token::Identifier(name.clone()));
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self.eat(Token::Equals);
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let expr = self.expression();
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self.eat(Token::Semicolon);
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ASTNode::Assignment(name, Box::new(expr))
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}
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_ => panic!("Unexpected token: {:?}", self.current_token),
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}
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}
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fn parse(&mut self) -> ASTNode {
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let mut statements = Vec::new();
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while self.current_token != Token::EOF {
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statements.push(self.statement());
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}
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ASTNode::Sequence(statements)
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}
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}
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use std::collections::HashMap;
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struct Interpreter {
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symbol_table: HashMap<String, i64>,
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}
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impl Interpreter {
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fn new() -> Self {
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Self {
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symbol_table: HashMap::new(),
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}
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}
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fn evaluate(&mut self, node: &ASTNode) -> i64 {
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match node {
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ASTNode::Number(value) => *value,
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ASTNode::Identifier(name) => *self.symbol_table.get(name).expect("Undefined variable"),
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ASTNode::BinaryOp(left, token, right) => {
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let left_val = self.evaluate(left);
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let right_val = self.evaluate(right);
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match token {
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Token::Plus => left_val + right_val,
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Token::Minus => left_val - right_val,
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Token::Star => left_val * right_val,
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Token::Slash => left_val / right_val,
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_ => panic!("Unexpected binary operator"),
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}
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}
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ASTNode::Assignment(name, expr) => {
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let value = self.evaluate(expr);
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self.symbol_table.insert(name.clone(), value);
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value
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}
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ASTNode::Let(name, expr) => {
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let value = self.evaluate(expr);
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self.symbol_table.insert(name.clone(), value);
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value
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}
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ASTNode::Print(expr) => {
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let value = self.evaluate(expr);
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println!("{}", value);
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value
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}
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ASTNode::Sequence(statements) => {
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for statement in statements {
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self.evaluate(statement);
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}
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0
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}
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}
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}
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}
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mod parser;
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mod transpiler;
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mod utils;
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mod variable;
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fn main() {
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let input = "
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let x = 5;
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let y = x + 3;
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print y;
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x = y * 2;
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print x;
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";
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let tokens = tokenize(input);
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println!("Tokens: {:?}", tokens);
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let mut parser = Parser::new(tokens);
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let ast = parser.parse();
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println!("AST: {:?}", ast);
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let mut interpreter = Interpreter::new();
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interpreter.evaluate(&ast);
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let mut vars = Variables::new();
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let out = transpiler::Transpiler::default().transpile(r#"int x"#.to_string(), 0, &mut vars);
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println!("{out}");
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}
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