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#[derive(Debug)]
pub enum Token {
Operator(char),
Num(f64),
LParen,
RParen
}
#[derive(Debug)]
pub struct Node {
value: Option<Token>,
left: Box<Option<Node>>,
right: Box<Option<Node>>
}
impl Node {
fn new() -> Node {
Node {
value: None,
left: Box::new(None),
right: Box::new(None)
}
}
fn set_val(&mut self, val: Token) {
self.value = Some(val);
}
fn set_left(&mut self, val: Node) {
self.left = Box::new(Some(val));
}
fn set_right(&mut self, val: Node) {
self.right = Box::new(Some(val));
}
}
fn main() {
let input = "11 + (1 + 2(3))";
let input = input.replace(" ", "");
let lexed = lexer(&input);
println!("{:?}", lexed);
}
fn lexer(input: &str) -> Result<Vec<Token>, String> {
let mut num_vec: String = String::new();
let mut result: Vec<Token> = vec![];
for letter in input.chars() {
match letter {
'0'...'9' | '.' => {
num_vec.push(letter);
},
'+' | '-' | '/' | '*' | '^' => {
// parse num buf
let parse_num = num_vec.parse::<f64>().ok();
if let Some(x) = parse_num {
result.push(Token::Num(x));
num_vec.clear();
}
// finish
result.push(Token::Operator(letter));
},
'(' => {
// parse num buf
let parse_num = num_vec.parse::<f64>().ok();
if let Some(x) = parse_num {
result.push(Token::Num(x));
result.push(Token::Operator('*'));
num_vec.clear();
}
// finish
result.push(Token::RParen);
},
')' => {
// parse num buf
let parse_num = num_vec.parse::<f64>().ok();
if let Some(x) = parse_num {
result.push(Token::Num(x));
num_vec.clear();
}
// finish
result.push(Token::LParen);
}
_ => {
return Err(format!("Unexpected character: {}", letter))
}
}
}
Ok(result)
}
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