Created
January 30, 2017 12:49
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enum Token { | |
Start, | |
End, | |
Value(i32), | |
} | |
enum Node { | |
List(Vec<Node>), | |
Value(i32), | |
} | |
fn main() { | |
let v = vec![Token::Start, Token::Value(1), Token::End]; | |
parse(&v); | |
} | |
fn parse(tokens: &Vec<Token>) -> Node { | |
let mut root: Vec<Node> = vec![]; | |
{ | |
tokens.into_iter().fold(vec![&mut root], handle_token); | |
} | |
Node::List(root) | |
} | |
fn handle_token<'a>(mut stack: Vec<&'a mut Vec<Node>>, token: &Token) -> Vec<&'a mut Vec<Node>> { | |
match *token { | |
Token::Start => { | |
stack[0].push(Node::List(vec![])); // Add the new node to the tree | |
match stack[0][0] { | |
Node::List(ref mut the_vec) => stack.push(the_vec), // Add a mutable reference to the new vector so that subsequent nodes will become children of this Node | |
_ => panic!(), | |
}; | |
}, | |
Token::End => { stack.pop(); }, | |
Token::Value(v) => stack[0].push(Node::Value(v)), | |
} | |
stack | |
} |
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