unit tok;

// What the lexer produces. A token does not hold the text it came from: R4
// keeps borrows out of aggregate storage, so it records where in the source it
// starts and how long it is, and the source travels beside it.

pub enum Kind {
    End,
    Name,
    Number,
    Text,
    Punct,
    Keyword,
    Bad,
}

pub struct Token {
    pub kind: Kind,
    pub from: usize,
    pub len: usize,
    pub line: usize,
}

pub fn text(src: []u8, t: Token) -> []u8 {
    return src[t.from..t.from + t.len];
}

pub fn name_of(k: Kind) -> []u8 {
    match k {
        End => { return "end"; }
        Name => { return "name"; }
        Number => { return "number"; }
        Text => { return "text"; }
        Punct => { return "punct"; }
        Keyword => { return "keyword"; }
        Bad => { return "bad"; }
    }
    return "?";
}