use crate::*;
use std::sync::Arc;
use std::borrow::Cow;

#[derive(Debug, Copy, Clone, Default, PartialEq)]
pub struct AstIter;
impl<'source> From<SourceIter<'source>> for AstIter {
    fn from (source: SourceIter<'source>) -> Self {
        Self // TODO
    }
}
/// Owns its values, and has no metadata.
pub type Ast = Value<Arc<str>, AstIter>;
impl<'source> From<CstToken<'source>> for Ast {
    fn from (token: CstToken<'source>) -> Self {
        token.value().into()
    }
}
impl<'source> From<CstValue<'source>> for Ast {
    fn from (value: CstValue<'source>) -> Self {
        use Value::*;
        match value {
            Nil    => Nil,
            Err(e) => Err(e),
            Num(u) => Num(u),
            Sym(s) => Sym(s.into()),
            Key(s) => Key(s.into()),
            Str(s) => Str(s.into()),
            Exp(d, x) => Exp(d, x.into()),
        }
    }
}