use crate::*;

#[derive(Debug, Clone, Default, PartialEq)]
pub struct Ast(pub AstValue);

/// The abstract syntax tree (AST) can be produced from the CST
/// by cloning source slices into owned [Arc] values.
pub type AstValue = DslValue<Arc<str>, VecDeque<Ast>>;

//#[derive(Debug, Clone, Default, PartialEq)]
//pub struct AstIter();

impl<'src> From<Cst<'src>> for Ast {
    fn from (token: Cst<'src>) -> Self {
        token.value().into()
    }
}

impl<'src> From<CstValue<'src>> for Ast {
    fn from (value: CstValue<'src>) -> Self {
        Self(match value {
            DslValue::Nil       => DslValue::Nil,
            DslValue::Err(e)    => DslValue::Err(e),
            DslValue::Num(u)    => DslValue::Num(u),
            DslValue::Sym(s)    => DslValue::Sym(s.into()),
            DslValue::Key(s)    => DslValue::Key(s.into()),
            DslValue::Str(s)    => DslValue::Str(s.into()),
            DslValue::Exp(d, x) => DslValue::Exp(d, x.map(|x|x.into()).collect()),
        })
    }
}