treaty -


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use crate::{
    nameable,
    protocol::{walker::HintMeta, ControlFlowFor, Effect, SyncEffect, Visitor},
};

pub trait Sequence<'a, 'ctx: 'a, E: Effect<'ctx> = SyncEffect> {
    fn visit(
        &'a mut self,
        scope: &'a mut dyn for<'b> SequenceScope<'b, 'ctx, E>,
    ) -> ControlFlowFor<'a, 'ctx, E>;
}

nameable! {
    pub struct Name['a, 'ctx: 'a, E];

    impl [E] for dyn Sequence<'a, 'ctx, E> + 'a where {
        E: Effect<'ctx>,
        'ctx: 'a
    }

    impl [E] where dyn Sequence<'a, 'ctx, E> + 'a {
        E: Effect<'ctx>,
        'ctx: 'a
    }
}

pub trait SequenceScope<'a, 'ctx: 'a, E = SyncEffect>
where
    E: Effect<'ctx> + Effect<'ctx, Status>,
{
    fn next(&'a mut self, visitor: Visitor<'a, 'ctx, E>) -> ControlFlowFor<'a, 'ctx, E, Status>;
}

#[derive(PartialEq, Eq, PartialOrd, Ord, Copy, Clone, Debug)]
pub enum Status {
    Done,
    Continue,
}

#[derive(Default)]
pub struct Known {
    pub len: (usize, Option<usize>),
}

pub struct Hint {
    pub len: (usize, Option<usize>),
}

impl<'a, 'ctx: 'a, E: Effect<'ctx>> HintMeta<'a, 'ctx> for dyn Sequence<'a, 'ctx, E> + '_ {
    type Known = Known;

    type Hint = Hint;
}