use super::*;
pub struct ScanState<S: ScanFn> {
pub first: S::OutputItem,
pub next: S,
}
pub trait ScanFn: Sized {
type InputItem;
type InputResult;
type OutputItem;
type OutputResult;
fn map_input(self, input: Self::InputItem) -> ScanState<Self>;
fn map_result(self, result: Self::InputResult) -> Self::OutputResult;
}
pub struct ScanWrap<S: ScanFn>(S);
impl<S: ScanFn> FlatScanFn for ScanWrap<S> {
type InputItem = S::InputItem;
type InputResult = S::InputResult;
type OutputList = OptionList<S::OutputItem, Self>;
type EndList = OptionList<S::OutputItem, Id<S::OutputResult>>;
fn map_item(self, input: Self::InputItem) -> Self::OutputList {
let ScanState { first, next } = self.0.map_input(input);
OptionList::Some {
first,
end: ScanWrap(next),
}
}
fn map_result(self, result: Self::InputResult) -> Self::EndList {
OptionList::End(Id::new(self.0.map_result(result)))
}
}
pub trait Scan
where
Self: ListFn,
Self::End: ResultFn,
{
fn scan<S: ScanFn<InputItem = Self::Item, InputResult = <Self::End as ResultFn>::Result>>(
self,
scan: S,
) -> FlatScanState<Self, ScanWrap<S>> {
self.flat_scan(ScanWrap(scan))
}
}
impl<L> Scan for L
where
Self: ListFn,
Self::End: ResultFn,
{
}