internal sealed override bool TryParse(ref ParseState <TToken> state, ref ExpectedCollector <TToken> expecteds, out T result)
{
// start buffering the input
state.PushBookmark();
var success = _parser.TryParse(ref state, ref expecteds, out result);
if (!success)
{
// return to the start of the buffer and discard the bookmark
state.Rewind();
return(false);
}
// discard the buffer
state.PopBookmark();
return(true);
}
internal sealed override InternalResult <T> Parse(ref ParseState <TToken> state)
{
// start buffering the input
state.PushBookmark();
var result = _parser.Parse(ref state);
if (!result.Success)
{
// return to the start of the buffer and discard the bookmark
state.Rewind();
return(InternalResult.Failure <T>(false));
}
// discard the buffer
state.PopBookmark();
return(result);
}
internal override InternalResult <U> Parse(ref ParseState <TToken> state)
{
var start = state.Location;
state.PushBookmark(); // don't discard input buffer
var result = _parser.Parse(ref state);
if (!result.Success)
{
state.PopBookmark();
return(InternalResult.Failure <U>(result.ConsumedInput));
}
var delta = state.Location - start;
var val = _selector(state.LookBehind(delta), result.Value);
state.PopBookmark();
return(InternalResult.Success <U>(val, result.ConsumedInput));
}
internal sealed override bool TryParse(ref ParseState <TToken> state, ref ExpectedCollector <TToken> expecteds, out U result)
{
var start = state.Location;
state.PushBookmark(); // don't discard input buffer
var success = _parser.TryParse(ref state, ref expecteds, out var result1);
if (!success)
{
state.PopBookmark();
result = default;
return(false);
}
var delta = state.Location - start;
result = _selector(state.LookBehind(delta), result1);
state.PopBookmark();
return(true);
}