ast: improved ast interface usage
ast: improved ast interface usage

LivelyKernel/LivelyKernel,LivelyKernel/LivelyKernel,NikolaySuslov/LivelyKernel,NikolaySuslov/LivelyKernel,pascience/LivelyKernel,NikolaySuslov/LivelyKernel,pascience/LivelyKernel,pascience/LivelyKernel,LivelyKernel/LivelyKernel