Fischer et al. have proposed the locally least-cast error repair model for LL and LR parsing method. Choe and Chang have proposed an efficient algorithm for computing the locally least-cost insertion string for the LR-based parsers. In that model, only one lookahead symbol is referred to find an error repair string, and processed symbols are considered to be correct. Although it is very simple and fast, the prerformance of error repairs may be improved adding more information.
In this thesis, the locally least-cost error repair model si extended to k lookahead symbols, and a practical algorithm is proposed with two lookahead symbols. A backtracking algorithm which recovers shifter symbols is formalized. The proposed extended error repair model uses the backtracking algorithm and two lookahead symbols, which is implemented with KAIST Parser Generating System (KPGS). And the system is tested with the Pascal program testing suits in order to show the improved performance.