Syntax error repair with dynamic valid length in LR-based parsers

In this paper, we present a syntax error repair to decide spurious errors using dynamic valid length. When the compiler encounters a syntax error, it usually attempts to restart parsing to check the remainder of the input for any further errors. One common method of error repair is to repair the input by insertion or deletion or substitution. After repair, the repair method should decide whether the error is a spurious error or not. In order to decide this, Conventional methods adopt a fixed valid length. However it is insufficient. In our method, valid length isnpsilat fixed on ahead. Our method tries all candidates for an error and decides that the one which has longest length is not a spurious error. Since the effectivity of our method was shown, the benchmark program was executed by our method and the conventional method using a fixed valid length. Compared with the conventional method, the proposed method can reduce approximately 90% of non-correcting errors and increase 23.1% of correcting errors.