Unifying LL and LR parsing
نویسنده
چکیده
In parsing theory, LL parsing and LR parsing are regarded to be two distinct methods. In this paper the relation between these methods is cla-riied. As shown in literature on parsing theory, for every context-free grammar, a so-called non-deterministic LR(0) automaton can be constructed. Here, we show, that traversing this automaton in a special way is equivalent to LL(1) parsing. This automaton can be transformed into a deterministic LR-automaton. The description of a method to traverse this automaton results into a new formulation of the LR parsing algorithm. Having obtained in this way a relationship between LL and LR parsing, the LL(1) class is characterised, using several LR-classes.
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