On parsing LL-languages

On Parsing LL-Languages

Usually, a parser for an LL(k)-grammar G is a deterministic pushdown transducer which produces a leftmost derivation for a given input string x 2 L(G). Ukkonen 5] has given a family of LL(2)-grammars proving that every parser for these grammars has exponential size. If we add to a parser the possibility to manipulate a constant number of pointers which point to positions within the constructed ...

On the Parsing of LL-Regular Grammars

Unifying LL and LR parsing

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 automato...

LLLR Parsing: a Combination of LL and LR Parsing

A new parsing method called LLLR parsing is defined and a method for producing LLLR parsers is described. An LLLR parser uses an LL parser as its backbone and parses as much of its input string using LL parsing as possible. To resolve LL conflicts it triggers small embedded LR parsers. An embedded LR parser starts parsing the remaining input and once the LL conflict is resolved, the LR parser p...

An Incremental LL(1) Parsing Algorithm

Given a parse tree for a sentence xzy and a string Z, an incremental parser builds the parse tree for the sentence xZy by reusing as much of the parse tree for xzy as possible. The incremental LL(1) parsing algorithm in this paper makes use of a break-point table to identify reusable subtrees of the original parse tree in building the new parse tree. The break-point table may be computed from t...