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<Paper uid="P89-1017">
  <Title>How to cover a grammar Ren6 Leermakers</Title>
  <Section position="12" start_page="141" end_page="141" type="concl">
    <SectionTitle>
10 Conclusions
</SectionTitle>
    <Paragraph position="0"> We studied parsing of general context-free languages, by splitting the process into two parts. Firstly, the grammar is turned into bilinear grammar format, and subsequently a general parser for bilinear grammars is applied. Our view on the relation between parsers and covers is similar to the work on covers of Nijholt \[7\] for grammars that are deterministically parsable.</Paragraph>
    <Paragraph position="1"> We established that the Lung algorithm for simulating pushdown automata, hides a prescription for deriving bilinear covers from automata that satisfy certain constraints. Reversely, the LR-parser construction technique has been presented as a way to derive automata from certain bilinear grammars.</Paragraph>
    <Paragraph position="2"> We found that the Earley algorithm is intimately related to an automaton that simulates non-deterministic LL-parsing and, furthermore, that non-deterministic LR-automata provide general parsers for context-free grammars, with the same complexity as the Earley algorithm. It should be noted, however, that there are as many parsers with this property, as there are ways to obtain bilinear covers for a given grammar.</Paragraph>
  </Section>
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