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<Paper uid="E91-1052">
  <Title>An Extension of Earley's Algorithm for S-Attributed Grammars</Title>
  <Section position="5" start_page="0" end_page="0" type="concl">
    <SectionTitle>
5. Conclusions and Implementalion Status
</SectionTitle>
    <Paragraph position="0"> This paper presented and extension of Earley's algorithm to S-attributed grammars. Combining on-line semantic evaluation with the execution of syntactic actions, the algorithm is an effective realization of attribute-directed parsing, as proposed by Watt (1980) and Jones and Madsen (1980). Although the algorithm is a recognizer, it computes the semantic values associated with each derivation of the input string, and hence need not be extended to compute tree representations. In attribute grammars with conditions on productions, the values of attributes already evaluated unay be used to guide the parsing process, reducing the number of states! that may be generated by the algorithm.</Paragraph>
    <Paragraph position="1"> The extension of the algorithm has been written in &amp;quot;C&amp;quot;, using an efficient &amp;quot;C&amp;quot; implementation of Earley's original algorithm (Chamorro and Correa, 1990), and is currently being tested on small grammars. The extended algorithm will be the kernel of ANDES-l, a programming environment for attribute grammars, intended for natural language applications.</Paragraph>
  </Section>
class="xml-element"></Paper>