package edu.stanford.nlp.io;
import java.io.IOException;
import java.io.Reader;
/**
* A Lexer interface to be used with {@link edu.stanford.nlp.process.LexerTokenizer}. You can put a {@link Reader} inside
* a Lexer with the {@link #yyreset} method. An easy way to build classes implementing this
* interface is with JFlex (http://jflex.de). Just make sure to include the following in the
* JFlex source file
* <p/>
* <p> In the <i>Options and Macros</i> section of the source file, include
* <p/>
* %class JFlexDummyLexer<br>
* %standalone<br>
* %unicode<br>
* %int<br>
* <p><br>
* %implements edu.stanford.nlp.io.Lexer<br>
* <br>
* %{<br>
* public void pushBack(int n) {<br>
* yypushback(n);<br>
* }<br>
* <br>
* public int getYYEOF() {<br>
* return YYEOF;<br>
* }<br>
* %}<br>
* <p/>
* Alternatively, you can customize your own lexer and get lots of
* flexibility out.
*
* @author Roger Levy
*/
public interface Lexer {
public int ACCEPT = 1;
public int IGNORE = 0;
/**
* Gets the next token from input and returns an integer value
* signalling what to do with the token.
*/
public int yylex() throws IOException;
/**
* returns the matched input text region
*/
public String yytext();
/**
* Pushes back <code>length</code> character positions in the
* lexer. Conventionally used to push back exactly one token.
*/
public void pushBack(int length);
/**
* returns value for YYEOF
*/
public int getYYEOF();
/**
* put a {@link Reader} inside the Lexer.
*/
public void yyreset(Reader r) throws IOException;
}
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