org.antlr.runtime.TokenSource Maven / Gradle / Ivy
/*
[The "BSD licence"]
Copyright (c) 2005-2006 Terence Parr
All rights reserved.
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*/
package org.antlr.runtime;
/** A source of tokens must provide a sequence of tokens via nextToken()
* and also must reveal it's source of characters; CommonToken's text is
* computed from a CharStream; it only store indices into the char stream.
*
* Errors from the lexer are never passed to the parser. Either you want
* to keep going or you do not upon token recognition error. If you do not
* want to continue lexing then you do not want to continue parsing. Just
* throw an exception not under RecognitionException and Java will naturally
* toss you all the way out of the recognizers. If you want to continue
* lexing then you should not throw an exception to the parser--it has already
* requested a token. Keep lexing until you get a valid one. Just report
* errors and keep going, looking for a valid token.
*/
public interface TokenSource {
/** Return a Token object from your input stream (usually a CharStream).
* Do not fail/return upon lexing error; keep chewing on the characters
* until you get a good one; errors are not passed through to the parser.
*/
public Token nextToken();
}