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 *
 * Software distributed under the License is distributed on an "AS
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 * Copyright (C) 2005 Thomas E Enebo <enebo@acm.org>
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package org.jruby.lexer.yacc;

import org.jruby.runtime.PositionAware;

/**
 * This interface is the combination of two needs:  1) A Ruby interpreter position (for warnings 
 * and errors).  The interpreter only cares about filename and endLine.  2) A IDE position (offsets
 * for showing ranges of grammatical elements).
 * 
 * The offsets represent positions 'between' characters.  So a variable 'abc' has a startOffset
 * of 0 and an endOffset of 3 ( 0a1b2c3 ).
 * 
 */
public interface ISourcePosition extends PositionAware {
    /**
     * Which file does this source position live in?
     * 
     * @return name of the source file.
     */
	public String getFile();
    
    /**
     * Which is the first(start) line that this source position occurs on (zero-based)
     * @return
     */
	public int getStartLine();


    /** For nodes which are added to the AST which are not proper syntactical elements. */
    public static final ISourcePosition INVALID_POSITION = new ISourcePosition() {
        public String getFile() {
            return "dummy";
        }

        public int getStartLine() {
            return -1;
        }

        public int getLine() {
            return -1;
        }
    };
}
