opu.lljvm-python.0.2.0-EXPERIMENTAL.source-code.terminal Maven / Gradle / Ivy
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package java_cup;
import java.util.Hashtable;
import java.util.Enumeration;
/** This class represents a terminal symbol in the grammar. Each terminal
* has a textual name, an index, and a string which indicates the type of
* object it will be implemented with at runtime (i.e. the class of object
* that will be returned by the scanner and pushed on the parse stack to
* represent it).
*
* @version last updated: 11/25/95
* @author Scott Hudson
*/
public class terminal extends symbol {
/*-----------------------------------------------------------*/
/*--- Constructor(s) ----------------------------------------*/
/*-----------------------------------------------------------*/
/** Full constructor.
* @param nm the name of the terminal.
* @param tp the type of the terminal.
*/
public terminal(String nm, String tp)
{
/* superclass does most of the work */
super(nm, tp);
/* add to set of all terminals and check for duplicates */
Object conflict = _all.put(nm,this);
if (conflict != null)
// can't throw an execption here because this is used in static
// initializers, so we do a crash instead
// was:
// throw new internal_error("Duplicate terminal (" + nm + ") created");
(new internal_error("Duplicate terminal (" + nm + ") created")).crash();
/* assign a unique index */
_index = next_index++;
/* add to by_index set */
_all_by_index.put(new Integer(_index), this);
}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/** Constructor with default type.
* @param nm the name of the terminal.
*/
public terminal(String nm)
{
this(nm, null);
}
/*-----------------------------------------------------------*/
/*--- (Access to) Static (Class) Variables ------------------*/
/*-----------------------------------------------------------*/
/** Table of all terminals. Elements are stored using name strings as
* the key
*/
protected static Hashtable _all = new Hashtable();
/** Access to all terminals. */
public static Enumeration all() {return _all.elements();};
/** Lookup a terminal by name string. */
public static terminal find(String with_name)
{
if (with_name == null)
return null;
else
return (terminal)_all.get(with_name);
}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/** Table of all terminals indexed by their index number. */
protected static Hashtable _all_by_index = new Hashtable();
/** Lookup a terminal by index. */
public static terminal find(int indx)
{
Integer the_indx = new Integer(indx);
return (terminal)_all_by_index.get(the_indx);
}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/** Total number of terminals. */
public static int number() {return _all.size();};
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/** Static counter to assign unique index. */
protected static int next_index = 0;
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/** Special terminal for end of input. */
public static final terminal EOF = new terminal("EOF");
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/** special terminal used for error recovery */
public static final terminal error = new terminal("error");
/*-----------------------------------------------------------*/
/*--- General Methods ---------------------------------------*/
/*-----------------------------------------------------------*/
/** Report this symbol as not being a non-terminal. */
public boolean is_non_term()
{
return false;
}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/** Convert to a string. */
public String toString()
{
return super.toString() + "[" + index() + "]";
}
/*-----------------------------------------------------------*/
};