1 files changed, 301 insertions, 0 deletions
diff --git a/src/syntaxParser/java_cup/non_terminal.java b/src/syntaxParser/java_cup/non_terminal.java
new file mode 100644
index 0000000..9354a7f
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+++ b/src/syntaxParser/java_cup/non_terminal.java
@@ -0,0 +1,301 @@
+package java_cup;
+
+import java.util.Hashtable;
+import java.util.Enumeration;
+
+/** This class represents a non-terminal symbol in the grammar.  Each
+ *  non 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 pushed on the parse stack to represent it). 
+ *
+ * @version last updated: 11/25/95
+ * @author  Scott Hudson
+ */
+
+public class non_terminal extends symbol {
+
+  /*-----------------------------------------------------------*/
+  /*--- Constructor(s) ----------------------------------------*/
+  /*-----------------------------------------------------------*/
+
+  /** Full constructor.
+   * @param nm  the name of the non terminal.
+   * @param tp  the type string for the non terminal.
+   */
+  public non_terminal(String nm, String tp) 
+    {
+      /* super class does most of the work */
+      super(nm, tp);
+
+      /* add to set of all non terminals and check for duplicates */
+      Object conflict = _all.put(nm,this);
+      if (conflict != null)
+	// can't throw an exception here because these are used in static
+	// initializers, so we crash instead
+	// was: 
+	// throw new internal_error("Duplicate non-terminal ("+nm+") created");
+	(new internal_error("Duplicate non-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 non terminal.
+   */
+  public non_terminal(String nm) 
+    {
+      this(nm, null);
+    }
+
+  /*-----------------------------------------------------------*/
+  /*--- (Access to) Static (Class) Variables ------------------*/
+  /*-----------------------------------------------------------*/
+
+  /** Table of all non-terminals -- elements are stored using name strings 
+   *  as the key 
+   */
+  protected static Hashtable _all = new Hashtable();
+
+  /** Access to all non-terminals. */
+  public static Enumeration all() {return _all.elements();}
+
+  /** lookup a non terminal by name string */ 
+  public static non_terminal find(String with_name)
+    {
+      if (with_name == null)
+        return null;
+      else 
+        return (non_terminal)_all.get(with_name);
+    }
+
+  /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
+
+  /** Table of all non terminals indexed by their index number. */
+  protected static Hashtable _all_by_index = new Hashtable();
+
+  /** Lookup a non terminal by index. */
+  public static non_terminal find(int indx)
+    {
+      Integer the_indx = new Integer(indx);
+
+      return (non_terminal)_all_by_index.get(the_indx);
+    }
+
+  /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
+
+  /** Total number of non-terminals. */
+  public static int number() {return _all.size();}
+
+  /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
+
+  /** Static counter to assign unique indexes. */
+  protected static int next_index = 0;
+
+  /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
+
+  /** Static counter for creating unique non-terminal names */
+  static protected int next_nt = 0;
+
+  /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
+
+  /** special non-terminal for start symbol */
+  public static final non_terminal START_nt = new non_terminal("$START");
+
+  /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
+
+  /** flag non-terminals created to embed action productions */
+  public boolean is_embedded_action = false; /* added 24-Mar-1998, CSA */
+
+  /*-----------------------------------------------------------*/
+  /*--- Static Methods ----------------------------------------*/
+  /*-----------------------------------------------------------*/
+	 
+  /** Method for creating a new uniquely named hidden non-terminal using 
+   *  the given string as a base for the name (or "NT$" if null is passed).
+   * @param prefix base name to construct unique name from. 
+   */
+  static non_terminal create_new(String prefix) throws internal_error
+    {
+      if (prefix == null) prefix = "NT$";
+      return new non_terminal(prefix + next_nt++);
+    }
+
+  /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
+
+  /** static routine for creating a new uniquely named hidden non-terminal */
+  static non_terminal create_new() throws internal_error
+    { 
+      return create_new(null); 
+    }
+
+  /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
+
+  /** Compute nullability of all non-terminals. */
+  public static void compute_nullability() throws internal_error
+    {
+      boolean      change = true;
+      non_terminal nt;
+      Enumeration  e;
+      production   prod;
+
+      /* repeat this process until there is no change */
+      while (change)
+	{
+	  /* look for a new change */
+	  change = false;
+
+	  /* consider each non-terminal */
+	  for (e=all(); e.hasMoreElements(); )
+	    {
+	      nt = (non_terminal)e.nextElement();
+
+	      /* only look at things that aren't already marked nullable */
+	      if (!nt.nullable())
+		{
+		  if (nt.looks_nullable())
+		    {
+		      nt._nullable = true;
+		      change = true;
+		    }
+		}
+	    }
+	}
+      
+      /* do one last pass over the productions to finalize all of them */
+      for (e=production.all(); e.hasMoreElements(); )
+	{
+	  prod = (production)e.nextElement();
+	  prod.set_nullable(prod.check_nullable());
+	}
+    }
+
+  /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
+
+  /** Compute first sets for all non-terminals.  This assumes nullability has
+   *  already computed.
+   */
+  public static void compute_first_sets() throws internal_error
+    {
+      boolean      change = true;
+      Enumeration  n;
+      Enumeration  p;
+      non_terminal nt;
+      production   prod;
+      terminal_set prod_first;
+
+      /* repeat this process until we have no change */
+      while (change)
+	{
+	  /* look for a new change */
+	  change = false;
+
+	  /* consider each non-terminal */
+	  for (n = all(); n.hasMoreElements(); )
+	    {
+	      nt = (non_terminal)n.nextElement();
+
+	      /* consider every production of that non terminal */
+	      for (p = nt.productions(); p.hasMoreElements(); )
+		{
+		  prod = (production)p.nextElement();
+
+		  /* get the updated first of that production */
+		  prod_first = prod.check_first_set();
+
+		  /* if this going to add anything, add it */
+		  if (!prod_first.is_subset_of(nt._first_set))
+		    {
+		      change = true;
+		      nt._first_set.add(prod_first);
+		    }
+		}
+	    }
+	}
+    }
+
+  /*-----------------------------------------------------------*/
+  /*--- (Access to) Instance Variables ------------------------*/
+  /*-----------------------------------------------------------*/
+
+  /** Table of all productions with this non terminal on the LHS. */
+  protected Hashtable _productions = new Hashtable(11);
+
+  /** Access to productions with this non terminal on the LHS. */
+  public Enumeration productions() {return _productions.elements();}
+
+  /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
+
+  /** Total number of productions with this non terminal on the LHS. */
+  public int num_productions() {return _productions.size();}
+
+  /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
+
+  /** Add a production to our set of productions. */
+  public void add_production(production prod) throws internal_error
+    {
+      /* catch improper productions */
+      if (prod == null || prod.lhs() == null || prod.lhs().the_symbol() != this)
+	throw new internal_error(
+	  "Attempt to add invalid production to non terminal production table");
+
+      /* add it to the table, keyed with itself */
+      _productions.put(prod,prod);
+    }
+
+  /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
+
+  /** Nullability of this non terminal. */
+  protected boolean _nullable;
+
+  /** Nullability of this non terminal. */
+  public boolean nullable() {return _nullable;}
+
+  /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
+
+  /** First set for this non-terminal. */
+  protected terminal_set _first_set = new terminal_set();
+
+  /** First set for this non-terminal. */
+  public terminal_set first_set() {return _first_set;}
+
+  /*-----------------------------------------------------------*/
+  /*--- General Methods ---------------------------------------*/
+  /*-----------------------------------------------------------*/
+
+  /** Indicate that this symbol is a non-terminal. */
+  public boolean is_non_term() 
+    {
+      return true;
+    }
+
+  /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
+
+  /** Test to see if this non terminal currently looks nullable. */
+  protected boolean looks_nullable() throws internal_error
+    {
+      /* look and see if any of the productions now look nullable */
+      for (Enumeration e = productions(); e.hasMoreElements(); )
+	/* if the production can go to empty, we are nullable */
+	if (((production)e.nextElement()).check_nullable())
+	  return true;
+
+      /* none of the productions can go to empty, so we are not nullable */
+      return false;
+    }
+
+  /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
+
+  /** convert to string */
+  public String toString()
+    {
+      return super.toString() + "[" + index() + "]" + (nullable() ? "*" : "");
+    }
+
+  /*-----------------------------------------------------------*/
+}