Checking in stuff

[IRC.git] / Robust / cup / java_cup / shift_action.java

diff --git a/Robust/cup/java_cup/shift_action.java b/Robust/cup/java_cup/shift_action.java
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+++ b/Robust/cup/java_cup/shift_action.java
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+
+package java_cup;
+
+/** This class represents a shift action within the parse table. 
+ *  The action simply stores the state that it shifts to and responds 
+ *  to queries about its type.
+ *
+ * @version last updated: 11/25/95
+ * @author  Scott Hudson
+ */
+public class shift_action extends parse_action {
+
+  /*-----------------------------------------------------------*/
+  /*--- Constructor(s) ----------------------------------------*/
+  /*-----------------------------------------------------------*/
+
+  /** Simple constructor. 
+   * @param shft_to the state that this action shifts to.
+   */
+  public shift_action(lalr_state shft_to) throws internal_error
+    {
+      /* sanity check */
+      if (shft_to == null)
+       throw new internal_error(
+         "Attempt to create a shift_action to a null state");
+
+      _shift_to = shft_to;
+    }
+
+  /*-----------------------------------------------------------*/
+  /*--- (Access to) Instance Variables ------------------------*/
+  /*-----------------------------------------------------------*/
+
+  /** The state we shift to. */
+  protected lalr_state _shift_to;
+
+  /** The state we shift to. */
+  public lalr_state shift_to() {return _shift_to;}
+
+  /*-----------------------------------------------------------*/
+  /*--- General Methods ---------------------------------------*/
+  /*-----------------------------------------------------------*/
+
+  /** Quick access to type of action. */
+  public int kind() {return SHIFT;}
+
+  /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
+
+  /** Equality test. */
+  public boolean equals(shift_action other)
+    {
+      return other != null && other.shift_to() == shift_to();
+    }
+
+  /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
+
+  /** Generic equality test. */
+  public boolean equals(Object other)
+    {
+      if (other instanceof shift_action)
+       return equals((shift_action)other);
+      else
+       return false;
+    }
+
+  /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
+
+  /** Compute a hash code. */
+  public int hashCode()
+    {
+      /* use the hash code of the state we are shifting to */
+      return shift_to().hashCode();
+    }
+
+  /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
+
+  /** Convert to a string. */
+  public String toString() {return "SHIFT(to state " + shift_to().index() + ")";}
+
+  /*-----------------------------------------------------------*/
+
+}