1 files changed, 93 insertions, 0 deletions
diff --git a/src/syntaxParser/java_cup/lalr_transition.java b/src/syntaxParser/java_cup/lalr_transition.java
new file mode 100644
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--- /dev/null
+++ b/src/syntaxParser/java_cup/lalr_transition.java
@@ -0,0 +1,93 @@
+package java_cup;
+
+/** This class represents a transition in an LALR viable prefix recognition 
+ *  machine.  Transitions can be under terminals for non-terminals.  They are
+ *  internally linked together into singly linked lists containing all the 
+ *  transitions out of a single state via the _next field.
+ *
+ * @see     java_cup.lalr_state
+ * @version last updated: 11/25/95
+ * @author  Scott Hudson
+ *
+ */
+public class lalr_transition {
+
+  /*-----------------------------------------------------------*/
+  /*--- Constructor(s) ----------------------------------------*/
+  /*-----------------------------------------------------------*/
+
+  /** Full constructor.
+   * @param on_sym  symbol we are transitioning on.
+   * @param to_st   state we transition to.
+   * @param nxt     next transition in linked list.
+   */
+  public lalr_transition(symbol on_sym, lalr_state to_st, lalr_transition nxt)
+    throws internal_error
+    {
+      /* sanity checks */
+      if (on_sym == null)
+	throw new internal_error("Attempt to create transition on null symbol");
+      if (to_st == null)
+	throw new internal_error("Attempt to create transition to null state");
+
+      /* initialize */
+      _on_symbol = on_sym;
+      _to_state  = to_st;
+      _next      = nxt;
+    }
+
+  /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
+
+  /** Constructor with null next. 
+   * @param on_sym  symbol we are transitioning on.
+   * @param to_st   state we transition to.
+   */
+  public lalr_transition(symbol on_sym, lalr_state to_st) throws internal_error
+    {
+      this(on_sym, to_st, null);
+    }
+
+  /*-----------------------------------------------------------*/
+  /*--- (Access to) Instance Variables ------------------------*/
+  /*-----------------------------------------------------------*/
+
+  /** The symbol we make the transition on. */
+  protected symbol _on_symbol;
+
+  /** The symbol we make the transition on. */
+  public symbol on_symbol() {return _on_symbol;}
+
+  /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
+
+  /** The state we transition to. */
+  protected lalr_state _to_state;
+
+  /** The state we transition to. */
+  public lalr_state to_state() {return _to_state;}
+
+  /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
+
+  /** Next transition in linked list of transitions out of a state */
+  protected lalr_transition _next;
+
+  /** Next transition in linked list of transitions out of a state */
+  public lalr_transition next() {return _next;}
+
+  /*-----------------------------------------------------------*/
+  /*--- General Methods ---------------------------------------*/
+  /*-----------------------------------------------------------*/
+
+  /** Convert to a string. */
+  public String toString()
+    {
+      String result;
+
+      result = "transition on " + on_symbol().name() + " to state [";
+      result += _to_state.index();
+      result += "]";
+
+      return result;
+    }
+
+  /*-----------------------------------------------------------*/
+}