Initial commit

1 files changed, 105 insertions, 0 deletions

diff --git a/src/java_cup/runtime/Symbol.java b/src/java_cup/runtime/Symbol.java
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+++ b/src/java_cup/runtime/Symbol.java
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+package java_cup.runtime;
+
+/**
+ * Defines the Symbol class, which is used to represent all terminals
+ * and nonterminals while parsing.  The lexer should pass CUP Symbols 
+ * and CUP returns a Symbol.
+ *
+ * @version last updated: 7/3/96
+ * @author  Frank Flannery
+ */
+
+/* ****************************************************************
+  Class Symbol
+  what the parser expects to receive from the lexer. 
+  the token is identified as follows:
+  sym:    the symbol type
+  parse_state: the parse state.
+  value:  is the lexical value of type Object
+  left :  is the left position in the original input file
+  right:  is the right position in the original input file
+******************************************************************/
+
+public class Symbol {
+
+/*******************************
+  Constructor for l,r values
+ *******************************/
+
+  public Symbol(int id, int l, int r, Object o) {
+    this(id);
+    left = l;
+    right = r;
+    value = o;
+  }
+
+/*******************************
+  Constructor for no l,r values
+********************************/
+
+  public Symbol(int id, Object o) {
+    this(id, -1, -1, o);
+  }
+
+/*****************************
+  Constructor for no value
+  ***************************/
+
+  public Symbol(int id, int l, int r) {
+    this(id, l, r, null);
+  }
+
+/***********************************
+  Constructor for no value or l,r
+***********************************/
+
+  public Symbol(int sym_num) {
+    this(sym_num, -1);
+    left = -1;
+    right = -1;
+    value = null;
+  }
+
+/***********************************
+  Constructor to give a start state
+***********************************/
+  Symbol(int sym_num, int state)
+    {
+      sym = sym_num;
+      parse_state = state;
+    }
+
+/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
+
+  /** The symbol number of the terminal or non terminal being represented */
+  public int sym;
+
+  /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
+
+  /** The parse state to be recorded on the parse stack with this symbol.
+   *  This field is for the convenience of the parser and shouldn't be 
+   *  modified except by the parser. 
+   */
+  public int parse_state;
+  /** This allows us to catch some errors caused by scanners recycling
+   *  symbols.  For the use of the parser only. [CSA, 23-Jul-1999] */
+  boolean used_by_parser = false;
+
+/*******************************
+  The data passed to parser
+ *******************************/
+
+  public int left, right;
+  public Object value;
+
+  /*****************************
+    Printing this token out. (Override for pretty-print).
+    ****************************/
+  public String toString() { return "#"+sym; }
+}
+
+
+
+
+
+