1 2 package java_cup.runtime; 3 4 /** This class represents a (terminal or non-terminal) symbol that, among 5 * other things can be placed on the parse stack. Symbols are used to 6 * keep track of state on the parse stack. The symbol currently on top 7 * of the stack contains the current state in the parse_state field. 8 * In addition to the parse_state field, symbols also maintain a record 9 * of the symbol number that they represent in the sym field. Finally, 10 * symbols are used contain to any attributes used by semantic action (this 11 * is done via fields added in subclasses -- see for example, int_token and 12 * str_token). 13 * 14 * @see java_cup.runtime.token 15 * @see java_cup.runtime.int_token 16 * @see java_cup.runtime.str_token 17 * @version last updated: 11/25/95 18 * @author Scott Hudson 19 */ 20 21 public class symbol { 22 23 /** Full constructor. */ 24 public symbol(int sym_num, int state) 25 { 26 sym = sym_num; 27 parse_state = state; 28 } 29 30 /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/ 31 32 /** Constructor without a known state. */ 33 public symbol(int sym_num) 34 { 35 this(sym_num, -1); 36 } 37 38 /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/ 39 40 /** The symbol number of the terminal or non terminal being represented */ 41 public int sym; 42 43 /*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/ 44 45 /** The parse state to be recorded on the parse stack with this symbol. 46 * This field is for the convenience of the parser and shouldn't be 47 * modified except by the parser. 48 */ 49 public int parse_state; 50 }; 51
