Package java_cup

Class symbol

  • Direct Known Subclasses:
    non_terminal, terminal

    public abstract class symbol
    extends java.lang.Object
    This abstract class serves as the base class for grammar symbols (i.e., both terminals and non-terminals). Each symbol has a name string, and a string giving the type of object that the symbol will be represented by on the runtime parse stack. In addition, each symbol maintains a use count in order to detect symbols that are declared but never used, and an index number that indicates where it appears in parse tables (index numbers are unique within terminals or non terminals, but not across both).
    See Also:
    terminal, non_terminal
    • Field Summary

      Fields 
      Modifier and Type Field Description
      protected int _index
      Index of this symbol (terminal or non terminal) in the parse tables.
      protected java.lang.String _name
      String for the human readable name of the symbol.
      protected java.lang.String _stack_type
      String for the type of object used for the symbol on the parse stack.
      protected int _use_count
      Count of how many times the symbol appears in productions.
    • Constructor Summary

      Constructors 
      Constructor Description
      symbol​(java.lang.String nm)
      Constructor with default type.
      symbol​(java.lang.String nm, java.lang.String tp)
      Full constructor.
    • Method Summary

      All Methods Instance Methods Abstract Methods Concrete Methods 
      Modifier and Type Method Description
      int index()
      Index of this symbol (terminal or non terminal) in the parse tables.
      abstract boolean is_non_term()
      Indicate if this is a non-terminal.
      java.lang.String name()
      String for the human readable name of the symbol.
      void note_use()
      Increment the use count.
      java.lang.String stack_type()
      String for the type of object used for the symbol on the parse stack.
      java.lang.String toString()
      Convert to a string.
      int use_count()
      Count of how many times the symbol appears in productions.
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
    • Field Detail

      • _name

        protected java.lang.String _name
        String for the human readable name of the symbol.
      • _stack_type

        protected java.lang.String _stack_type
        String for the type of object used for the symbol on the parse stack.
      • _use_count

        protected int _use_count
        Count of how many times the symbol appears in productions.
      • _index

        protected int _index
        Index of this symbol (terminal or non terminal) in the parse tables. Note: indexes are unique among terminals and unique among non terminals, however, a terminal may have the same index as a non-terminal, etc.
    • Constructor Detail

      • symbol

        public symbol​(java.lang.String nm,
                      java.lang.String tp)
        Full constructor.
        Parameters:
        nm - the name of the symbol.
        tp - a string with the type name.
      • symbol

        public symbol​(java.lang.String nm)
        Constructor with default type.
        Parameters:
        nm - the name of the symbol.
    • Method Detail

      • name

        public java.lang.String name()
        String for the human readable name of the symbol.
      • stack_type

        public java.lang.String stack_type()
        String for the type of object used for the symbol on the parse stack.
      • use_count

        public int use_count()
        Count of how many times the symbol appears in productions.
      • note_use

        public void note_use()
        Increment the use count.
      • index

        public int index()
        Index of this symbol (terminal or non terminal) in the parse tables. Note: indexes are unique among terminals and unique among non terminals, however, a terminal may have the same index as a non-terminal, etc.
      • is_non_term

        public abstract boolean is_non_term()
        Indicate if this is a non-terminal. Here in the base class we don't know, so this is abstract.
      • toString

        public java.lang.String toString()
        Convert to a string.
        Overrides:
        toString in class java.lang.Object