Package EDU.purdue.jtb.parser

Class Token

  • All Implemented Interfaces:
    INode, java.io.Serializable
    public class Token
extends java.lang.Object
implements INode, java.io.Serializable
    Represents a JavaCC single token in the grammar and a JTB corresponding node.
    The class holds all the fields and methods generated normally by JavaCC, plus the ones required by JTB.
    If the "-tk" JTB option is used, it also contains an ArrayList of preceding special tokens.
    See Also:
    Serialized Form

    • Field Summary

      Fields 
      Modifier and Type Field Description
      int beginColumn
      The column number of the first character of this token.
      int beginLine
      The line number of the first character of this token.
      int endColumn
      The column number of the last character of this token.
      int endLine
      The line number of the last character of this token.
      java.lang.String image
      The string image of the token.
      int kind
      An integer that describes the kind of this token.
      This numbering system is determined by JavaCCParser,
      and a table of these numbers is stored in the class &l;ParserName>Constants.java.
      Token next
      For a regular token, a reference to the next regular token from the input stream,
      or null if this is the last token from the input stream, or if the token manager
      has not (yet) read a regular token beyond this one.
      Token specialToken
      For a regular token, a reference to the special token just before to this token,
      (without an intervening regular token), or null if there is no such special token.
      java.util.List<Token> specialTokens
      The list of special tokens.

      • Fields inherited from interface EDU.purdue.jtb.parser.syntaxtree.INode

        LS

    • Constructor Summary

      Constructors 
      Constructor Description
      Token()
      No-argument constructor.
      Token​(int ki)
      Constructs a new Token for the specified kind, with a null image.
      Not used in JTB nor JavaCC.
      Token​(int ki, java.lang.String im)
      Constructs a Token with a given kind and image.

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      int accept​(IIntVisitor vis)
      Accepts a IIntVisitor visitor with user return data.
      void accept​(IVoidVisitor vis)
      Accepts a IVoidVisitor visitor} visitor with user return data.
      void addSpecial​(Token s)
      Adds a special token to the special tokens list.
      Token getSpecialAt​(int i)
      Gets the special token in the special tokens list at a given position.
      java.lang.String getSpecials​(java.lang.String spc)
      Returns the string of the special tokens of the current Token, taking in account a given indentation.
      java.lang.Object getValue()
      An optional attribute value of the Token.
      Tokens which are not used as syntactic sugar will often contain meaningful values
      that will be used later on by the compiler or interpreter.
      This attribute value is often different from the image.
      Any subclass of Token that actually wants to return a non-null value
      can override this method as appropriate.
      Not used in JTB.
      static Token newToken​(int ofKind)
      Factory method calling newToken(int, String) with a null image.
      static Token newToken​(int ofKind, java.lang.String image)
      Factory method used by JavaCC to create a new Token
      (which is also a JTB node).
      int numSpecials()  
      java.lang.String toString()  
      void trimSpecials()
      Trims the special tokens list.
      java.lang.String withSpecials​(java.lang.String spc)
      Returns the string of the special tokens and the normal token of the current Token, taking in account a given indentation.
      java.lang.String withSpecials​(java.lang.String spc, java.lang.String var)
      Returns the string of the special tokens and the normal token of the current Token, taking in account a given indentation and a given assignment.

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

    • Field Detail

      • kind

        public int kind
        An integer that describes the kind of this token.
        This numbering system is determined by JavaCCParser,
        and a table of these numbers is stored in the class &l;ParserName>Constants.java.

      • beginLine

        public int beginLine
        The line number of the first character of this token.

      • beginColumn

        public int beginColumn
        The column number of the first character of this token.

      • endLine

        public int endLine
        The line number of the last character of this token.

      • endColumn

        public int endColumn
        The column number of the last character of this token.

      • image

        public java.lang.String image
        The string image of the token.

      • next

        public Token next
        For a regular token, a reference to the next regular token from the input stream,
        or null if this is the last token from the input stream, or if the token manager
        has not (yet) read a regular token beyond this one.

        For a special token, a reference to the special token that just after it
        (without an intervening regular token) if it exists, or null otherwise.

      • specialToken

        public Token specialToken
        For a regular token, a reference to the special token just before to this token,
        (without an intervening regular token), or null if there is no such special token.

        For a special token, a reference to the special token just after it
        (without an intervening regular token) if it exists, or null otherwise.

      • specialTokens

        public java.util.List<Token> specialTokens
        The list of special tokens. TODO add explanation

    • Constructor Detail

      • Token

        public Token()
        No-argument constructor.

      • Token

        public Token​(int ki)
        Constructs a new Token for the specified kind, with a null image.
        Not used in JTB nor JavaCC.
        Parameters:
        ki - - the token kind

      • Token

        public Token​(int ki,
             java.lang.String im)
        Constructs a Token with a given kind and image.
        Parameters:
        ki - - the token kind
        im - - the token image

    • Method Detail

      • getValue

        public java.lang.Object getValue()
        An optional attribute value of the Token.
        Tokens which are not used as syntactic sugar will often contain meaningful values
        that will be used later on by the compiler or interpreter.
        This attribute value is often different from the image.
        Any subclass of Token that actually wants to return a non-null value
        can override this method as appropriate.
        Not used in JTB.
        Returns:
        a value

      • newToken

        public static Token newToken​(int ofKind,
                             java.lang.String image)
        Factory method used by JavaCC to create a new Token
        (which is also a JTB node). By default returns a new Token object. You can override it to create and return subclass objects
        based on the value of ofKind.
        Simply add the cases to the switch for all those special cases.
        For example, if you have a subclass of Token called IDToken
        that you want to create if ofKind is ID, simply add something like:
        case MyParserConstants.ID : return new IDToken(ofKind, image);
        to the following switch statement.
        Then you can cast matchedToken variable to the appropriate type
        and use it in your lexical actions.
        Parameters:
        ofKind - - the token kind
        image - - the token image
        Returns:
        a new Token

      • newToken

        public static Token newToken​(int ofKind)
        Factory method calling newToken(int, String) with a null image.
        Parameters:
        ofKind - - the token kind
        Returns:
        a new Token

      • toString

        public java.lang.String toString()
        Overrides:
        toString in class java.lang.Object
        Returns:
        the token image

      • getSpecialAt

        public Token getSpecialAt​(int i)
        Gets the special token in the special tokens list at a given position.
        Parameters:
        i - - the special token's position
        Returns:
        the special token

      • numSpecials

        public int numSpecials()
        Returns:
        the number of special tokens

      • addSpecial

        public void addSpecial​(Token s)
        Adds a special token to the special tokens list.
        Parameters:
        s - - the special token to add

      • trimSpecials

        public void trimSpecials()
        Trims the special tokens list.

      • getSpecials

        public java.lang.String getSpecials​(java.lang.String spc)
        Returns the string of the special tokens of the current Token, taking in account a given indentation.
        Parameters:
        spc - - the indentation
        Returns:
        the string representing the special tokens list

      • withSpecials

        public java.lang.String withSpecials​(java.lang.String spc)
        Returns the string of the special tokens and the normal token of the current Token, taking in account a given indentation.
        Parameters:
        spc - - the indentation
        Returns:
        the string representing the special tokens list and the token

      • withSpecials

        public java.lang.String withSpecials​(java.lang.String spc,
                                     java.lang.String var)
        Returns the string of the special tokens and the normal token of the current Token, taking in account a given indentation and a given assignment.
        Parameters:
        spc - - the indentation
        var - - the variable assignment to be inserted
        Returns:
        the string representing the special tokens list and the token

      • accept

        public int accept​(IIntVisitor vis)
        Accepts a IIntVisitor visitor with user return data.
        Specified by:
        accept in interface INode
        Parameters:
        vis - - the visitor
        Returns:
        the user Return data

      • accept

        public void accept​(IVoidVisitor vis)
        Accepts a IVoidVisitor visitor} visitor with user return data.
        Specified by:
        accept in interface INode
        Parameters:
        vis - - the visitor