Package com.yahoo.prelude.semantics.parser

Class Token

java.lang.Object
com.yahoo.prelude.semantics.parser.Token
All Implemented Interfaces:
Serializable
public class Token extends Object implements Serializable
Describes the input token stream.
See Also:

  • 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.
    String
    image
    The string image of the token.
    int
    kind
    An integer that describes the kind of this token.
    Token
    next
    A reference to the next regular (non-special) token from the input stream.
    Token
    specialToken
    This field is used to access special tokens that occur prior to this token, but after the immediately preceding regular (non-special) token.

  • Constructor Summary

    Constructors
    Constructor
    Description
    Token()
    No-argument constructor
    Token(int nKind)
    Constructs a new token for the specified Image.
    Token(int nKind, String sImage)
    Constructs a new token for the specified Image and Kind.

  • Method Summary

    Modifier and Type
    Method
    Description
    Object
    getValue()
    An optional attribute value of the Token.
    static Token
    newToken(int ofKind)
     
    static Token
    newToken(int ofKind, String image)
    Returns a new Token object, by default.
    String
    toString()
    Returns the image.

    Methods inherited from class java.lang.Object

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

  • Field Details

    • 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 file ...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 String image
      The string image of the token.

    • next

      public Token next
      A reference to the next regular (non-special) token from the input stream. If this is the last token from the input stream, or if the token manager has not read tokens beyond this one, this field is set to null. This is true only if this token is also a regular token. Otherwise, see below for a description of the contents of this field.

    • specialToken

      public Token specialToken
      This field is used to access special tokens that occur prior to this token, but after the immediately preceding regular (non-special) token. If there are no such special tokens, this field is set to null. When there are more than one such special token, this field refers to the last of these special tokens, which in turn refers to the next previous special token through its specialToken field, and so on until the first special token (whose specialToken field is null). The next fields of special tokens refer to other special tokens that immediately follow it (without an intervening regular token). If there is no such token, this field is null.

  • Constructor Details

    • Token

      public Token()
      No-argument constructor

    • Token

      public Token(int nKind)
      Constructs a new token for the specified Image.

    • Token

      public Token(int nKind, String sImage)
      Constructs a new token for the specified Image and Kind.

  • Method Details

    • getValue

      public 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.

    • toString

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

    • newToken

      public static Token newToken(int ofKind, String image)
      Returns a new Token object, by default. However, if you want, you can 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 sit in your lexical actions.

    • newToken

      public static Token newToken(int ofKind)