| Methods Summary |
|---|
| public abstract char | BeginToken()Returns the next character that marks the beginning of the next token.
All characters must remain in the buffer between two successive calls
to this method to implement backup correctly.
|
| public abstract void | Done()The lexer calls this function to indicate that it is done with the stream
and hence implementations can free any resources held by this class.
Again, the body of this function can be just empty and it will not
affect the lexer's operation.
|
| public abstract java.lang.String | GetImage()Returns a string made up of characters from the marked token beginning
to the current buffer position. Implementations have the choice of returning
anything that they want to. For example, for efficiency, one might decide
to just return null, which is a valid implementation.
|
| public abstract char[] | GetSuffix(int len)Returns an array of characters that make up the suffix of length 'len' for
the currently matched token. This is used to build up the matched string
for use in actions in the case of MORE. A simple and inefficient
implementation of this is as follows :
{
String t = GetImage();
return t.substring(t.length() - len, t.length()).toCharArray();
}
|
| public abstract void | backup(int amount)Backs up the input stream by amount steps. Lexer calls this method if it
had already read some characters, but could not use them to match a
(longer) token. So, they will be used again as the prefix of the next
token and it is the implemetation's responsibility to do this right.
|
| public abstract int | getBeginColumn()Returns the column number of the first character for current token (being
matched after the last call to BeginTOken).
|
| public abstract int | getBeginLine()Returns the line number of the first character for current token (being
matched after the last call to BeginTOken).
|
| public abstract int | getColumn()Returns the column position of the character last read.
|
| public abstract int | getEndColumn()Returns the column number of the last character for current token (being
matched after the last call to BeginTOken).
|
| public abstract int | getEndLine()Returns the line number of the last character for current token (being
matched after the last call to BeginTOken).
|
| public abstract int | getLine()Returns the line number of the character last read.
|
| public abstract char | readChar()Returns the next character from the selected input. The method
of selecting the input is the responsibility of the class
implementing this interface. Can throw any java.io.IOException.
|
