oops.parser
Interface Scanner


public interface Scanner

describes what a scanner for an oops-generated parser must do.


Method Summary
 boolean advance()
          move on to next token.
 boolean atEnd()
           
 java.lang.Object node()
           
 void scan(java.io.Reader in, Parser parser)
          initialize, read one symbol ahead.
 Set tokenSet()
           
 

Method Detail

scan

public void scan(java.io.Reader in,
                 Parser parser)
          throws java.io.IOException
initialize, read one symbol ahead.
Parameters:
parser - is used to screen symbols.

advance

public boolean advance()
                throws java.io.IOException
move on to next token.
Returns:
false if atEnd() becomes true.

atEnd

public boolean atEnd()
Returns:
true if positioned beyond tokens.

tokenSet

public Set tokenSet()
Returns:
single-element lookahead set, null for unidentifiable token.

node

public java.lang.Object node()
Returns:
node corresponding to token.