Class SExpressionParser

java.lang.Object
  |
  +--SExpressionParser

public class SExpressionParser

extends java.lang.Object

Parses S-Expressions. To do so, call SExpressionParser.parse(InputStream).

For example,

  (
    (PROGRAM            1)
    (IDENT     P        3)
    (SEMICOLON          6)
  )

  

parses into the following contents:

  java.util.Vector {
    java.util.Vector { SExprToken(kind=SExprToken.ATOM,   value="PROGRAM"),
                       SExprToken(kind=SExprToken.INTLIT, value="1")},
    java.util.Vector { SExprToken(kind=SExprToken.ATOM,   value="IDENT"),
                       SExprToken(kind=SExprToken.ATOM,   value="P"),
                       SExprToken(kind=SExprToken.INTLIT, value="3")},
    java.util.Vector { SExprToken(kind=SExprToken.ATOM,   value="SEMICOLON"),
                       SExprToken(kind=SExprToken.INTLIT, value="6")}
  }

  

So what you probably think of as one "token" from the lexer is actually a Vector of SExprTokens. You can pull this Vector apart and put it into your own objects, so you don't have to deal with all the vector-of- vectors overhead. The reason it is written this way is because it has to be general enough that it works for later phases of the compiler as well.

Code example:

  Vector tokens = SExpressionParser.parse(new FileInputStream("somefile.dat"));
  for (int i = 0; i < tokens.size(); i++)
    System.out.println("token: " + tokens.get(i));


  

Method Summary

static java.util.Vector

parse(java.io.InputStream in) Call this method to parse a stream of characters into an SExpression, modeled by a vector of vectors.

Methods inherited from class java.lang.Object

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

Method Detail

parse

public static java.util.Vector parse(java.io.InputStream in)
                              throws java.io.IOException

Call this method to parse a stream of characters into an SExpression, modeled by a vector of vectors.