ch.akuhn.fame.parser
Class Scanner

java.lang.Object
  ch.akuhn.fame.parser.Scanner

All Implemented Interfaces:

Iterable<Token>, Iterator<Token>

public class Scanner
extends Object
implements Iterator<Token>, Iterable<Token>

Breaks input-stream into tokens. Accepts the following grammar

Tokens

 OPEN       ::= "("
 CLOSE      ::= ")"
 ID         ::= "id:"
 REF        ::= "ref:"
 KEYWORD    ::= "@" NamePart
 NAME       ::= NamePart ( "." NamePart )*
 STRING     ::= ( "'" [ˆ']* "'" )+
 BOOLEAN    ::= "true" | "false"
 UNDEFINED  ::= "nil"
 NUMBER     ::= "-"? Digit+ ( "." Digit+ )? ( "e"  ( "-"? Digit+ ))?
 

Terminals and Intermediates

 NamePart   ::= Letter ( Letter | Digit )*
 Digit      ::= [0-9]
 Letter     ::= [a-zA-Z_]
 

Whitespace

 Whitespace ::= \s+
 Comment    ::= "\"" [ˆ"]* "\""
 

In order to provide more user friendly error messages, this implementation imposed the following constraint upon the sequence of tokens: Name must be followed by whitespace; String, Undefined, Boolean, and Number must be followed by Open, Close or whitespace.

If the input source is in Smalltalk compatibility mode, the grammar is extended as follows

 Unlimited ::= "*" 
 Keyword ::= ... | Letter+ ":"
 

Constructor Summary

Scanner(CharSequence string)

Scanner(InputSource in)

Method Summary

boolean	hasNext()
Iterator<Token>	iterator()
Token	next()
Token	nextOrEOF()
Position	pos()
void	remove()

Methods inherited from class java.lang.Object

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

Constructor Detail

Scanner

public Scanner(CharSequence string)

Scanner

public Scanner(InputSource in)

Method Detail

hasNext

public boolean hasNext()

Specified by:

hasNext in interface Iterator<Token>

iterator

public Iterator<Token> iterator()

Specified by:

iterator in interface Iterable<Token>

next

public Token next()

Specified by:

next in interface Iterator<Token>

nextOrEOF

public Token nextOrEOF()

pos

public final Position pos()

remove

public void remove()

Specified by:

remove in interface Iterator<Token>