org.metasyntactic.math.automata
Class LookAheadParseTable

java.lang.Object
  |
  +--org.metasyntactic.math.automata.LRParseTable
        |
        +--org.metasyntactic.math.automata.LookAheadParseTable

All Implemented Interfaces:

FiniteAutomata, java.io.Serializable

public class LookAheadParseTable

extends LRParseTable

The LALR method is often used in practise because the tables obtained by it are considerably smaller than the CanonicalParseTable, yet most common syntactic constructs of programming languages can be expressed conveniently by an LALR grammar. The same is almost true for SLR grammars, but there are a few constructs that connot be conveniently handled by SLR techniques.

For a comparison of parse size, the SLR and LALR tabes for a grammar always have the same number of states, and tis number is typically several hundred states for a language like Pascal. The CanonicalParseTable would typically have several thousand states for the same size language. Thus, it is more economical to construct SLR and LALR tables than the CanonicalParseTable.

See Also:

Serialized Form

Nested Class Summary

Nested classes inherited from class org.metasyntactic.math.automata.LRParseTable

LRParseTable.Accept, LRParseTable.Action, LRParseTable.Error, LRParseTable.Reduce, LRParseTable.Shift, LRParseTable.StateAndSymbol

Field Summary

Fields inherited from class org.metasyntactic.math.automata.LRParseTable

actions, characterClasses, gotos, nonterminals, productionToNum, startState, states, terminals

Constructor Summary

LookAheadParseTable(ContextFreeGrammar G)

Method Summary

protected java.util.Set	getLookAhead(java.util.Set q, Production prod)
protected java.util.Set	go(java.util.Set p, java.util.List w)
static void	main(java.lang.String[] args)

Methods inherited from class org.metasyntactic.math.automata.LRParseTable

accept, accept, addAccept, addAcceptListener, addError, addErrorListener, addGoto, addProduction, addReduce, addReduceListener, addShift, addShiftListener, addState, getLargeTable, newToString, removeAcceptListener, removeErrorListener, removeReduceListener, removeShiftListener, setStartState, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

LookAheadParseTable

public LookAheadParseTable(ContextFreeGrammar G)
                    throws ParseTableConflict

Method Detail

getLookAhead

protected java.util.Set getLookAhead(java.util.Set q,
                                     Production prod)

go

protected java.util.Set go(java.util.Set p,
                           java.util.List w)

main

public static void main(java.lang.String[] args)