Package icyllis.arc3d.compiler.lex

Class NFA

java.lang.Object

icyllis.arc3d.compiler.lex.NFA

public class NFA
extends Object

A nondeterministic finite automaton for matching regular expressions. The NFA is initialized with a number of regular expressions, and then matches a string against all of them simultaneously.

Constructor Summary

Constructors

Constructor	Description
NFA()

Method Summary

Modifier and Type	Method	Description
int	add(NFAState state)	Adds a new state to the NFA, returning its index.
void	add(RegexNode node)	Adds a new regular expression to the set of expressions matched by this automaton.
NFAState	get(int index)	Gets a NFA state from its index.
int	match(String s)	Matches a string against all of the regexes added to this NFA.
it.unimi.dsi.fastutil.ints.IntList	replace(int index, it.unimi.dsi.fastutil.ints.IntList shadow)	When we transition to the NFA state which is given by index, we instead transition to all of the shadow states.

Methods inherited from class java.lang.Object

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

Constructor Details

NFA

public NFA()

Method Details

add

public void add(@Nonnull
 RegexNode node)

Adds a new regular expression to the set of expressions matched by this automaton.

add

public int add(NFAState state)

Adds a new state to the NFA, returning its index.

get

public NFAState get(int index)

Gets a NFA state from its index.

replace

public it.unimi.dsi.fastutil.ints.IntList replace(int index,
 it.unimi.dsi.fastutil.ints.IntList shadow)

When we transition to the NFA state which is given by index, we instead transition to all of the shadow states.

match

public int match(@Nonnull
 String s)

Matches a string against all of the regexes added to this NFA. Returns the index of the first (in addRegex order) matching expression, or -1 if no match. This is relatively slow and used only for debugging purposes; the NFA should be converted to a DFA before actual use.