Package jflex.core

Class RegExp

java.lang.Object

jflex.core.RegExp

Direct Known Subclasses:

RegExp1, RegExp2

public class RegExp
extends Object

Stores a regular expression of rules section in a JFlex-specification.

This base class has no content other than its type.

Version:

JFlex 1.8.1

Author:

Gerwin Klein

Constructor Summary

Constructors

Constructor	Description
RegExp(int type)	Create a new regular expression of the specified type.

Method Summary

Modifier and Type	Method	Description
static RegExp	anyChar()	Returns a regexp that matches any character: [^]
static RegExp1	checkPrimClass(RegExp r)	Confirms that the parameter is a RegExp1 of type sym.PRIMCLASS.
boolean	isCharClass()	Find out if this regexp is a char class or equivalent to one.
void	makeCCLs(CharClasses c, boolean caseless)	Make character class partitions based on the classes mentioned in this regexp.
RegExp	normalise(Macros m)	Normalise the regular expression to eliminate macro use (expand them), and compound character class expression (compute their content).
static IntCharSet	performClassOp(int op, IntCharSet l, IntCharSet r, RegExp ctxt)	Performs the given set operation on the two IntCharSet parameters.
String	print(String tab)	Returns a String-representation of this regular expression with the specified indentation.
RegExp	resolveTilde()	Recursively convert tilde (upto) expressions into negation and star.
RegExp	rev()	Creates a new regexp that matches the reverse text of this one.
int	size(Macros macros)	The approximate number of NFA states this expression will need (only works correctly after macro expansion and without negation)
String	toString()
String	typeName()	String representation of the type of this regular expression.

Methods inherited from class java.lang.Object

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

Constructor Detail

RegExp

public RegExp(int type)

Create a new regular expression of the specified type.

Parameters:

type - a value from the cup generated class sym.

Method Detail

print

public String print(String tab)

Returns a String-representation of this regular expression with the specified indentation.

Parameters:

tab - a String that should contain only space characters and that is inserted in front of standard String-representation pf this object.

Returns:

a String object.

toString

public String toString()

Overrides:

toString in class Object

typeName

public String typeName()

String representation of the type of this regular expression.

isCharClass

public boolean isCharClass()

Find out if this regexp is a char class or equivalent to one.

Returns:

true if the regexp is equivalent to a char class.

size

public int size(Macros macros)

The approximate number of NFA states this expression will need (only works correctly after macro expansion and without negation)

Parameters:

macros - macro table for expansion

Returns:

a int.

resolveTilde

public final RegExp resolveTilde()

Recursively convert tilde (upto) expressions into negation and star.

Returns:

new RegExp equivalent to the current one, but without upto expressions.

anyChar

public static RegExp anyChar()

Returns a regexp that matches any character: [^]

Returns:

the regexp for [^]

checkPrimClass

public static RegExp1 checkPrimClass(RegExp r)

Confirms that the parameter is a RegExp1 of type sym.PRIMCLASS.

Parameters:

r - the RegExp to check

Returns:

r cast to RegExp1

Throws:

CharClassException - if r is not a RegExp1 or of type sym.PRIMCLASS.

performClassOp

public static IntCharSet performClassOp(int op,
                                        IntCharSet l,
                                        IntCharSet r,
                                        RegExp ctxt)

Performs the given set operation on the two IntCharSet parameters.

Parameters:

op - the operation to perform (as @{link sym} constant)

l - the left operator of the expression

r - the right operator of the expression

ctxt - the regular expression containing the provided operator

Returns:

a new IntCharSet

Throws:

RegExpException - for ctxt if the operator is not supported

normalise

public final RegExp normalise(Macros m)

Normalise the regular expression to eliminate macro use (expand them), and compound character class expression (compute their content).

Returns:

a regexp that contains only IntCharSet char classes and no sym.MACROUSE.

makeCCLs

public final void makeCCLs(CharClasses c,
                           boolean caseless)

Make character class partitions based on the classes mentioned in this regexp.

Assumption: regexp is normalised.

rev

public final RegExp rev()

Creates a new regexp that matches the reverse text of this one.

Returns:

the reverse regexp