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// PLEASE DO NOT EDIT WITHOUT THE EXPLICIT CONSENT OF THE AUTHOR! \\
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package hlt.language.util;
/**
* This class is a concrete implementation of the abstract class RegExpOne to represent a "plussed"
* regular expression (i.e., one or more).
*
* @version Last modified on Thu Mar 31 15:56:11 2016 by hak
* @author Hassan Aït-Kaci
* @copyright © Hassan Aït-Kaci
*/
public class RegExpPlus extends RegExpOne
{
/**
* Constructs a RegExpPlus with the specified
* RegExp.
*/
public RegExpPlus (RegExp arg)
{
super(arg);
}
public final int type ()
{
return PLUS_EXP;
}
public final RegExp shallowCopy ()
{
return plus(_arg);
}
public final RegExp deepCopy ()
{
return plus(_arg.deepCopy());
}
/**
* This returns this RegExpPlus's
* normal form according to the following rewrite rules:
*
*
*
* -
*
* [PL:E]
*
*
*
* ()+
*
* →
*
*
* ()
*
*
*
*
-
*
* [PL:O]
*
*
*
* X?+
*
* →
*
*
* X\*
*
*
*
*
-
*
* [PL:P]
*
*
*
* X++
*
* →
*
*
* X+
*
*
*
*
-
*
* [PL:S]
*
*
*
* X\*+
*
* →
*
*
* X\*
*
*
*
*
*
* Note that there are no rules for X^n+ nor X_n^m+
* since such forms cannot be further normalized.
*/
public void normalize ()
{
String rule = null;
RegExp arg = arg();
switch (arg.type())
{
case EMPTY_EXP:
rule = "[PL:E] ()+ --> ()";
_normalForm = RegExpSymbol.EMPTY;
break;
case OPTION_EXP:
rule = "[PL:O] X?+ --> X*";
_normalForm = star(arg.arg());
break;
case PLUS_EXP:
rule = "[PL:P] X++ --> X+";
_normalForm = arg;
break;
case STAR_EXP:
rule = "[PL:S] X*+ --> X*";
_normalForm = arg;
break;
}
traceRule(rule);
checkNormalForm();
}
/**
* Returns a printable form for this RegExpPlus.
*/
public final String toString ()
{
if (_arg.isBinary())
return "("+_arg+")+";
return _arg+"+";
}
public final String toNormalString ()
{
if (!inNormalForm())
return _normalForm.toNormalString();
if (_arg.isBinary())
return "("+_arg.toNormalString()+")+";
return _arg.toNormalString()+"+";
}
}