PerCederberg.Grammatica.Runtime.RE
Class Element

ICloneable
   |
   +--Element

Direct Known Subclasses:

AlternativeElement, CharacterSetElement, CombineElement, RepeatElement, StringElement

internal abstract class Element

extends ICloneable

A regular expression element. This is the common base class for all regular expression elements, i.e. the parts of the regular expression.

Clone

public abstract object Clone();

Creates a copy of this element. The copy will be an instance of the same class matching the same strings. Copies of elements are necessary to allow elements to cache intermediate results while matching strings without interfering with other threads.

Returns:

a copy of this element

Match

public abstract int Match( Matcher m, ReaderBuffer buffer, int start, int skip );

Returns the length of a matching string starting at the specified position. The number of matches to skip can also be specified, but numbers higher than zero (0) cause a failed match for any element that doesn't attempt to combine other elements.

Parameters:

m - the matcher being used

buffer - the input character buffer to match

start - the starting position

skip - the number of matches to skip

Returns:

the length of the matching string, or -1 if no match was found

Throws:

IOException - if an I/O error occurred

PrintTo

public abstract void PrintTo( TextWriter output, string indent );

Prints this element to the specified output stream.

Parameters:

output - the output stream to use

indent - the current indentation