PerCederberg.Grammatica.Runtime.RE
Class AlternativeElement

ICloneable
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   +--Element
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         +--AlternativeElement

internal class AlternativeElement

extends Element

A regular expression alternative element. This element matches the longest alternative element.

AlternativeElement

public AlternativeElement( Element first, Element second );

Creates a new alternative element.

Parameters:

first - the first alternative

second - the second alternative

Clone

public override 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 override 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 longest matching string, or -1 if no match was found

Throws:

IOException - if an I/O error occurred

PrintTo

public override 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