nl_tokens: Compute the string of a given regular expression capture .
pl_tokens: function CaptureString ( string , lastCaptureInfo , index ) { // Scale the index. var scaled = index << 1 ; // Compute start and end. var start = lastCaptureInfo [ CAPTURE ( scaled ) ] ; // If start isn't valid, return undefined. if ( start < 0 ) return ; var end = lastCaptureInfo [ CAPTURE ( scaled + 1 ) ] ; return % _SubString ( string , <mask> , end ) ; }