ecmascript:

var key, keyValue;

function initialize()
{
	key      = keyHolderNode.key;
	keyValue = keyValueHolderNode.description;
	tracePrint('key =' + key);
	tracePrint('keyValue =' + keyValue);
	keyValueToKeyValueArray ();
	tracePrint('keyValueArray =' + keyValueArray);

	forward = true;
	tracePrint('Initializing a new BooleanSequencer.  key.length=' + key.length + '; keyValueArray.length=' + keyValueArray.length);
	validityCheck();
}

function keyValueToKeyValueArray ()
{
	tracePrint('keyValueToKeyValueArray starting');
	index = 0;
	complete = false;
	nextString = keyValue.toLowerCase();
	tracePrint('initial nextString=' + nextString);
	tokenCount=0;
	while ((complete != true) && (nextString.length > 0))
	{
		tracePrint('nextString=' + nextString);
		while ((nextString.substring(0,1) == ' ') || (nextString.substring(0,1) == ','))
		       nextString = nextString.slice(1);
		tracePrint('deblanked nextString=' + nextString);
		if (nextString.length == 0)
		{
			tracePrint ('nextString.length == 0');
			complete = true;
		}
		if (nextString.length < 4)
		{
			forcePrint ('*** illegal keyValue input=' + nextString);
			valid = false;
			complete = true;
		}
		else if (nextString.substring(0,4) =='true')
		{
			keyValueArray[keyValueArray.length] = 1; // append
			newString = nextString.slice(4);
			nextString = newString;
			tokenCount++;
			tracePrint('found true, nextString=' + nextString + ', tokenCount=' + tokenCount);
		}
		else if (nextString.length < 5)
		{
			forcePrint ('*** illegal keyValue input=' + nextString);
			valid = false;
			complete = true;
		}
		else if (nextString.substring(0,5) =='false')
		{
			keyValueArray[keyValueArray.length] = 0; // append
			newString = nextString.slice(5);
			nextString = newString;
			tokenCount++;
			tracePrint('found false, nextString=' + nextString + ', tokenCount=' + tokenCount);
		}
		tracePrint('  intermediate keyValueArray=' + keyValueArray);
	}
	tracePrint('keyValueToKeyValueArray complete');
}

function set_fraction(value, timeStamp)
{
	if (recheckValidity) validityCheck();

	if (!valid) return; //BooleanSequencer ignored

	tracePrint('fraction =' + value);
	//Bounds checking
	if (value < 0)
	{
		forcePrint('*** warning: fraction is less than 0.  fraction reset to 0 ***');
		value = 0;
	}
	else if (value > 1)
	{
		forcePrint('*** warning: fraction is greater than 1.  fraction reset to 1 ***');
		value = 1;
	}

	//Check animation direction
	if (value < previousFraction && forward == true)
	{
		forward = false;
		nextIndex = nextIndex - 1;
		tracePrint('Animate backward');
	}
	else if (value > previousFraction && forward == false)
	{
		forward = true;
		//nextIndex = 0;
		tracePrint('Animate forward');
	}

	previousFraction = value;

	if (forward == true)
	{
		for (i = nextIndex; i < key.length; i++)
		{
			if (value < key[i])
				return;

			nextIndex = i + 1;
			tracePrint('nextIndex =' + nextIndex);
			if (nextIndex < key.length)
			{
				if (value <= key[nextIndex])
				{
					//Fire event
					if (keyValueArray[nextIndex-1] == 0)
						value_changed = false;
					else
						value_changed = true;
					tracePrint('value_changed eventOut is:' + value_changed);
				}
			}
			else if (nextIndex == key.length)
			{
				//Fire event
				if (keyValueArray[nextIndex-1] == 0)
					value_changed = false;
				else
					value_changed = true;
				tracePrint('value_changed eventOut is:' + value_changed);
			}
			else //nextIndex > key.length
			{
				//nextIndex = 0;
				break;
			}
		}
	}
	else //backward
	{
		for (i = nextIndex; i > 0; i--)
		{
			if (value >= key[i])
				return;

			nextIndex = i - 1;
			tracePrint('nextIndex =' + nextIndex);
			if (nextIndex >= 0)
			{
				if (value >= key[nextIndex])
				{
					//Fire event
					if (keyValueArray[nextIndex] == 0)
						value_changed = false;
					else
						value_changed = true;
					tracePrint('value_changed eventOut is:' + value_changed);
				}
			}
			else //nextIndex < 0
			{
				//nextIndex = key.length;
				break;
			}
		}
	}
}

function set_key(value, timeStamp)
{
	key = value;
	keyHolderNode.key  = key;
	recheckValidity = true;
}

function set_keyValue(value, timeStamp)
{
	keyValue = value;
	keyValueHolderNode.description = keyValue;
	recheckValidity = true;
	keyValueToKeyValueArray ();
	keyValue_changed = keyValue;
}

function validityCheck()
{
	//Check if key & keyValueArray array length matches
	if (key.length != keyValueArray.length)
	{
		forcePrint('*** error: key and keyValue arrays must be of the same length.  BooleanSequencer ignored ***');
		valid = false;
		return;
	}

	//Check if key array has values in the range of [0..1] in an increasing order
	if (key[0] < 0 || key[0] > 1)
	{
		forcePrint('*** error: key[0] value is NOT in the range of [0..1].  BooleanSequencer ignored ***');
		valid = false;
		return;
	}
	for (i = 1; i < key.length; i++)
	{
		if (key[i] < 0 || key[i] > 1)
		{
			forcePrint('*** error: key[' + i + '] value is NOT in the range of [0..1].  BooleanSequencer ignored ***');
			valid = false;
			return;
		}

		if (key[i] <= key [i-1])
		{
			forcePrint('*** error: values for key[] array must be listed in an increasing order.  BooleanSequencer ignored ***');
			valid = false;
			return;
		}
	}
	recheckValidity = false;
	key_changed = key;
	return;
}
function previous (SFBoolValue, timestamp)
{
	nextIndex = nextIndex - 1;
	if (nextIndex == 0) nextIndex = key.length - 1;
}
function next (SFBoolValue, timestamp)
{
	nextIndex = nextIndex + 1;
	if (nextIndex == key.length) nextIndex = 0;
}

function tracePrint(outputString)
{
	if (traceEnabled) Browser.print ('[ BooleanSequencer ]' + outputString);
}

function forcePrint(outputString)
{
	Browser.print ('[ BooleanSequencer ]' + outputString);
}