Bug 189706 Enhance computed column aggregation function handling in UI.
Due to the issue discussed in 189705, current computed column aggregation builder in data set editor has bugs to extend: 1.When new a computed column, the aggregation argument field cannot be correctly set. 2.The argument field cannot be correct grayed out when user select a aggregation function without arguments 3.The available aggregation function list is incomprehensive 4.Some aggregation function cannot be set to model(say, weightedAve).
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/expression/ExpressionProcessor.java
}
		return currentHelper;
	}
	
	/*
	 * @see org.eclipse.birt.data.engine.executor.transform.IExpressionProcessor#getScope()
	 */
	public Scriptable getScope( )
	{
		return this.dataset.getScriptScope( );
	}
	
	/*
	 * @see org.eclipse.birt.data.engine.executor.transform.IExpressionProcessor#setResultSetPopulator(org.eclipse.birt.data.engine.executor.transform.ResultSetPopulator)
	 */
	public void setResultSetPopulator( ResultSetPopulator rsPopulator )
	{
		this.rsPopulator = rsPopulator;
	}
	
	/*
	 * @see org.eclipse.birt.data.engine.executor.transform.IExpressionProcessor#setDataSetMode(boolean)
	 */
	public void setDataSetMode( boolean isDataSetMode )
	{
		this.isDataSetMode = isDataSetMode;
	}
	
	/*
	 * @see org.eclipse.birt.data.engine.executor.transform.IExpressionProcessor#setQuery(org.eclipse.birt.data.engine.executor.BaseQuery)