Add global variables to DAX

'This idea is extremely under-appreciated. To help others searching for the same feature, let me add some additional keywords that hopefully clarifies the point of this (so the idea can get the votes it deserves): - Dynamic table - Shared table variable - Table-valued measure - Reuse table variable - Global filter context - Shared filter context - Reuse filter context Let me try to explain why this feature would be immensely powerful and useful to all sorts of Tabular modeling: 1. Encapsulation of filtering logic into reusable pieces: Within the context of a single measure or calculated column, DAX variables are incredibly useful for logic that needs to be reused several places. It makes the code more readable, and my experience is that Formula Engine performance also improves through the proper use of variables. For logic that depends on a single value, today we can easily use intermediate measures to achieve encapsulation, and reuse logic across several measures. However, we don't have a way of doing the same thing for logic that depends on a filter context, which means that you will often need to do the exact same table calculation or filtering in multiple measures and calculated columns, making the solution more cumbersome and difficult to maintain. If the logic changes slightly, the change needs to be manually applied to several objects. 2. Simulation of SCOPE statements in DAX One of the most powerful features of Analysis Services Multidimensional is the MDX SCOPE statement, which is not available in Tabular. Using SCOPE allows us to change the context over which MDX expressions are evaluated. One obvious usage is the DateTool time intelligence pattern (http://sqlblog.com/blogs/marco_russo/archive/2007/09/02/datetool-dimension-an-alternative-time-intelligence-implementation.aspx). Today, in Tabular, we can achieve a similar thing using a Tool dimension, but the downside is that we need to add calendar filtering logic within every single measure. If we h