Marco Russo and Alberto Ferrari are linguists:
When calculation groups were introduced in 2019, we did not have a way to describe them in a textual form. A calculation group was represented as a table with one visible column and one or more rows, one for each calculated item. Each calculation item could have one or two DAX expressions associated with it – one for the calculation item itself and an optional one for the format string. Describing a calculation group in an article often required the writer to include screenshots of the Tabular Editor user interface, plus comments in the sample code to explain where each DAX expression should be placed in the user interface.
From the start we proposed a syntax to describe an entire calculation group in a textual form. However, there was no tool able to convert that syntax into the actual object in the Tabular model. For this reason, in the initial version of the articles about calculation groups we used a “pseudo-syntax” and we included comments that made the code more verbose and not necessarily easier to read. However, Tabular Editor 3 introduced the full DAX script syntax for calculation groups that we had hoped would be available in 2019. We decided to adopt that syntax in our content. We use this article as a guide to introduce and explain the DAX Script syntax for calculation groups.
Go check it out.