The let and get Streaming Expressions allows the tuples in a stream to be assigned to a variable so it can be used more then once during an expression.
This builds on the list and cell expressions (SOLR-10551)
Here is the sample syntax:
In the example above the let expression is saving the contents of two cell expressions (a, b). The get expression is retrieving the tuples and using them later in the expression.
So for example two facet expressions could be stored in the let, and then displayed and correlated later in the expression.