Expr Language - User Functions

A user function allows you to define a locally-used function within a formula. User functions can be defined in a similar manner as local variables:

WITH square(x) = x * x : 
  square(impactField) / square(storyPoints)

In this example, the user function is given a name ("square") and then used to perform the same calculation on multiple fields. To learn more, see the language reference.
Embeded JQL Queries
Variables are user-defined names, which represent Jira issue fields., using a construct similar to Aggregate Functions. The result will be a boolean value:

1 (true) if the current row matches the query
0 (false) otherwise

For example:

// Collect total story points from all sub-issues assigned to members of Team2 group
SUM { 
    IF JQL { assignee in membersOf("Team2") } : 
      storyPoints
}