assistance-engine/docs/developer.avapframework.com/chapter9_16.md

6.2.4. Comprehensions for Lists, Sets and Dictionaries

To construct a list, set, or dictionary, AVAP provides special syntax called "comprehension," each in two flavors:

• The contents of the container are listed explicitly.
• They are computed using a set of loop and filtering instructions, called a "comprehension."

Common syntax elements for comprehensions are:

comprehension ::=  assignment_expression comp_for
comp_for      ::=  "for" target_list "in" or_test [comp_iter]
comp_iter     ::=  comp_for | comp_if
comp_if       ::=  "if" or_test [comp_iter]

A comprehension consists of a single expression followed by at least one for clause and zero or more for or if clauses. In this case, the elements of the new container are those produced by considering each for or if clause as a block, nested from left to right, and evaluating the expression to produce an element each time the innermost block is reached.