anchor.diff:  ==== Collection comprehension vs. `map` and `filter`
   
   Collection comprehension is actually quite similar to using `map` and `filter`
  -HOF on a collection. Indeed, a comprehension such as:
  +higher-order function on a collection. Indeed, a comprehension such as:
   [source,golo]
   ----
   list[f(x) foreach x in aList when pred(x)]
  
positive.code: let l2 = l2: filter(|x| -> (x % 2) == 0): map(|x| -> x * 2)
  ----
  
  The general syntax is an collection literal containing an expression followed
  by one or more loop-like expression. If more than one loop is given, it is
  equivalent to nested loops. Thus
  [source,golo]
  
negative.code: # dices == set[2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]
  ----
  
  However, the result collection can only be of the type of one of the predefined 
  collection literal types.
  
  xref:_destructuring[Destructuring] can also be used in collection
  comprehension, as in
  