code for Fibonacci series in Appian

TEST_AddValueToLastInList(list, value):
append(ri!list, reverse(ri!list)[1] + reverse(ri!list)[2]),

reduce(
  rule!TEST_AddValueToLastInList(list:_, value:_),
  {0, 1},
  enumerate(30)
)

{0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181, 6765, 10946, 17711, 28657, 46368, 75025, 121393, 196418, 317811, 514229, 832040, 1346269}

TEST_AddValueToLastInList(list, value):
append(ri!list, reverse(ri!list)[1] + reverse(ri!list)[2]),

reduce(
  rule!TEST_AddValueToLastInList(list:_, value:_),
  {0, 1},
  enumerate(30)
)

{0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181, 6765, 10946, 17711, 28657, 46368, 75025, 121393, 196418, 317811, 514229, 832040, 1346269}

can it be done using localVariables ?

As far as I can tell this function needs to be called recursively (or at least via the reduce() function), hence the expression rule 'TEST_AddValueToLastInList'.

What would local variables add?

But you could store the initial list value "{0,1}" and the numbers "enumerate(30" into locals.