// List helpers

/*!
  Flattens a list one level:

  flatten([[0,1],[2,3]]) => [0,1,2,3]
*/
function flatten(list) = [ for (i = list, v = i) v ];


/*!
  Creates a list from a range:

  range([0:2:6]) => [0,2,4,6]
*/
function range(r) = [ for(x=r) x ];

/*!
  Reverses a list:

  reverse([1,2,3]) => [3,2,1]
*/
function reverse(list) = [for (i = [len(list)-1:-1:0]) list[i]];

/*!
  Extracts a subarray from index begin (inclusive) to end (exclusive)
  FIXME: Change name to use list instead of array?

  subarray([1,2,3,4], 1, 2) => [2,3]
*/
function subarray(list,begin=0,end=-1) = [
    let(end = end < 0 ? len(list) : end)
      for (i = [begin : 1 : end-1])
        list[i]
];

/*!
  Returns a copy of a list with the element at index i set to x

  set([1,2,3,4], 2, 5) => [1,2,5,4]
*/
function set(list, i, x) = [for (i_=[0:len(list)-1]) i == i_ ? x : list[i_]];

/*!
  Remove element from the list by index.
  remove([4,3,2,1],1) => [4,2,1]
*/
function remove(list, i) = [for (i_=[0:1:len(list)-2]) list[i_ < i ? i_ : i_ + 1]];