js.compile.ignore=true
=====
>>> main.whiley
property update(int[] items, int x, int y) -> (int[] r):
if x >= 0 && x < |items|:
return items[x:=y]
else:
return items
public export method test():
int[] xs = [1,2,3]
assert update(xs,0,2) == [2,2,3]
assert update(xs,1,4) == [1,4,3]
assert update(xs,2,123) == [1,2,123]
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