Unravel all the Possibilities

Write a function that takes in a string and returns all possible combinations. Return the final result in alphabetical order.

Examples

unravel("a[b|c]") ➞ ["ab", "ac"]

unravel("a[b|c]de[f|g]") ➞ ["abdef", "acdef", "abdeg", "acdeg"]

unravel("a[b]c[d]") ➞ ["abcd"]

unravel("a[b|c|d|e]f") ➞ ["abf", "acf", "adf", "aef"]

unravel("apple [pear|grape]") ➞ ["apple grape", "apple pear"]

Notes

Think of each element in every block (e.g. [a|b|c]) as a fork in the road.