Problem Statement

Create a routine that, given a set of strings representing directory paths and a single character directory separator, will return a string representing that part of the directory tree that is common to all the directories. Test your routine using the forward slash '/' character as the directory separator and the following three strings as input paths: Note: The resultant path should be the valid directory '/home/user1/tmp' and not the longest common string '/home/user1/tmp/cove'. If your language has a routine that performs this function (even if it does not have a changeable separator character), then mention it as part of the task.

Let's start with the solution:

#!/usr/bin/lasso9

local(
	path1 = '/home/user1/tmp/coverage/test' -> split('/'),
	path2 = '/home/user1/tmp/covert/operator' -> split('/'),
	path3 = '/home/user1/tmp/coven/members' -> split('/')
)

define commonpath(...) => {
	local(shared = #rest -> get(1))
	loop(#rest -> size - 1) => {
		#shared = #shared -> intersection(#rest -> get(loop_count + 1))
	}
	return #shared -> join('/')
}

stdoutnl(commonpath(#path1, #path2, #path3))