A-M baby

Task/Find-common-directory-path/Maxima/find-common-directory-path.maxima

@@ -0,0 +1,11 @@
+scommon(a, b) := block([n: min(slength(a), slength(b))],
+   substring(a, 1, catch(for i thru n do (
+   if not cequal(charat(a, i), charat(b, i)) then throw(i)), n + 1)))$
+
+commonpath(u, [l]) := block([s: lreduce(scommon, u), c, n],
+   n: sposition(if length(l) = 0 then "/" else l[1], sreverse(s)),
+   if integerp(n) then substring(s, 1, slength(s) - n) else ""
+)$
+
+commonpath(["c:/files/banister.jpg", "c:/files/bank.xls", "c:/files/banana-recipes.txt"]);
+"c:/files"