+import "StandardLibrary"
+
+Concat ?x ?y ?z :-
+ @bbf 1
+ ?z = ?x + ?y
+
+ @bfb 0.5
+ startsWith ?z ?x
+ ?y = drop (length ?x) ?z
+
+ @fbb 0.5
+ endsWith ?z ?y
+ ?x = take (length ?z - length ?y) ?z
+
+main = select ?y where
+ Concat "Hello " ?y "Hello world!"
+--
+[world!]
\ No newline at end of file