Data commit

Task/Balanced-brackets/Ceylon/balanced-brackets.ceylon

@@ -0,0 +1,27 @@
+import com.vasileff.ceylon.random.api {
+    platformRandom,
+    Random
+}
+"""Run the example code for Rosetta Code ["Balanced brackets" task] (http://rosettacode.org/wiki/Balanced_brackets)."""
+shared void run() {
+    value rnd = platformRandom();
+    for (len in (0..10)) {
+        value c = generate(rnd, len);
+        print("``c.padTrailing(20)`` - ``if (balanced(c)) then "OK" else "NOT OK" ``");
+    }
+}
+
+String generate(Random rnd, Integer count)
+        => if (count == 0) then ""
+           else let(length = 2*count,
+                    brackets = zipEntries(rnd.integers(length).take(length),
+                                          "[]".repeat(count))
+                            .sort((a,b) => a.key<=>b.key)
+                            .map(Entry.item))
+                String(brackets);
+
+Boolean balanced(String input)
+        => let (value ints = { for (c in input) if (c == '[') then 1 else -1 })
+           ints.filter((i) => i != 0)
+               .scan(0)(plus<Integer>)
+               .every((i) => i >= 0);