Balanced brackets: Difference between revisions

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@@ Line 5,503: / Line 5,503: @@
 ][]]][[[        NOT OK
 [[[][]]]        OK
+</pre>
+=={{header|Picat}}==
+Here are two approaches: one "traditional" and one using DCGs.
+<lang picat> go ?=>
+  go1,
+  go_dcg,
+  nl.
+go => true.
+% "Traditional" approach
+go1 ?=>
+  tests(Tests),
+  member(Test,Tests),
+  printf("%s: ", Test),
+  (  balanced_brackets(Test) ->
+       println("OK")
+     ;
+       println("NOT OK")
+  ),
+  fail,
+  nl.
+go1 => true.
+% DCG
+go_dcg ?=>
+  tests(Tests),
+  foreach(Test in Tests)
+    printf("%s: ", Test),
+    if balanced(Test,[]) then
+      println("OK")
+    else
+      println("NOT OK")
+    end
+  end,
+  nl.
+go_dcg => true.
+% Check if a string of [] is balanced
+balanced_brackets(B) =>
+   C = 0,
+   foreach(I in 1..B.length, C >= 0)
+      C:= C + cond(B[I] = '[', 1, -1)
+   end,
+   C == 0.
+% Using DCG
+balanced --> "".
+balanced --> "[", balanced, "]", balanced.
+tests(["","[]", "[][]", "[[][]]", "][",
+       "][][", "[]][[]", "[][][][][][][][][][]",
+       "[[[[[[[]]]]]]]", "[[[[[[[]]]]]]",
+       "[][[]][]","[[][]][]", "[][][[]][]"]).
+</lang>
+Output:
+<pre>
+: OK
+[]: OK
+[][]: OK
+[[][]]: OK
+][: NOT OK
+][][: NOT OK
+[]][[]: NOT OK
+[][][][][][][][][][]: OK
+[[[[[[[]]]]]]]: OK
+[[[[[[[]]]]]]: NOT OK
+[][[]][]: OK
+[[][]][]: OK
+[][][[]][]: OK
+: OK
+[]: OK
+[][]: OK
+[[][]]: OK
+][: NOT OK
+][][: NOT OK
+[]][[]: NOT OK
+[][][][][][][][][][]: OK
+[[[[[[[]]]]]]]: OK
+[[[[[[[]]]]]]: NOT OK
+[][[]][]: OK
+[[][]][]: OK
+[][][[]][]: OK
 </pre>