Implemented contains operator

docs/content/3.manual/manual.yml

@@ -522,7 +522,33 @@ sections:
           - program: '.[] == 1'
             input: '[1, 1.0, "1", "banana"]'
             output: ['[true, true, false, false]']
-          
+      - title: `contains`
+        body: |
+
+          The expression 'a contains b' will produce true if b is completely
+          contained within a. A string B is contained in a string A if B is a
+          substring of A. An array B is contained in an array A is all elements
+          in B are contained in any element in A. An object B is contained in
+          object A if all of the values in B are contained in the value in A with
+          the same key. All other types are assumed to be contained in each other
+          if they are equal.
+
+        examples:
+          - program: '. == contains "bar"'
+            input: '"foobar"'
+            output: ['true']
+          - program: '. contains ["baz", "bar"]'
+            input: '["foobar", "foobaz", "blarp"]'
+            output: ['true']
+          - program: '. contains ["bazzzzz", "bar"]'
+            input: '["foobar", "foobaz", "blarp"]'
+            output: ['false']
+          - program: '. contains {foo: 12, bar: [{barp: 12}]}'
+            input: '{foo: 12, bar:[1,2,{barp:12, blip:13}]}'
+            output: ['true']
+          - program: '. contains {foo: 12, bar: [{barp: 15}]}'
+            input: '{foo: 12, bar:[1,2,{barp:12, blip:13}]}'
+            output: ['false']
       - title: if-then-else
         body: |