DOCS-433 operator does a short-circuit eval of expression

Author: kay-kim

source/reference/operator/and.txt

@@ -10,10 +10,14 @@ $and
 
    *Syntax*: ``{ $and: [ { <expression1> }, { <expression2> } , ... , { <expressionN> } ] }`` 
 
-   :operator:`$and` performs a logical ``AND`` operation on an array
-   of *two or more* expressions (e.g. ``<expression1>``,
+   :operator:`$and` performs a logical ``AND`` operation on an array of
+   *two or more* expressions (e.g. ``<expression1>``,
    ``<expression2>``, etc.) and selects the documents that satisfy
-   *all* the expressions in the array.
+   *all* the expressions in the array. With the :operator:`$and`
+   operator, MongoDB performs a short-circuit evaluation of the
+   expressions. If the first expression ``<expression1>`` evaluates to
+   ``false``, MongoDB will skip the evaluation of the remaining
+   expressions.
 
    Consider the following example: 
 
@@ -27,7 +31,7 @@ $and
    - ``price`` field value equals ``1.99`` **and** 
    - ``qty`` field value is less than ``20`` **and**
    - ``sale`` field value is equal to ``true``.
-
+   
    MongoDB provides an implicit ``AND`` operation when specifying a
    comma separated list of expressions. For example, you may write the
    above query as: