<p>[[Home]] | [[Installing]] | [[Expression Trees]] | [[Pynq Factory]]</p>
<p>Pynq implements expression trees as means for different providers to query whatever it is that they want to query using the same language.</p>
<h2>Implemented Expression Tree Nodes</h2>
<h3>Unary Expressions</h3>
<p>Unary expressions are expressions that operate on a single expression. They are always in the form of: “operator(value)”.</p>
<ul>
<li>Negate – Mathematically negates the given expression. i.e.: -(10)</li>
<li>Not – Boolean “not” operator for the given expression. i.e.: not (item.boolean_property)</li>
<li>CollectionLength – Returns the collection length for a given collection. i.e.: len(item.collection_property)</li>
</ul>
<h3>Binary Expressions</h3>
<p>Binary expressions are expressions that take two other expressions as parameters. They are always in the form of: “value1 operator value2”.</p>
<p>Arithmetic:</p>
<ul>
<li>Add – Regular addition of two values. i.e.: 2+2</li>
<li>Subtract – Regular subtraction of two values. i.e.: 2-2</li>
<li>Multiply – Regular multiply of two values. i.e.: 2*2</li>
<li>Divide – Regular division of two values. i.e.: 2/2</li>
<li>Power – Power operation of two values. i.e.: 2 ** 2 (meaning 2 to the power of 2)</li>
<li>Modulo – Modulo operation of two values. i.e.: 4 % 2 (meaning the remainder of division of 4 by 2)</li>
</ul>
<p>Boolean:</p>
<ul>
<li>And – Boolean “and” operation. i.e.: True and False</li>
<li>Or – Boolean “or” operation. i.e.: True or False</li>
</ul>
<p>Comparison:</p>
<ul>
<li>Equal – Equality comparison. i.e.: property == 10</li>
<li>NotEqual – Non-equality comparison. i.e.: property != 10</li>
<li>GreaterThan – Compares if first value is greater than the second value. i.e.: 2 > 3</li>
<li>GreaterThanOrEqual – Compares if first value is greater than or equal to the second value. i.e.: 2 >= 2</li>
<li>LessThan – Compares if first value is less than the second value. i.e.: 3 < 2</li>
<li>LessThanOrEqual – Compares if first value is less than or equal to second value. i.e.: 2 <= 2</li>
</ul>
2009-11-24T02:53:16-08:00
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Expression Trees
2009-05-02T21:16:54-07:00
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