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POIs it good form to expose derived values as properties?
 

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    <p>I need to <strong>derive an important value given 7 potential inputs</strong>. <a href="http://en.wikipedia.org/wiki/Robert_Cecil_Martin" rel="nofollow noreferrer">Uncle Bob</a> urges me to avoid functions with that many parameters, so I've <a href="http://www.refactoring.com/catalog/extractClass.html" rel="nofollow noreferrer">extracted the class</a>. All parameters now being properties, I'm left with a calculation method with no arguments.</p> <p>“That”, I think, “could be a property, but I'm not sure if that's idiomatic C#.” </p> <p>Should I <strong>expose the final result as a property, or as a method with no arguments</strong>? Would the average C# programmer find properties confusing or offensive? What about the Alt.Net crowd? </p> <pre><code>decimal consumption = calculator.GetConsumption(); // obviously derived decimal consumption = calculator.Consumption; // not so obvious </code></pre> <p>If the latter: should I <strong>declare interim results as [private] properties</strong>, also? Thanks to heavy <a href="http://www.refactoring.com/catalog/extractMethod.html" rel="nofollow noreferrer">method extraction</a>, I have several interim results. Many of these shouldn't be part of the public API. Some of them could be interesting, though, and my expressions would look cleaner if I could access them as properties:</p> <pre><code>decimal interim2 = this.ImportantInterimValue * otherval; </code></pre> <p><strong>Happy Experiment Dept.:</strong></p> <p>While debugging my code in VS2008, I noticed that I kept hovering my mouse over the method calls that compute interim results, expecting a hover-over with their return value. After turning all methods into properties, I found that <strong>exposing interim results as properties greatly assisted debugging.</strong> I'm well pleased with that, but have lingering concerns about readability.</p> <p>The interim value declarations look messier. The expressions, however, are easier to read without the brackets. I no longer feel compelled to start the method name with a verb. To contrast: </p> <pre><code>// Clean method declaration; compulsive verby name; callers need // parenthesis despite lack of any arguments. decimal DetermineImportantInterimValue() { return this.DetermineOtherInterimValue() * this.SomeProperty; } // Messier property declaration; clean name; clean access syntax decimal ImportantInterimValue { get { return this.OtherInterimValue * this.SomeProperty; } } </code></pre> <p>I should perhaps explain that I've been coding in Python for a decade. I've been left with a tendency to spend extra time making my code easier to call than to write. I'm not sure the Python community would regard this property-oriented style as acceptably “Pythonic”, however:</p> <pre><code>def determineImportantInterimValue(self): "The usual way of doing it." return self.determineOtherInterimValue() * self.someAttribute importantInterimValue = property( lambda self =&gt; self.otherInterimValue * self.someAttribute, doc = "I'm not sure if this is Pythonic...") </code></pre>
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