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copied!<p><em>Edit: three-years later; the times, they are a-changin'…</em></p> <p><a href="https://stackoverflow.com/a/1269798/154694">Julik's answer</a> is the simplest and best way to tackle the problem these days:</p> <pre><code>class Foo attr_accessor :dead alias_method :dead?, :dead # will pick up the reader method end </code></pre> <p>My answer to the original question follows, for posterity…</p> <hr> <p>The short version:</p> <p>You can't use a question mark in the name of an instance variable.</p> <p>The longer version:</p> <p>Take, for example, <code>attr_accessor :foo</code> — it's <del>simply</del> conceptually a bit of syntactic sugar for the following:</p> <pre><code>def foo @foo end def foo=(newfoo) @foo = newfoo end </code></pre> <p>Furthermore, the question-mark suffix is mostly just a convention to indicate that the return value of a method is a boolean.</p> <p>The best approximation I can make of what you're going for here…</p> <pre><code>class MyClass def initialize @awesome = true end def awesome? @awesome end end </code></pre> <p>In this case, there may be a case to be made for using <code>attr_accessor</code> — after all, it may be explicit that you're working directly with a boolean attribute. Generally, I save the question-mark suffix for when I am implementing a method whose boolean return value is based on slightly more complex conditions than just the value of an attribute.</p> <p>Cheers!</p> <hr> <p><em>Edit, two years later, after a recent comment:</em></p> <ol> <li>Ruby enforces certain naming conventions. <del>Symbols in Ruby can't have question marks. Thus invocations of <code>:my_boolean_attribute?</code> both will fail with a <code>NameError</code>.</del> Edit: not correct, just use the quoted syntax for a symbol, e.g., <code>:"my_attribute?"</code></li> <li>Symbols are immutable, attempting to assign to one will throw a <code>SyntaxError</code>.</li> </ol>

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