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POParameterized types and return values in D why does this not work?
 

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  1. POParameterized types and return values in D why does this not work?
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    <p>OK, it seems my prior problem is now resolved (I've left it below for reference). However, yet another one crops up - again, seemingly something I'm missing. Further up in this code, I declared the following:</p> <pre><code>private: T _data; BinaryTree!(T) _left; BinaryTree!(T) _right; </code></pre> <p>Then after this, I declared these:</p> <pre><code>public: @property T data() {return _data;} @property BinaryTree!(T) left() {return _left;} @property BinaryTree!(T) right() {return _right;} </code></pre> <p>Then, I implemented the following function:</p> <pre><code>void add (T data) { BinaryTree!(T) nearest = findNearest(this, data); if (nearest.data &gt; data) { nearest.left = new BinaryTree!(T) (data); } else { nearest.right = new BinaryTree!(T) (data); } } </code></pre> <p>The compiler is protesting that nearest.left and nearest.right aren't properties, although as nearest is a BinaryTree!(T), this seems rather odd. What am I missing?</p> <hr> <p>OLD PROBLEM:</p> <p>I've recently gotten into D, and was trying to build a binary tree implementation as a way of testing what I've learned by reading about it. Now, I started by declaring it as follows:</p> <pre><code>class BinaryTree(T) </code></pre> <p>I figured this would allow me to parametrize some of the stuff the class holds. More specifically:</p> <pre><code>T _data; BinaryTree!(T) _left; BinaryTree!(T) _right; </code></pre> <p>Now, I then tried writing this:</p> <pre><code>BinaryTree!(T) findNearest (BinaryTree(T) x, T key) { if (x.hasNoChildren || x.data == key) { return x; //found it } else { auto compare = x.data; if (compare &gt; key) { return find (x.left, key); } else { return find (x.right, key); } } } </code></pre> <p>After this, the compiler <em>loudly</em> complained about my function not having a return type. What am I doing wrong here? If it helps to explain, I come from a Java background, and I'm using the dmd compiler inside of Xamarin Studio.</p>
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    1. COWrite setters and everything will work. For example: `@property void left(BinaryTree!(T) left) { _left = left; }`
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    2. COThanks for that. Why is this so, out of interest? The understanding I had of `@property` is that we can have calls like `tree.left` as opposed to `tree.getLeft()`, which is why I'm not sure why you'd use `@property` with _setters_.
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    3. COAnd `tree.left = new_left;` as `tree.setLeft(new_left);`. http://dlang.org/property.html scroll to bottom.
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