nim-wiki/Feature-Matrix.md

<table>

<tr>
  <th>Language feature</th>

  <th>Scheduled for</th>

  <th>Notes</th>

</tr>



<tr>
  <td>Automatic dereference in more contexts</td>

  <td>0.9.6</td>

  <td>important to be able to write more generic containers easily</td>

</tr>



<tr>
  <td>support overloading of the assignment operator</td>

  <td>0.9.6</td>

  <td>like <tt class="docutils literal"><span class="pre">fields</span></tt> and destructors an assignment operator needs to be lifted</td>

</tr>



<tr>
  <td>destructors need to interact with finalizers</td>

  <td>0.9.6</td>

  <td>destructors and finalizers are implemented, but do not interact. <tt class="docutils literal"><span class="pre">new</span></tt> which takes a finalizer needs to be deprecated. People should use a destructor instead</td>

</tr>



<tr>
  <td>the new concurrency model</td>

  <td>0.9.6</td>

  <td>this requires frontend and backend changes, but no changes to the runtime/GC</td>

</tr>



<tr>
  <td>weaken the requirements for forward declarations</td>

  <td>after 1.0</td>

  <td>two different design ideas exist: one conservative and so will work, the other highly experimental</td>

</tr>



<tr>
  <td>comment handling is weird</td>

  <td>0.9.6</td>

  <td>comments should be optional and not part of the grammar, unless it is a documentation comment</td>

</tr>



<tr>
  <td>push pragma needs to be reworked</td>

  <td>after 1.0</td>

  <td>it should be distinguished between 'push' for 'type', 'proc' etc.</td>

</tr>



<tr>
  <td>pragmas are not supported for 'bindSym'</td>

  <td>0.9.6</td>

  <td>this makes clean macros impossible to write when it comes to pragmas</td>

</tr>



<tr>
  <td>type checking for tuples</td>

  <td>0.9.8</td>

  <td>needs to be refined. Recursive tuples should be forbidden.</td>

</tr>



<tr>
  <td>extended macros API</td>

  <td>0.9.8</td>

  <td>missing: an API for working with types; the builtin getImpl</td>

</tr>



<tr>
  <td>write tracking</td>

  <td>0.9.8</td>

  <td>algorithm exists. Can be extended to compute lent pointers.</td>

</tr>

<tr>
  <td>asFunc pragma</td>
  <td>0.9.8</td>
  <td>provides a nice bridge from 'var T' to 'returns T'; can be entirely implemented as a macro with the upcoming types API
</tr>

<tr>
  <td>prevent object branch transitions from low(selector)</td>

  <td>after 1.0</td>

  <td>object branch transitions from low(selector) are allowed, because they are simply too useful, but can break memory safety. Now that the language has a proper notion of construction, we can make them safe.</td>

</tr>



<tr>
  <td><tt class="docutils literal"><span class="pre">~</span></tt> operator for effects</td>

  <td>after 1.0</td>

  <td>it is not entirely clear what <tt class="docutils literal"><span class="pre">~F</span></tt> should mean.</td>

</tr>



<tr>
  <td>some effects like <tt class="docutils literal"><span class="pre">GCMem</span></tt> don't need to be white-listed</td>

  <td>after 1.0</td>

  <td>unclear whether this only affects built-in properties like <tt class="docutils literal"><span class="pre">GCMem</span></tt>, <tt class="docutils literal"><span class="pre">Recursive</span></tt>.</td>

</tr>



<tr>
  <td>returning 'var T' is unsafe and needs static analysis to make safe</td>

  <td>after 1.0</td>

  <td>the compiler already checks for trivial examples</td>

</tr>



<tr>
  <td>alias analysis needs to specified and controllable with pragmas</td>

  <td>after 1.0</td>

  <td>alias analysis affects memory safety rules</td>

</tr>



<tr>
  <td>term rewriting macros need more love</td>

  <td>after 1.0</td>

  <td>we need much more tests and use them in production</td>

</tr>


<tr>
  <th>Compiler feature</th>

  <th>Scheduled for</th>

  <th>Notes</th>

</tr>



<tr>
  <td>high level optimizer</td>

  <td>after 1.0</td>

  <td>use the effect system for optimizations; interacts with TR macros; 
      performs:<ul>
      <li>GCSE</li>

      <li>loop invariant hoisting</li>

      <li>escape analysis for string/seq</li>

      <li>inlining of small lambdas</li>

    </ul>

  </td>

</tr>



<tr><td>pure RC'ing GC</td>

  <td>after 1.0</td>

  <td>important for better interoperability with Objective-C</td>

</tr>



<tr>
  <td>GPU backend</td>

  <td>after 1.0</td>
</tr>



<tr>
  <td>symbol files</td>

  <td>after 1.0</td>
  <td>symbol files provide true incremental compilation beyond the caching of generated C code</td>
</tr>



<tr>
  <td>deterministic code generation</td>

  <td>0.9.8</td>
  <td>deterministic code generation makes C code caching much more effective</td>
</tr>

</table>