Hi all,<div><br></div><div>As discussed in an earlier (accepted) proposal we&#39;re adding Data.[Int]Map.{Strict,Lazy} APIs to make it easier for users to get the desired strictness.</div><div><br></div><div>There are two subtly different ways these APIs can be strict:</div>

<div><br></div><div>1. All the functions are strict in the value argument, or</div><div>2. The structure is strict in the value field.</div><div><br></div><div>The difference shows up in functions like insertWith. For example, given</div>

<div><br></div><div>    insertWith (\ old _new -&gt; old + 1) k v someMap</div><div><br></div><div>should &#39;v&#39; be evaluated is the key &#39;k&#39; is already in the map. (Note that the value isn&#39;t used in the update function.)</div>

<div><br></div><div>If we go with option 2 it is more difficult for the user to reason about if a given value passed to the API is evaluated or not (as in the above example). We currently use option 1 for keys i.e.</div>
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<br></div><div>    insert k v someMap</div><div><br></div><div>is strict in the key even if the map is empty (which wouldn&#39;t require us to look at the key).</div><div><br></div><div>Thoughts? I&#39;d love to see some design pros/cons of both approaches.</div>

<div><br></div><div>-- Johan</div><div><br></div>