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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<title>Runtime Context Data</title>
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<!--Weave of 'Runtime Context Data' generated by Inweb-->
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<ul class="crumbs"><li><a href="../index.html">Home</a></li><li><a href="../inform7n.html">Inform7</a></li><li><a href="index.html">assertions</a></li><li><a href="index.html#5">Chapter 5: Imperative Code</a></li><li><b>Runtime Context Data</b></li></ul></div>
<p class="purpose">To store the circumstances in which a rule phrase should fire.</p>
<ul class="toc"><li><a href="5-rcd.html#SP1">&#167;1. Introduction</a></li><li><a href="5-rcd.html#SP3">&#167;3. Specificity</a></li><li><a href="5-rcd.html#SP4">&#167;4. Activity lists</a></li></ul><hr class="tocbar">
<p class="commentary firstcommentary"><a id="SP1" class="paragraph-anchor"></a><b>&#167;1. Introduction. </b>Runtime context data (RCD) is a set of restrictions on when a body of code can run.
It's intended for rules, but in principle available for any imperative definition.
For example,
</p>
<blockquote>
<p>Before taking a container when the player is in the Box Room: ...</p>
</blockquote>
<p class="commentary">can take effect only if the action is "taking a container" and the condition
about the location applies. Those two restrictions are both stored in its RCD.
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="reserved-syntax">typedef</span><span class="plain-syntax"> </span><span class="reserved-syntax">struct</span><span class="plain-syntax"> </span><span class="reserved-syntax">id_runtime_context_data</span><span class="plain-syntax"> {</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">struct</span><span class="plain-syntax"> </span><span class="identifier-syntax">wording</span><span class="plain-syntax"> </span><span class="identifier-syntax">activity_context</span><span class="plain-syntax">; </span><span class="comment-syntax"> text used to parse...</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">struct</span><span class="plain-syntax"> </span><span class="reserved-syntax">activity_list</span><span class="plain-syntax"> *</span><span class="identifier-syntax">avl</span><span class="plain-syntax">; </span><span class="comment-syntax"> happens only while these activities go on</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">struct</span><span class="plain-syntax"> </span><span class="identifier-syntax">action_pattern</span><span class="plain-syntax"> *</span><span class="identifier-syntax">ap</span><span class="plain-syntax">; </span><span class="comment-syntax"> happens only if the action or parameter matches this</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">void</span><span class="plain-syntax"> *</span><span class="identifier-syntax">plugin_rcd</span><span class="plain-syntax">[</span><span class="identifier-syntax">MAX_PLUGINS</span><span class="plain-syntax">]; </span><span class="comment-syntax"> storage for plugins to attach, if they want to</span>
<span class="plain-syntax">} </span><span class="reserved-syntax">id_runtime_context_data</span><span class="plain-syntax">;</span>
<span class="reserved-syntax">id_runtime_context_data</span><span class="plain-syntax"> </span><span class="function-syntax">RuntimeContextData::new</span><button class="popup" onclick="togglePopup('usagePopup1')"><span class="comment-syntax">?</span><span class="popuptext" id="usagePopup1">Usage of <span class="code-font"><span class="function-syntax">RuntimeContextData::new</span></span>:<br/>Imperative Definitions - <a href="5-id.html#SP6">&#167;6</a><br/>Imperative Definition Families - <a href="5-idf.html#SP7">&#167;7</a></span></button><span class="plain-syntax">(</span><span class="reserved-syntax">void</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">id_runtime_context_data</span><span class="plain-syntax"> </span><span class="identifier-syntax">phrcd</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">phrcd</span><span class="plain-syntax">.</span><span class="identifier-syntax">activity_context</span><span class="plain-syntax"> = </span><span class="identifier-syntax">EMPTY_WORDING</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">phrcd</span><span class="plain-syntax">.</span><span class="identifier-syntax">avl</span><span class="plain-syntax"> = </span><span class="identifier-syntax">NULL</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">phrcd</span><span class="plain-syntax">.</span><span class="identifier-syntax">ap</span><span class="plain-syntax"> = </span><span class="identifier-syntax">NULL</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">for</span><span class="plain-syntax"> (</span><span class="reserved-syntax">int</span><span class="plain-syntax"> </span><span class="identifier-syntax">i</span><span class="plain-syntax">=0; </span><span class="identifier-syntax">i</span><span class="plain-syntax">&lt;</span><span class="identifier-syntax">MAX_PLUGINS</span><span class="plain-syntax">; </span><span class="identifier-syntax">i</span><span class="plain-syntax">++) </span><span class="identifier-syntax">phrcd</span><span class="plain-syntax">.</span><span class="element-syntax">plugin_rcd</span><span class="plain-syntax">[</span><span class="identifier-syntax">i</span><span class="plain-syntax">] = </span><span class="identifier-syntax">NULL</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">PluginCalls::new_rcd_notify</span><span class="plain-syntax">(&amp;</span><span class="identifier-syntax">phrcd</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="identifier-syntax">phrcd</span><span class="plain-syntax">;</span>
<span class="plain-syntax">}</span>
<span class="reserved-syntax">id_runtime_context_data</span><span class="plain-syntax"> *</span><span class="function-syntax">RuntimeContextData::of</span><button class="popup" onclick="togglePopup('usagePopup2')"><span class="comment-syntax">?</span><span class="popuptext" id="usagePopup2">Usage of <span class="code-font"><span class="function-syntax">RuntimeContextData::of</span></span>:<br/>Rules - <a href="6-rls.html#SP18">&#167;18</a></span></button><span class="plain-syntax">(</span><span class="reserved-syntax">imperative_defn</span><span class="plain-syntax"> *</span><span class="identifier-syntax">id</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">id</span><span class="plain-syntax"> == </span><span class="identifier-syntax">NULL</span><span class="plain-syntax">) </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="identifier-syntax">NULL</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">return</span><span class="plain-syntax"> &amp;(</span><span class="identifier-syntax">id</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">body_of_defn</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">runtime_context_data</span><span class="plain-syntax">);</span>
<span class="plain-syntax">}</span>
</pre>
<ul class="endnotetexts"><li>The structure id_runtime_context_data is accessed in 5/rf and here.</li></ul>
<p class="commentary firstcommentary"><a id="SP2" class="paragraph-anchor"></a><b>&#167;2. </b>For the more interesting clauses, see <a href="../if-module/3-scn.html" class="internal">Scenes (in if)</a> and <a href="../if-module/4-rpoa.html" class="internal">Rules Predicated on Actions (in if)</a>,
where the scenes and actions plugins make use of the following extensibility:
</p>
<pre class="definitions code-font"><span class="definition-keyword">define</span> <span class="identifier-syntax">RCD_PLUGIN_DATA</span><span class="plain-syntax">(</span><span class="identifier-syntax">id</span><span class="plain-syntax">, </span><span class="identifier-syntax">rcd</span><span class="plain-syntax">)</span>
<span class="plain-syntax"> ((</span><span class="identifier-syntax">id</span><span class="plain-syntax">##</span><span class="identifier-syntax">_rcd_data</span><span class="plain-syntax"> *) </span><span class="identifier-syntax">rcd</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">plugin_rcd</span><span class="plain-syntax">[</span><span class="identifier-syntax">id</span><span class="plain-syntax">##</span><span class="identifier-syntax">_plugin</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">allocation_id</span><span class="plain-syntax">])</span>
<span class="definition-keyword">define</span> <span class="identifier-syntax">CREATE_PLUGIN_RCD_DATA</span><span class="plain-syntax">(</span><span class="identifier-syntax">id</span><span class="plain-syntax">, </span><span class="identifier-syntax">rcd</span><span class="plain-syntax">, </span><span class="identifier-syntax">creator</span><span class="plain-syntax">)</span>
<span class="plain-syntax"> (</span><span class="identifier-syntax">rcd</span><span class="plain-syntax">)-&gt;</span><span class="identifier-syntax">plugin_rcd</span><span class="plain-syntax">[</span><span class="identifier-syntax">id</span><span class="plain-syntax">##</span><span class="identifier-syntax">_plugin</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">allocation_id</span><span class="plain-syntax">] = (</span><span class="reserved-syntax">void</span><span class="plain-syntax"> *) (</span><span class="identifier-syntax">creator</span><span class="plain-syntax">(</span><span class="identifier-syntax">rcd</span><span class="plain-syntax">));</span>
</pre>
<p class="commentary firstcommentary"><a id="SP3" class="paragraph-anchor"></a><b>&#167;3. Specificity. </b>The following is one of Inform's standardised comparison routines, which
takes a pair of objects A, B and returns 1 if A makes a more specific
description than B, 0 if they seem equally specific, or \(-1\) if B makes a
more specific description than A. This is transitive, and intended to be
used in sorting algorithms.
</p>
<p class="commentary">In this case, laws I to V are applied in turn until one is decisive. If
all of them fail to decide, we return 0.
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="reserved-syntax">int</span><span class="plain-syntax"> </span><span class="function-syntax">RuntimeContextData::compare_specificity</span><button class="popup" onclick="togglePopup('usagePopup3')"><span class="comment-syntax">?</span><span class="popuptext" id="usagePopup3">Usage of <span class="code-font"><span class="function-syntax">RuntimeContextData::compare_specificity</span></span>:<br/>Rules - <a href="6-rls.html#SP14">&#167;14</a></span></button><span class="plain-syntax">(</span><span class="reserved-syntax">id_runtime_context_data</span><span class="plain-syntax"> *</span><span class="identifier-syntax">rcd1</span><span class="plain-syntax">,</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">id_runtime_context_data</span><span class="plain-syntax"> *</span><span class="identifier-syntax">rcd2</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">action_pattern</span><span class="plain-syntax"> *</span><span class="identifier-syntax">ap1</span><span class="plain-syntax"> = </span><span class="identifier-syntax">NULL</span><span class="plain-syntax">, *</span><span class="identifier-syntax">ap2</span><span class="plain-syntax"> = </span><span class="identifier-syntax">NULL</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">parse_node</span><span class="plain-syntax"> *</span><span class="identifier-syntax">sc1</span><span class="plain-syntax"> = </span><span class="identifier-syntax">NULL</span><span class="plain-syntax">, *</span><span class="identifier-syntax">sc2</span><span class="plain-syntax"> = </span><span class="identifier-syntax">NULL</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">wording</span><span class="plain-syntax"> </span><span class="identifier-syntax">AL1W</span><span class="plain-syntax"> = </span><span class="identifier-syntax">EMPTY_WORDING</span><span class="plain-syntax">, </span><span class="identifier-syntax">AL2W</span><span class="plain-syntax"> = </span><span class="identifier-syntax">EMPTY_WORDING</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="named-paragraph-container code-font"><a href="5-rcd.html#SP3_1" class="named-paragraph-link"><span class="named-paragraph">Extract these from the PHRCDs under comparison</span><span class="named-paragraph-number">3.1</span></a></span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="named-paragraph-container code-font"><a href="5-rcd.html#SP3_2" class="named-paragraph-link"><span class="named-paragraph">Apply comparison law I</span><span class="named-paragraph-number">3.2</span></a></span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="named-paragraph-container code-font"><a href="5-rcd.html#SP3_3" class="named-paragraph-link"><span class="named-paragraph">Apply comparison law II</span><span class="named-paragraph-number">3.3</span></a></span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="named-paragraph-container code-font"><a href="5-rcd.html#SP3_4" class="named-paragraph-link"><span class="named-paragraph">Apply comparison law III</span><span class="named-paragraph-number">3.4</span></a></span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="named-paragraph-container code-font"><a href="5-rcd.html#SP3_5" class="named-paragraph-link"><span class="named-paragraph">Apply comparison law IV</span><span class="named-paragraph-number">3.5</span></a></span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="named-paragraph-container code-font"><a href="5-rcd.html#SP3_6" class="named-paragraph-link"><span class="named-paragraph">Apply comparison law V</span><span class="named-paragraph-number">3.6</span></a></span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="constant-syntax">0</span><span class="plain-syntax">;</span>
<span class="plain-syntax">}</span>
</pre>
<p class="commentary firstcommentary"><a id="SP3_1" class="paragraph-anchor"></a><b>&#167;3.1. </b><span class="named-paragraph-container code-font"><span class="named-paragraph-defn">Extract these from the PHRCDs under comparison</span><span class="named-paragraph-number">3.1</span></span><span class="comment-syntax"> =</span>
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">rcd1</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">sc1</span><span class="plain-syntax"> = </span><span class="identifier-syntax">Scenes::get_rcd_spec</span><span class="plain-syntax">(</span><span class="identifier-syntax">rcd1</span><span class="plain-syntax">); </span><span class="identifier-syntax">ap1</span><span class="plain-syntax"> = </span><span class="identifier-syntax">ActionRules::get_ap</span><span class="plain-syntax">(</span><span class="identifier-syntax">rcd1</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">AL1W</span><span class="plain-syntax"> = </span><span class="identifier-syntax">rcd1</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">activity_context</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">rcd2</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">sc2</span><span class="plain-syntax"> = </span><span class="identifier-syntax">Scenes::get_rcd_spec</span><span class="plain-syntax">(</span><span class="identifier-syntax">rcd2</span><span class="plain-syntax">); </span><span class="identifier-syntax">ap2</span><span class="plain-syntax"> = </span><span class="identifier-syntax">ActionRules::get_ap</span><span class="plain-syntax">(</span><span class="identifier-syntax">rcd2</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">AL2W</span><span class="plain-syntax"> = </span><span class="identifier-syntax">rcd2</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">activity_context</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
</pre>
<ul class="endnotetexts"><li>This code is used in <a href="5-rcd.html#SP3">&#167;3</a>.</li></ul>
<p class="commentary firstcommentary"><a id="SP3_2" class="paragraph-anchor"></a><b>&#167;3.2. </b>More constraints beats fewer.
</p>
<p class="commentary"><span class="named-paragraph-container code-font"><span class="named-paragraph-defn">Apply comparison law I</span><span class="named-paragraph-number">3.2</span></span><span class="comment-syntax"> =</span>
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="plain-syntax"> </span><span class="identifier-syntax">Specifications::law</span><span class="plain-syntax">(</span><span class="identifier-syntax">I</span><span class="string-syntax">"I - Number of aspects constrained"</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">int</span><span class="plain-syntax"> </span><span class="identifier-syntax">rct1</span><span class="plain-syntax"> = </span><span class="identifier-syntax">APClauses::count_aspects</span><span class="plain-syntax">(</span><span class="identifier-syntax">ap1</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">int</span><span class="plain-syntax"> </span><span class="identifier-syntax">rct2</span><span class="plain-syntax"> = </span><span class="identifier-syntax">APClauses::count_aspects</span><span class="plain-syntax">(</span><span class="identifier-syntax">ap2</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">sc1</span><span class="plain-syntax">) </span><span class="identifier-syntax">rct1</span><span class="plain-syntax">++; </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">sc2</span><span class="plain-syntax">) </span><span class="identifier-syntax">rct2</span><span class="plain-syntax">++;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">Wordings::nonempty</span><span class="plain-syntax">(</span><span class="identifier-syntax">AL1W</span><span class="plain-syntax">)) </span><span class="identifier-syntax">rct1</span><span class="plain-syntax">++; </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">Wordings::nonempty</span><span class="plain-syntax">(</span><span class="identifier-syntax">AL2W</span><span class="plain-syntax">)) </span><span class="identifier-syntax">rct2</span><span class="plain-syntax">++;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">rct1</span><span class="plain-syntax"> &gt; </span><span class="identifier-syntax">rct2</span><span class="plain-syntax">) </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="constant-syntax">1</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">rct1</span><span class="plain-syntax"> &lt; </span><span class="identifier-syntax">rct2</span><span class="plain-syntax">) </span><span class="reserved-syntax">return</span><span class="plain-syntax"> -1;</span>
</pre>
<ul class="endnotetexts"><li>This code is used in <a href="5-rcd.html#SP3">&#167;3</a>.</li></ul>
<p class="commentary firstcommentary"><a id="SP3_3" class="paragraph-anchor"></a><b>&#167;3.3. </b>If both have scene requirements, a narrow requirement beats a broad one.
</p>
<p class="commentary"><span class="named-paragraph-container code-font"><span class="named-paragraph-defn">Apply comparison law II</span><span class="named-paragraph-number">3.3</span></span><span class="comment-syntax"> =</span>
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> ((</span><span class="identifier-syntax">sc1</span><span class="plain-syntax">) &amp;&amp; (</span><span class="identifier-syntax">sc2</span><span class="plain-syntax">)) {</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">int</span><span class="plain-syntax"> </span><span class="identifier-syntax">rv</span><span class="plain-syntax"> = </span><span class="identifier-syntax">Specifications::compare_specificity</span><span class="plain-syntax">(</span><span class="identifier-syntax">sc1</span><span class="plain-syntax">, </span><span class="identifier-syntax">sc2</span><span class="plain-syntax">, </span><span class="identifier-syntax">NULL</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">rv</span><span class="plain-syntax"> != </span><span class="constant-syntax">0</span><span class="plain-syntax">) </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="identifier-syntax">rv</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
</pre>
<ul class="endnotetexts"><li>This code is used in <a href="5-rcd.html#SP3">&#167;3</a>.</li></ul>
<p class="commentary firstcommentary"><a id="SP3_4" class="paragraph-anchor"></a><b>&#167;3.4. </b>More when/while conditions beats fewer.
</p>
<p class="commentary"><span class="named-paragraph-container code-font"><span class="named-paragraph-defn">Apply comparison law III</span><span class="named-paragraph-number">3.4</span></span><span class="comment-syntax"> =</span>
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="plain-syntax"> </span><span class="identifier-syntax">Specifications::law</span><span class="plain-syntax">(</span><span class="identifier-syntax">I</span><span class="string-syntax">"III - When/while requirement"</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> ((</span><span class="identifier-syntax">Wordings::nonempty</span><span class="plain-syntax">(</span><span class="identifier-syntax">AL1W</span><span class="plain-syntax">)) &amp;&amp; (</span><span class="identifier-syntax">Wordings::empty</span><span class="plain-syntax">(</span><span class="identifier-syntax">AL2W</span><span class="plain-syntax">))) </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="constant-syntax">1</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> ((</span><span class="identifier-syntax">Wordings::empty</span><span class="plain-syntax">(</span><span class="identifier-syntax">AL1W</span><span class="plain-syntax">)) &amp;&amp; (</span><span class="identifier-syntax">Wordings::nonempty</span><span class="plain-syntax">(</span><span class="identifier-syntax">AL2W</span><span class="plain-syntax">))) </span><span class="reserved-syntax">return</span><span class="plain-syntax"> -1;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">Wordings::nonempty</span><span class="plain-syntax">(</span><span class="identifier-syntax">AL1W</span><span class="plain-syntax">)) {</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">int</span><span class="plain-syntax"> </span><span class="identifier-syntax">n1</span><span class="plain-syntax"> = </span><a href="5-rcd.html#SP5" class="function-link"><span class="function-syntax">RuntimeContextData::activity_list_count</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">rcd1</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">avl</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">int</span><span class="plain-syntax"> </span><span class="identifier-syntax">n2</span><span class="plain-syntax"> = </span><a href="5-rcd.html#SP5" class="function-link"><span class="function-syntax">RuntimeContextData::activity_list_count</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">rcd2</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">avl</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">n1</span><span class="plain-syntax"> &gt; </span><span class="identifier-syntax">n2</span><span class="plain-syntax">) </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="constant-syntax">1</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">n2</span><span class="plain-syntax"> &gt; </span><span class="identifier-syntax">n1</span><span class="plain-syntax">) </span><span class="reserved-syntax">return</span><span class="plain-syntax"> -1;</span>
<span class="plain-syntax"> }</span>
</pre>
<ul class="endnotetexts"><li>This code is used in <a href="5-rcd.html#SP3">&#167;3</a>.</li></ul>
<p class="commentary firstcommentary"><a id="SP3_5" class="paragraph-anchor"></a><b>&#167;3.5. </b>A more specific action (or parameter) beats a less specific one.
</p>
<p class="commentary"><span class="named-paragraph-container code-font"><span class="named-paragraph-defn">Apply comparison law IV</span><span class="named-paragraph-number">3.5</span></span><span class="comment-syntax"> =</span>
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="plain-syntax"> </span><span class="identifier-syntax">Specifications::law</span><span class="plain-syntax">(</span><span class="identifier-syntax">I</span><span class="string-syntax">"IV - Action requirement"</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">int</span><span class="plain-syntax"> </span><span class="identifier-syntax">rv</span><span class="plain-syntax"> = </span><span class="identifier-syntax">ActionPatterns::compare_specificity</span><span class="plain-syntax">(</span><span class="identifier-syntax">ap1</span><span class="plain-syntax">, </span><span class="identifier-syntax">ap2</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">rv</span><span class="plain-syntax"> != </span><span class="constant-syntax">0</span><span class="plain-syntax">) </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="identifier-syntax">rv</span><span class="plain-syntax">;</span>
</pre>
<ul class="endnotetexts"><li>This code is used in <a href="5-rcd.html#SP3">&#167;3</a>.</li></ul>
<p class="commentary firstcommentary"><a id="SP3_6" class="paragraph-anchor"></a><b>&#167;3.6. </b>A rule with a scene requirement beats one without.
</p>
<p class="commentary"><span class="named-paragraph-container code-font"><span class="named-paragraph-defn">Apply comparison law V</span><span class="named-paragraph-number">3.6</span></span><span class="comment-syntax"> =</span>
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="plain-syntax"> </span><span class="identifier-syntax">Specifications::law</span><span class="plain-syntax">(</span><span class="identifier-syntax">I</span><span class="string-syntax">"V - Scene requirement"</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> ((</span><span class="identifier-syntax">sc1</span><span class="plain-syntax"> != </span><span class="identifier-syntax">NULL</span><span class="plain-syntax">) &amp;&amp; (</span><span class="identifier-syntax">sc2</span><span class="plain-syntax"> == </span><span class="identifier-syntax">NULL</span><span class="plain-syntax">)) </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="constant-syntax">1</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> ((</span><span class="identifier-syntax">sc1</span><span class="plain-syntax"> == </span><span class="identifier-syntax">NULL</span><span class="plain-syntax">) &amp;&amp; (</span><span class="identifier-syntax">sc2</span><span class="plain-syntax"> != </span><span class="identifier-syntax">NULL</span><span class="plain-syntax">)) </span><span class="reserved-syntax">return</span><span class="plain-syntax"> -1;</span>
</pre>
<ul class="endnotetexts"><li>This code is used in <a href="5-rcd.html#SP3">&#167;3</a>.</li></ul>
<p class="commentary firstcommentary"><a id="SP4" class="paragraph-anchor"></a><b>&#167;4. Activity lists. </b>The activity list part of a RCD is a list of activities, one of which must
be currently running for the rule to fire. For example, in:
</p>
<blockquote>
<p>Rule for printing the name of the lemon sherbet while listing contents: ...</p>
</blockquote>
<p class="commentary">the activity list is just "listing contents". These are like action patterns,
but much simpler to parse &mdash; an or-divided list of activities can be given,
with or without operands; "not" can be used to negate the list; and ordinary
conditions are also allowed, as here:
</p>
<blockquote>
<p>Rule for printing the name of the sack while the sack is not carried: ...</p>
</blockquote>
<p class="commentary">where "the sack is not carried" is also a &lt;run-time-context&gt; even though
it mentions no activities.
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="reserved-syntax">typedef</span><span class="plain-syntax"> </span><span class="reserved-syntax">struct</span><span class="plain-syntax"> </span><span class="reserved-syntax">activity_list</span><span class="plain-syntax"> {</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">struct</span><span class="plain-syntax"> </span><span class="reserved-syntax">activity</span><span class="plain-syntax"> *</span><span class="reserved-syntax">activity</span><span class="plain-syntax">; </span><span class="comment-syntax"> what activity</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">struct</span><span class="plain-syntax"> </span><span class="identifier-syntax">parse_node</span><span class="plain-syntax"> *</span><span class="identifier-syntax">acting_on</span><span class="plain-syntax">; </span><span class="comment-syntax"> the parameter</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">struct</span><span class="plain-syntax"> </span><span class="identifier-syntax">parse_node</span><span class="plain-syntax"> *</span><span class="identifier-syntax">only_when</span><span class="plain-syntax">; </span><span class="comment-syntax"> condition for when this applies</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">int</span><span class="plain-syntax"> </span><span class="identifier-syntax">ACL_parity</span><span class="plain-syntax">; </span><span class="comment-syntax"> </span><span class="extract"><span class="extract-syntax">+1</span></span><span class="comment-syntax"> if meant positively, </span><span class="extract"><span class="extract-syntax">-1</span></span><span class="comment-syntax"> if negatively</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">struct</span><span class="plain-syntax"> </span><span class="reserved-syntax">activity_list</span><span class="plain-syntax"> *</span><span class="identifier-syntax">next</span><span class="plain-syntax">; </span><span class="comment-syntax"> next in activity list</span>
<span class="plain-syntax">} </span><span class="reserved-syntax">activity_list</span><span class="plain-syntax">;</span>
</pre>
<ul class="endnotetexts"><li>The structure activity_list is accessed in 2/ptmn, 2/cs, 2/ps, 2/is, 3/dlr, 3/pr, 3/tr, 3/nuor, 3/uor, 3/tr2, 3/dbtr, 3/rpr, 3/nar, 3/nlpr, 3/nrr, 3/npr, 3/nvr, 3/nar2, 4/rpt, 4/tc, 4/ass, 4/npa, 4/rk, 4/ass2, 4/imp, 5/id, 5/adf, 6/rlb, 6/act, 7/tbl, 7/eqt, 8/tcp, 8/abp, 8/cu and here.</li></ul>
<p class="commentary firstcommentary"><a id="SP5" class="paragraph-anchor"></a><b>&#167;5. </b>The "count" of an activity list is a measure of its complexity:
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="reserved-syntax">int</span><span class="plain-syntax"> </span><span class="function-syntax">RuntimeContextData::activity_list_count</span><button class="popup" onclick="togglePopup('usagePopup4')"><span class="comment-syntax">?</span><span class="popuptext" id="usagePopup4">Usage of <span class="code-font"><span class="function-syntax">RuntimeContextData::activity_list_count</span></span>:<br/><a href="5-rcd.html#SP3_4">&#167;3.4</a></span></button><span class="plain-syntax">(</span><span class="reserved-syntax">activity_list</span><span class="plain-syntax"> *</span><span class="identifier-syntax">avl</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">int</span><span class="plain-syntax"> </span><span class="identifier-syntax">n</span><span class="plain-syntax"> = </span><span class="constant-syntax">0</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">while</span><span class="plain-syntax"> (</span><span class="identifier-syntax">avl</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">n</span><span class="plain-syntax"> += </span><span class="constant-syntax">10</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">avl</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">only_when</span><span class="plain-syntax">) </span><span class="identifier-syntax">n</span><span class="plain-syntax"> += </span><span class="identifier-syntax">Conditions::count</span><span class="plain-syntax">(</span><span class="identifier-syntax">avl</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">only_when</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">avl</span><span class="plain-syntax"> = </span><span class="identifier-syntax">avl</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">next</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="identifier-syntax">n</span><span class="plain-syntax">;</span>
<span class="plain-syntax">}</span>
</pre>
<p class="commentary firstcommentary"><a id="SP6" class="paragraph-anchor"></a><b>&#167;6. </b>There's a tricky race condition here: the activity list has to be parsed
with the correct rulebook variables or it won't parse; but the rulebook
variables won't be known until the rule is booked; and in order to book the
rule, Inform needs to sort it into logical sequence with others already in the
same rulebook; and that requires knowledge of the conditions of usage; which
in turn requires the activity list. So the following function is called at the
last possible moment in the booking process.
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="reserved-syntax">void</span><span class="plain-syntax"> </span><span class="function-syntax">RuntimeContextData::ensure_avl</span><button class="popup" onclick="togglePopup('usagePopup5')"><span class="comment-syntax">?</span><span class="popuptext" id="usagePopup5">Usage of <span class="code-font"><span class="function-syntax">RuntimeContextData::ensure_avl</span></span>:<br/>Rulebooks - <a href="6-rlb.html#SP12">&#167;12</a></span></button><span class="plain-syntax">(</span><span class="reserved-syntax">rule</span><span class="plain-syntax"> *</span><span class="identifier-syntax">R</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">imperative_defn</span><span class="plain-syntax"> *</span><span class="identifier-syntax">id</span><span class="plain-syntax"> = </span><a href="6-rls.html#SP9" class="function-link"><span class="function-syntax">Rules::get_imperative_definition</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">R</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">id</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">id_body</span><span class="plain-syntax"> *</span><span class="identifier-syntax">idb</span><span class="plain-syntax"> = </span><span class="identifier-syntax">id</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">body_of_defn</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">id_runtime_context_data</span><span class="plain-syntax"> *</span><span class="identifier-syntax">rcd</span><span class="plain-syntax"> = &amp;(</span><span class="identifier-syntax">idb</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">runtime_context_data</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">Wordings::nonempty</span><span class="plain-syntax">(</span><span class="identifier-syntax">rcd</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">activity_context</span><span class="plain-syntax">)) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">parse_node</span><span class="plain-syntax"> *</span><span class="identifier-syntax">save_cs</span><span class="plain-syntax"> = </span><span class="identifier-syntax">current_sentence</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">current_sentence</span><span class="plain-syntax"> = </span><span class="identifier-syntax">id</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">at</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">stack_frame</span><span class="plain-syntax"> *</span><span class="identifier-syntax">phsf</span><span class="plain-syntax"> = &amp;(</span><span class="identifier-syntax">idb</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">compilation_data</span><span class="plain-syntax">.</span><span class="identifier-syntax">id_stack_frame</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">Frames::make_current</span><span class="plain-syntax">(</span><span class="identifier-syntax">phsf</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">Frames::set_shared_variable_access_list</span><span class="plain-syntax">(</span><span class="identifier-syntax">phsf</span><span class="plain-syntax">, </span><span class="identifier-syntax">R</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">variables_visible_in_definition</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">rcd</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">avl</span><span class="plain-syntax"> = </span><a href="5-rcd.html#SP7" class="function-link"><span class="function-syntax">RuntimeContextData::parse_avl</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">rcd</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">activity_context</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">current_sentence</span><span class="plain-syntax"> = </span><span class="identifier-syntax">save_cs</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax">}</span>
</pre>
<p class="commentary firstcommentary"><a id="SP7" class="paragraph-anchor"></a><b>&#167;7. </b>Which calls down to:
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="reserved-syntax">int</span><span class="plain-syntax"> </span><span class="identifier-syntax">parsing_al_conditions</span><span class="plain-syntax"> = </span><span class="identifier-syntax">TRUE</span><span class="plain-syntax">;</span>
<span class="reserved-syntax">activity_list</span><span class="plain-syntax"> *</span><span class="function-syntax">RuntimeContextData::parse_avl</span><button class="popup" onclick="togglePopup('usagePopup6')"><span class="comment-syntax">?</span><span class="popuptext" id="usagePopup6">Usage of <span class="code-font"><span class="function-syntax">RuntimeContextData::parse_avl</span></span>:<br/><a href="5-rcd.html#SP6">&#167;6</a></span></button><span class="plain-syntax">(</span><span class="identifier-syntax">wording</span><span class="plain-syntax"> </span><span class="identifier-syntax">W</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">int</span><span class="plain-syntax"> </span><span class="identifier-syntax">save_pac</span><span class="plain-syntax"> = </span><span class="identifier-syntax">parsing_al_conditions</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">parsing_al_conditions</span><span class="plain-syntax"> = </span><span class="identifier-syntax">TRUE</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">int</span><span class="plain-syntax"> </span><span class="identifier-syntax">rv</span><span class="plain-syntax"> = </span><span class="function-syntax">&lt;run-time-context&gt;</span><span class="plain-syntax">(</span><span class="identifier-syntax">W</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">parsing_al_conditions</span><span class="plain-syntax"> = </span><span class="identifier-syntax">save_pac</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">rv</span><span class="plain-syntax">) </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="function-syntax">&lt;&lt;rp&gt;&gt;</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="identifier-syntax">NULL</span><span class="plain-syntax">;</span>
<span class="plain-syntax">}</span>
</pre>
<p class="commentary firstcommentary"><a id="SP8" class="paragraph-anchor"></a><b>&#167;8. </b>Which in turn uses the following Preform grammar.
</p>
<p class="commentary">The direct handling of "something" below is to avoid Inform from reading it
as "some thing", with the implication that a <span class="extract"><span class="extract-syntax">K_thing</span></span> value is meant. When
people talk about "factorising something", where "factorising" is an activity
on numbers, for example, they mean "something" to stand for "any number", not
for "any physical object". Kind-checking means that only a number is possible
anyway, so we can safely just ignore the word "something".
</p>
<pre class="Preform-displayed-code all-displayed-code code-font">
<span class="Preform-function-syntax">&lt;run-time-context&gt;</span><span class="Preform-plain-syntax"> </span><span class="Preform-reserved-syntax">::=</span>
<span class="Preform-plain-syntax"> </span><span class="Preform-constant-syntax">not</span><span class="Preform-plain-syntax"> </span><span class="Preform-function-syntax">&lt;activity-list-unnegated&gt;</span><span class="Preform-plain-syntax"> </span><span class="Preform-reserved-syntax">|</span><span class="Preform-plain-syntax"> </span><span class="Preform-reserved-syntax">==&gt;</span><span class="Preform-plain-syntax"> { 0, RP[1] }; </span><span class="named-paragraph-container code-font"><a href="5-rcd.html#SP8_1" class="named-paragraph-link"><span class="named-paragraph">Flip the activity list parities</span><span class="named-paragraph-number">8.1</span></a></span><span class="Preform-constant-syntax">;</span>
<span class="Preform-plain-syntax"> </span><span class="Preform-function-syntax">&lt;activity-list-unnegated&gt;</span><span class="Preform-plain-syntax"> </span><span class="Preform-reserved-syntax">==&gt;</span><span class="Preform-plain-syntax"> { 0, RP[1] }</span>
<span class="Preform-function-syntax">&lt;activity-list-unnegated&gt;</span><span class="Preform-plain-syntax"> </span><span class="Preform-reserved-syntax">::=</span>
<span class="Preform-plain-syntax"> </span><span class="Preform-reserved-syntax">...</span><span class="Preform-plain-syntax"> </span><span class="Preform-reserved-syntax">|</span><span class="Preform-plain-syntax"> </span><span class="Preform-reserved-syntax">==&gt;</span><span class="Preform-plain-syntax"> { lookahead }</span>
<span class="Preform-plain-syntax"> </span><span class="Preform-function-syntax">&lt;activity-list-entry&gt;</span><span class="Preform-plain-syntax"> </span><span class="Preform-function-syntax">&lt;activity-tail&gt;</span><span class="Preform-plain-syntax"> </span><span class="Preform-reserved-syntax">|</span><span class="Preform-plain-syntax"> </span><span class="Preform-reserved-syntax">==&gt;</span><span class="Preform-plain-syntax"> </span><span class="named-paragraph-container code-font"><a href="5-rcd.html#SP8_2" class="named-paragraph-link"><span class="named-paragraph">Join the activity lists</span><span class="named-paragraph-number">8.2</span></a></span><span class="Preform-constant-syntax">;</span>
<span class="Preform-plain-syntax"> </span><span class="Preform-function-syntax">&lt;activity-list-entry&gt;</span><span class="Preform-plain-syntax"> </span><span class="Preform-reserved-syntax">==&gt;</span><span class="Preform-plain-syntax"> { 0, RP[1] }</span>
<span class="Preform-function-syntax">&lt;activity-tail&gt;</span><span class="Preform-plain-syntax"> </span><span class="Preform-reserved-syntax">::=</span>
<span class="Preform-plain-syntax"> </span><span class="Preform-constant-syntax">,</span><span class="Preform-plain-syntax"> </span><span class="Preform-constant-syntax">_or</span><span class="Preform-plain-syntax"> </span><span class="Preform-function-syntax">&lt;run-time-context&gt;</span><span class="Preform-plain-syntax"> </span><span class="Preform-reserved-syntax">|</span><span class="Preform-plain-syntax"> </span><span class="Preform-reserved-syntax">==&gt;</span><span class="Preform-plain-syntax"> { 0, RP[1] }</span>
<span class="Preform-plain-syntax"> </span><span class="Preform-constant-syntax">_,/or</span><span class="Preform-plain-syntax"> </span><span class="Preform-function-syntax">&lt;run-time-context&gt;</span><span class="Preform-plain-syntax"> </span><span class="Preform-reserved-syntax">==&gt;</span><span class="Preform-plain-syntax"> { 0, RP[1] }</span>
<span class="Preform-function-syntax">&lt;activity-list-entry&gt;</span><span class="Preform-plain-syntax"> </span><span class="Preform-reserved-syntax">::=</span>
<span class="Preform-plain-syntax"> </span><span class="Preform-function-syntax">&lt;activity-name&gt;</span><span class="Preform-plain-syntax"> </span><span class="Preform-reserved-syntax">|</span><span class="Preform-plain-syntax"> </span><span class="Preform-reserved-syntax">==&gt;</span><span class="Preform-plain-syntax"> </span><span class="named-paragraph-container code-font"><a href="5-rcd.html#SP8_3" class="named-paragraph-link"><span class="named-paragraph">Make one-entry AL without operand</span><span class="named-paragraph-number">8.3</span></a></span>
<span class="Preform-plain-syntax"> </span><span class="Preform-function-syntax">&lt;activity-name&gt;</span><span class="Preform-plain-syntax"> </span><span class="Preform-constant-syntax">of/for</span><span class="Preform-plain-syntax"> </span><span class="Preform-function-syntax">&lt;activity-operand&gt;</span><span class="Preform-plain-syntax"> </span><span class="Preform-reserved-syntax">|</span><span class="Preform-plain-syntax"> </span><span class="Preform-reserved-syntax">==&gt;</span><span class="Preform-plain-syntax"> </span><span class="named-paragraph-container code-font"><a href="5-rcd.html#SP8_4" class="named-paragraph-link"><span class="named-paragraph">Make one-entry AL with operand</span><span class="named-paragraph-number">8.4</span></a></span>
<span class="Preform-plain-syntax"> </span><span class="Preform-function-syntax">&lt;activity-name&gt;</span><span class="Preform-plain-syntax"> </span><span class="Preform-function-syntax">&lt;activity-operand&gt;</span><span class="Preform-plain-syntax"> </span><span class="Preform-reserved-syntax">|</span><span class="Preform-plain-syntax"> </span><span class="Preform-reserved-syntax">==&gt;</span><span class="Preform-plain-syntax"> </span><span class="named-paragraph-container code-font"><a href="5-rcd.html#SP8_4" class="named-paragraph-link"><span class="named-paragraph">Make one-entry AL with operand</span><span class="named-paragraph-number">8.4</span></a></span>
<span class="Preform-plain-syntax"> </span><span class="Preform-constant-syntax">^&lt;if-parsing-al-conditions&gt;</span><span class="Preform-plain-syntax"> </span><span class="Preform-reserved-syntax">...</span><span class="Preform-plain-syntax"> </span><span class="Preform-reserved-syntax">|</span><span class="Preform-plain-syntax"> </span><span class="Preform-reserved-syntax">==&gt;</span><span class="Preform-plain-syntax"> </span><span class="named-paragraph-container code-font"><a href="5-rcd.html#SP8_5" class="named-paragraph-link"><span class="named-paragraph">Make one-entry AL with unparsed text</span><span class="named-paragraph-number">8.5</span></a></span>
<span class="Preform-plain-syntax"> </span><span class="Preform-function-syntax">&lt;if-parsing-al-conditions&gt;</span><span class="Preform-plain-syntax"> </span><span class="Preform-function-syntax">&lt;s-condition&gt;</span><span class="Preform-plain-syntax"> </span><span class="Preform-reserved-syntax">==&gt;</span><span class="Preform-plain-syntax"> </span><span class="named-paragraph-container code-font"><a href="5-rcd.html#SP8_6" class="named-paragraph-link"><span class="named-paragraph">Make one-entry AL with condition</span><span class="named-paragraph-number">8.6</span></a></span>
<span class="Preform-function-syntax">&lt;activity-operand&gt;</span><span class="Preform-plain-syntax"> </span><span class="Preform-reserved-syntax">::=</span>
<span class="Preform-plain-syntax"> </span><span class="Preform-constant-syntax">something/anything</span><span class="Preform-plain-syntax"> </span><span class="Preform-reserved-syntax">|</span><span class="Preform-plain-syntax"> </span><span class="Preform-reserved-syntax">==&gt;</span><span class="Preform-plain-syntax"> { FALSE, Specifications::new_UNKNOWN(W) }</span>
<span class="Preform-plain-syntax"> </span><span class="Preform-constant-syntax">something/anything</span><span class="Preform-plain-syntax"> </span><span class="Preform-constant-syntax">else</span><span class="Preform-plain-syntax"> </span><span class="Preform-reserved-syntax">|</span><span class="Preform-plain-syntax"> </span><span class="Preform-reserved-syntax">==&gt;</span><span class="Preform-plain-syntax"> { FALSE, Specifications::new_UNKNOWN(W) }</span>
<span class="Preform-plain-syntax"> </span><span class="Preform-function-syntax">&lt;s-type-expression-or-value&gt;</span><span class="Preform-plain-syntax"> </span><span class="Preform-reserved-syntax">==&gt;</span><span class="Preform-plain-syntax"> { TRUE, RP[1] }</span>
<span class="Preform-function-syntax">&lt;if-parsing-al-conditions&gt;</span><span class="Preform-plain-syntax"> </span><span class="Preform-constant-syntax">internal</span><span class="Preform-plain-syntax"> </span><span class="Preform-constant-syntax">0</span><span class="Preform-plain-syntax"> </span><span class="Preform-constant-syntax">{</span>
<span class="Preform-plain-syntax"> </span><span class="Preform-reserved-syntax">if</span><span class="Preform-plain-syntax"> (</span><span class="Preform-identifier-syntax">parsing_al_conditions</span><span class="Preform-plain-syntax">) </span><span class="Preform-reserved-syntax">return</span><span class="Preform-plain-syntax"> </span><span class="Preform-identifier-syntax">TRUE</span><span class="Preform-plain-syntax">;</span>
<span class="Preform-plain-syntax"> ==&gt; { </span><span class="Preform-identifier-syntax">fail</span><span class="Preform-plain-syntax"> </span><span class="Preform-identifier-syntax">nonterminal</span><span class="Preform-plain-syntax"> };</span>
<span class="Preform-plain-syntax">}</span>
</pre>
<ul class="endnotetexts"><li>This is <a href="../words-module/4-ap.html" class="internal">Preform grammar</a>, not regular C code.</li></ul>
<p class="commentary firstcommentary"><a id="SP8_1" class="paragraph-anchor"></a><b>&#167;8.1. </b><span class="named-paragraph-container code-font"><span class="named-paragraph-defn">Flip the activity list parities</span><span class="named-paragraph-number">8.1</span></span><span class="Preform-comment-syntax"> =</span>
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="plain-syntax"> </span><span class="reserved-syntax">activity_list</span><span class="plain-syntax"> *</span><span class="identifier-syntax">al</span><span class="plain-syntax"> = *</span><span class="identifier-syntax">XP</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">for</span><span class="plain-syntax"> (; </span><span class="identifier-syntax">al</span><span class="plain-syntax">; </span><span class="identifier-syntax">al</span><span class="plain-syntax">=</span><span class="identifier-syntax">al</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">next</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">al</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">ACL_parity</span><span class="plain-syntax"> = (</span><span class="identifier-syntax">al</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">ACL_parity</span><span class="plain-syntax">)?</span><span class="identifier-syntax">FALSE:TRUE</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> }</span>
</pre>
<ul class="endnotetexts"><li>This code is used in <a href="5-rcd.html#SP8">&#167;8</a>.</li></ul>
<p class="commentary firstcommentary"><a id="SP8_2" class="paragraph-anchor"></a><b>&#167;8.2. </b><span class="named-paragraph-container code-font"><span class="named-paragraph-defn">Join the activity lists</span><span class="named-paragraph-number">8.2</span></span><span class="comment-syntax"> =</span>
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="plain-syntax"> </span><span class="reserved-syntax">activity_list</span><span class="plain-syntax"> *</span><span class="identifier-syntax">al1</span><span class="plain-syntax"> = </span><span class="identifier-syntax">RP</span><span class="plain-syntax">[1], *</span><span class="identifier-syntax">al2</span><span class="plain-syntax"> = </span><span class="identifier-syntax">RP</span><span class="plain-syntax">[2];</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">al1</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">next</span><span class="plain-syntax"> = </span><span class="identifier-syntax">al2</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> ==&gt; { -, </span><span class="identifier-syntax">al1</span><span class="plain-syntax"> };</span>
</pre>
<ul class="endnotetexts"><li>This code is used in <a href="5-rcd.html#SP8">&#167;8</a>.</li></ul>
<p class="commentary firstcommentary"><a id="SP8_3" class="paragraph-anchor"></a><b>&#167;8.3. </b><span class="named-paragraph-container code-font"><span class="named-paragraph-defn">Make one-entry AL without operand</span><span class="named-paragraph-number">8.3</span></span><span class="comment-syntax"> =</span>
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="plain-syntax"> </span><span class="reserved-syntax">activity_list</span><span class="plain-syntax"> *</span><span class="identifier-syntax">al</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="named-paragraph-container code-font"><a href="5-rcd.html#SP8_3_1" class="named-paragraph-link"><span class="named-paragraph">Make one-entry AL</span><span class="named-paragraph-number">8.3.1</span></a></span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">al</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">activity</span><span class="plain-syntax"> = </span><span class="identifier-syntax">RP</span><span class="plain-syntax">[1];</span>
</pre>
<ul class="endnotetexts"><li>This code is used in <a href="5-rcd.html#SP8">&#167;8</a>.</li></ul>
<p class="commentary firstcommentary"><a id="SP8_4" class="paragraph-anchor"></a><b>&#167;8.4. </b><span class="named-paragraph-container code-font"><span class="named-paragraph-defn">Make one-entry AL with operand</span><span class="named-paragraph-number">8.4</span></span><span class="comment-syntax"> =</span>
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="plain-syntax"> </span><span class="reserved-syntax">activity</span><span class="plain-syntax"> *</span><span class="identifier-syntax">an</span><span class="plain-syntax"> = </span><span class="identifier-syntax">RP</span><span class="plain-syntax">[1];</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">an</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">activity_on_what_kind</span><span class="plain-syntax"> == </span><span class="identifier-syntax">NULL</span><span class="plain-syntax">) </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="identifier-syntax">FALSE</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> ((</span><span class="identifier-syntax">R</span><span class="plain-syntax">[2]) &amp;&amp; (</span><span class="identifier-syntax">Dash::validate_parameter</span><span class="plain-syntax">(</span><span class="identifier-syntax">RP</span><span class="plain-syntax">[2], </span><span class="identifier-syntax">an</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">activity_on_what_kind</span><span class="plain-syntax">) == </span><span class="identifier-syntax">FALSE</span><span class="plain-syntax">))</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="identifier-syntax">FALSE</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">activity_list</span><span class="plain-syntax"> *</span><span class="identifier-syntax">al</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="named-paragraph-container code-font"><a href="5-rcd.html#SP8_3_1" class="named-paragraph-link"><span class="named-paragraph">Make one-entry AL</span><span class="named-paragraph-number">8.3.1</span></a></span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">al</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">activity</span><span class="plain-syntax"> = </span><span class="identifier-syntax">an</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">al</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">acting_on</span><span class="plain-syntax"> = </span><span class="identifier-syntax">RP</span><span class="plain-syntax">[2];</span>
</pre>
<ul class="endnotetexts"><li>This code is used in <a href="5-rcd.html#SP8">&#167;8</a> (twice).</li></ul>
<p class="commentary firstcommentary"><a id="SP8_5" class="paragraph-anchor"></a><b>&#167;8.5. </b><span class="named-paragraph-container code-font"><span class="named-paragraph-defn">Make one-entry AL with unparsed text</span><span class="named-paragraph-number">8.5</span></span><span class="comment-syntax"> =</span>
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="plain-syntax"> </span><span class="identifier-syntax">parse_node</span><span class="plain-syntax"> *</span><span class="identifier-syntax">cond</span><span class="plain-syntax"> = </span><span class="identifier-syntax">Specifications::new_UNKNOWN</span><span class="plain-syntax">(</span><span class="identifier-syntax">EMPTY_WORDING</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">activity_list</span><span class="plain-syntax"> *</span><span class="identifier-syntax">al</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="named-paragraph-container code-font"><a href="5-rcd.html#SP8_3_1" class="named-paragraph-link"><span class="named-paragraph">Make one-entry AL</span><span class="named-paragraph-number">8.3.1</span></a></span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">al</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">only_when</span><span class="plain-syntax"> = </span><span class="identifier-syntax">cond</span><span class="plain-syntax">;</span>
</pre>
<ul class="endnotetexts"><li>This code is used in <a href="5-rcd.html#SP8">&#167;8</a>.</li></ul>
<p class="commentary firstcommentary"><a id="SP8_6" class="paragraph-anchor"></a><b>&#167;8.6. </b><span class="named-paragraph-container code-font"><span class="named-paragraph-defn">Make one-entry AL with condition</span><span class="named-paragraph-number">8.6</span></span><span class="comment-syntax"> =</span>
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="plain-syntax"> </span><span class="identifier-syntax">parse_node</span><span class="plain-syntax"> *</span><span class="identifier-syntax">cond</span><span class="plain-syntax"> = </span><span class="identifier-syntax">RP</span><span class="plain-syntax">[2];</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">Dash::validate_conditional_clause</span><span class="plain-syntax">(</span><span class="identifier-syntax">cond</span><span class="plain-syntax">) == </span><span class="identifier-syntax">FALSE</span><span class="plain-syntax">) </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="identifier-syntax">FALSE</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">activity_list</span><span class="plain-syntax"> *</span><span class="identifier-syntax">al</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="named-paragraph-container code-font"><a href="5-rcd.html#SP8_3_1" class="named-paragraph-link"><span class="named-paragraph">Make one-entry AL</span><span class="named-paragraph-number">8.3.1</span></a></span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">al</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">only_when</span><span class="plain-syntax"> = </span><span class="identifier-syntax">cond</span><span class="plain-syntax">;</span>
</pre>
<ul class="endnotetexts"><li>This code is used in <a href="5-rcd.html#SP8">&#167;8</a>.</li></ul>
<p class="commentary firstcommentary"><a id="SP8_3_1" class="paragraph-anchor"></a><b>&#167;8.3.1. </b><span class="named-paragraph-container code-font"><span class="named-paragraph-defn">Make one-entry AL</span><span class="named-paragraph-number">8.3.1</span></span><span class="comment-syntax"> =</span>
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="plain-syntax"> </span><span class="identifier-syntax">al</span><span class="plain-syntax"> = </span><span class="identifier-syntax">CREATE</span><span class="plain-syntax">(</span><span class="reserved-syntax">activity_list</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">al</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">acting_on</span><span class="plain-syntax"> = </span><span class="identifier-syntax">NULL</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">al</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">only_when</span><span class="plain-syntax"> = </span><span class="identifier-syntax">NULL</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">al</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">next</span><span class="plain-syntax"> = </span><span class="identifier-syntax">NULL</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">al</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">ACL_parity</span><span class="plain-syntax"> = </span><span class="identifier-syntax">TRUE</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">al</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">activity</span><span class="plain-syntax"> = </span><span class="identifier-syntax">NULL</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> ==&gt; { -, </span><span class="identifier-syntax">al</span><span class="plain-syntax"> };</span>
</pre>
<ul class="endnotetexts"><li>This code is used in <a href="5-rcd.html#SP8_3">&#167;8.3</a>, <a href="5-rcd.html#SP8_4">&#167;8.4</a>, <a href="5-rcd.html#SP8_5">&#167;8.5</a>, <a href="5-rcd.html#SP8_6">&#167;8.6</a>.</li></ul>
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