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<ul class="crumbs"><li><a href="../index.html">Home</a></li><li><a href="../compiler.html">Inform7</a></li><li><a href="index.html">imperative</a></li><li><a href="index.html#4">Chapter 4: Propositions</a></li><li><b>Cinders and Deferrals</b></li></ul></div>
<p class="purpose">Cinders are constants in deferred propositions referring to values in the original stack frame.</p>
<ul class="toc"><li><a href="4-cad.html#SP7">&#167;7. The kind of terms</a></li></ul><hr class="tocbar">
<p class="commentary firstcommentary"><a id="SP1" class="paragraph-anchor"></a><b>&#167;1. </b>The issues giving rise to cinders are explained in <a href="4-dtd.html" class="internal">Deciding to Defer</a>.
When a proposition contains a constant &mdash; in the predicate calculus sense;
it may well be a variable or even a function call in Inform &mdash; and this
cannot be accessed from the stack frame of the proposition's deferral
function, the constant is a "cinder".<sup id="fnref:1"><a href="#fn:1" rel="footnote">1</a></sup>
</p>
<p class="commentary">Clearly genuine constants &mdash; literal numbers, names of rules, and so on &mdash; and
global variables need not be cindered: those are the same in any stack frame
and can be evaluated without side-effects. We cinder everything else, which
seems only prudent. For example:
</p>
<ul class="items"><li>(a) phrases to decide values, cindered because they might be slow or have
side-effects to evaluate;
</li><li>(b) shared non-local variables, such as variables attached to actions or
activities, cindered because they are only allowed in certain routines, and
the eventual deferred proposition routine might not qualify;
</li><li>(c) local variables, cindered since they won't exist in the deferred routine;
</li><li>(d) list and table entries, cindered since they are relatively slow to look up.
</li></ul>
<ul class="footnotetexts"><li class="footnote" id="fn:1"><p class="inwebfootnote"><sup id="fnref:1"><a href="#fn:1" rel="footnote">1</a></sup> Originally a contraction of "constant in deferred routine".
<a href="#fnref:1" title="return to text"> &#x21A9;</a></p></li></ul>
<pre class="displayed-code all-displayed-code code-font">
<span class="reserved-syntax">int</span><span class="plain-syntax"> </span><span class="function-syntax">Cinders::needs_to_be_cindered</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">Cinders::needs_to_be_cindered</span></span>:<br/><a href="4-cad.html#SP3">&#167;3</a>, <a href="4-cad.html#SP4">&#167;4</a></span></button><span class="plain-syntax">(</span><span class="identifier-syntax">parse_node</span><span class="plain-syntax"> *</span><span class="identifier-syntax">spec</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">Node::is</span><span class="plain-syntax">(</span><span class="identifier-syntax">spec</span><span class="plain-syntax">, </span><span class="identifier-syntax">CONSTANT_NT</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">Lvalues::is_global_variable</span><span class="plain-syntax">(</span><span class="identifier-syntax">spec</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">return</span><span class="plain-syntax"> </span><span class="identifier-syntax">TRUE</span><span class="plain-syntax">;</span>
<span class="plain-syntax">}</span>
</pre>
<p class="commentary firstcommentary"><a id="SP2" class="paragraph-anchor"></a><b>&#167;2. </b>At any given moment, we can only be working on the compilation of a single
deferred proposition function, so we store its identity in the following
rather than waste space giving each <span class="extract"><span class="extract-syntax">pcalc_term</span></span> a pointer to it:
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="reserved-syntax">pcalc_prop_deferral</span><span class="plain-syntax"> *</span><span class="identifier-syntax">current_pdef</span><span class="plain-syntax"> = </span><span class="identifier-syntax">NULL</span><span class="plain-syntax">; </span><span class="comment-syntax"> used only in this section</span>
</pre>
<p class="commentary firstcommentary"><a id="SP3" class="paragraph-anchor"></a><b>&#167;3. </b>Within any given proposition, the cinders are numbered 0, 1, 2, ...; these
numbers are recorded in the <span class="extract"><span class="extract-syntax">cinder</span></span> field of the relevant <span class="extract"><span class="extract-syntax">pcalc_term</span></span> structure.
A term with <span class="extract"><span class="extract-syntax">cinder</span></span> set to \(-1\) is not a cinder.
</p>
<p class="commentary">Here we count the cinders in a proposition, but compile nothing and change nothing:
</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">Cinders::count</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">Cinders::count</span></span>:<br/>Compile Loops - <a href="4-cl.html#SP2">&#167;2</a><br/>Deciding to Defer - <a href="4-dtd.html#SP11">&#167;11</a></span></button><span class="plain-syntax">(</span><span class="identifier-syntax">pcalc_prop</span><span class="plain-syntax"> *</span><span class="identifier-syntax">prop</span><span class="plain-syntax">, </span><span class="reserved-syntax">pcalc_prop_deferral</span><span class="plain-syntax"> *</span><span class="identifier-syntax">pdef</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="identifier-syntax">TRAVERSE_VARIABLE</span><span class="plain-syntax">(</span><span class="identifier-syntax">atom</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">TRAVERSE_PROPOSITION</span><span class="plain-syntax">(</span><span class="identifier-syntax">atom</span><span class="plain-syntax">, </span><span class="identifier-syntax">prop</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="function-syntax">&lt;atom-&gt;</span><span class="identifier-syntax">arity</span><span class="plain-syntax">; </span><span class="identifier-syntax">i</span><span class="plain-syntax">++)</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">N</span><span class="plain-syntax"> = </span><a href="4-cad.html#SP3" class="function-link"><span class="function-syntax">Cinders::count_in_term</span></a><span class="plain-syntax">(&amp;(</span><span class="identifier-syntax">atom</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">terms</span><span class="plain-syntax">[</span><span class="identifier-syntax">i</span><span class="plain-syntax">]), </span><span class="identifier-syntax">N</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>
<span class="reserved-syntax">int</span><span class="plain-syntax"> </span><span class="function-syntax">Cinders::count_in_term</span><span class="plain-syntax">(</span><span class="identifier-syntax">pcalc_term</span><span class="plain-syntax"> *</span><span class="identifier-syntax">pt</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="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">pt</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">function</span><span class="plain-syntax">) </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><a href="4-cad.html#SP3" class="function-link"><span class="function-syntax">Cinders::count_in_term</span></a><span class="plain-syntax">(&amp;(</span><span class="identifier-syntax">pt</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">function</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">fn_of</span><span class="plain-syntax">), </span><span class="identifier-syntax">N</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">pt</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">constant</span><span class="plain-syntax">)</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><a href="4-cad.html#SP1" class="function-link"><span class="function-syntax">Cinders::needs_to_be_cindered</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">pt</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">constant</span><span class="plain-syntax">))</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">N</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="SP4" class="paragraph-anchor"></a><b>&#167;4. </b>This more ambitious function sets the <span class="extract"><span class="extract-syntax">cinder</span></span> field for each term, and also
sets the kinds of the cinder values in the deferred function.
</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">Cinders::compile_cindered_values</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">Cinders::compile_cindered_values</span></span>:<br/>Compile Loops - <a href="4-cl.html#SP2">&#167;2</a><br/>Deciding to Defer - <a href="4-dtd.html#SP4_2">&#167;4.2</a>, <a href="4-dtd.html#SP10">&#167;10</a>, <a href="4-dtd.html#SP11">&#167;11</a></span></button><span class="plain-syntax">(</span><span class="identifier-syntax">pcalc_prop</span><span class="plain-syntax"> *</span><span class="identifier-syntax">prop</span><span class="plain-syntax">, </span><span class="reserved-syntax">pcalc_prop_deferral</span><span class="plain-syntax"> *</span><span class="identifier-syntax">pdef</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">pcalc_prop_deferral</span><span class="plain-syntax"> *</span><span class="identifier-syntax">save_current_pdef</span><span class="plain-syntax"> = </span><span class="identifier-syntax">current_pdef</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">current_pdef</span><span class="plain-syntax"> = </span><span class="identifier-syntax">pdef</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="identifier-syntax">TRAVERSE_VARIABLE</span><span class="plain-syntax">(</span><span class="identifier-syntax">atom</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">TRAVERSE_PROPOSITION</span><span class="plain-syntax">(</span><span class="identifier-syntax">atom</span><span class="plain-syntax">, </span><span class="identifier-syntax">prop</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="function-syntax">&lt;atom-&gt;</span><span class="identifier-syntax">arity</span><span class="plain-syntax">; </span><span class="identifier-syntax">i</span><span class="plain-syntax">++)</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">N</span><span class="plain-syntax"> = </span><a href="4-cad.html#SP4" class="function-link"><span class="function-syntax">Cinders::compile_cindered_value_in_term</span></a><span class="plain-syntax">(&amp;(</span><span class="identifier-syntax">atom</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">terms</span><span class="plain-syntax">[</span><span class="identifier-syntax">i</span><span class="plain-syntax">]), </span><span class="identifier-syntax">N</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">current_pdef</span><span class="plain-syntax"> = </span><span class="identifier-syntax">save_current_pdef</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>
<span class="reserved-syntax">int</span><span class="plain-syntax"> </span><span class="function-syntax">Cinders::compile_cindered_value_in_term</span><span class="plain-syntax">(</span><span class="identifier-syntax">pcalc_term</span><span class="plain-syntax"> *</span><span class="identifier-syntax">pt</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="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">pt</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">function</span><span class="plain-syntax">)</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><a href="4-cad.html#SP4" class="function-link"><span class="function-syntax">Cinders::compile_cindered_value_in_term</span></a><span class="plain-syntax">(&amp;(</span><span class="identifier-syntax">pt</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">function</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">fn_of</span><span class="plain-syntax">), </span><span class="identifier-syntax">N</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">pt</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">constant</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><a href="4-cad.html#SP1" class="function-link"><span class="function-syntax">Cinders::needs_to_be_cindered</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">pt</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">constant</span><span class="plain-syntax">)) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">pt</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">cinder</span><span class="plain-syntax"> = </span><span class="identifier-syntax">N</span><span class="plain-syntax">++;</span>
<span class="plain-syntax"> </span><a href="2-cv.html#SP5" class="function-link"><span class="function-syntax">CompileValues::to_code_val</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">pt</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">constant</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">current_pdef</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">cinder_kinds</span><span class="plain-syntax">[</span><span class="identifier-syntax">pt</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">cinder</span><span class="plain-syntax">] = </span><span class="identifier-syntax">Specifications::to_kind</span><span class="plain-syntax">(</span><span class="identifier-syntax">pt</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">constant</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> } </span><span class="reserved-syntax">else</span><span class="plain-syntax"> {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">pt</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">cinder</span><span class="plain-syntax"> = -1;</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="SP5" class="paragraph-anchor"></a><b>&#167;5. </b>Symmetrically, when we come to compiled our deferred proposition function,
we need to declare local variables to hold these cinders.
</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">Cinders::declare</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">Cinders::declare</span></span>:<br/>Compile Deferred Propositions - <a href="4-cdp.html#SP3_5">&#167;3.5</a></span></button><span class="plain-syntax">(</span><span class="identifier-syntax">pcalc_prop</span><span class="plain-syntax"> *</span><span class="identifier-syntax">prop</span><span class="plain-syntax">, </span><span class="reserved-syntax">pcalc_prop_deferral</span><span class="plain-syntax"> *</span><span class="identifier-syntax">pdef</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">pcalc_prop_deferral</span><span class="plain-syntax"> *</span><span class="identifier-syntax">save_current_pdef</span><span class="plain-syntax"> = </span><span class="identifier-syntax">current_pdef</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">current_pdef</span><span class="plain-syntax"> = </span><span class="identifier-syntax">pdef</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="identifier-syntax">TRAVERSE_VARIABLE</span><span class="plain-syntax">(</span><span class="identifier-syntax">atom</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">TRAVERSE_PROPOSITION</span><span class="plain-syntax">(</span><span class="identifier-syntax">atom</span><span class="plain-syntax">, </span><span class="identifier-syntax">prop</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="function-syntax">&lt;atom-&gt;</span><span class="identifier-syntax">arity</span><span class="plain-syntax">; </span><span class="identifier-syntax">i</span><span class="plain-syntax">++)</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">N</span><span class="plain-syntax"> = </span><a href="4-cad.html#SP5" class="function-link"><span class="function-syntax">Cinders::cind_declare_in_term</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">N</span><span class="plain-syntax">, &amp;(</span><span class="identifier-syntax">atom</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">terms</span><span class="plain-syntax">[</span><span class="identifier-syntax">i</span><span class="plain-syntax">]));</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">current_pdef</span><span class="plain-syntax"> = </span><span class="identifier-syntax">save_current_pdef</span><span class="plain-syntax">;</span>
<span class="plain-syntax">}</span>
<span class="reserved-syntax">int</span><span class="plain-syntax"> </span><span class="function-syntax">Cinders::cind_declare_in_term</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="identifier-syntax">pcalc_term</span><span class="plain-syntax"> *</span><span class="identifier-syntax">pt</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">pt</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">function</span><span class="plain-syntax">)</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><a href="4-cad.html#SP5" class="function-link"><span class="function-syntax">Cinders::cind_declare_in_term</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">N</span><span class="plain-syntax">, &amp;(</span><span class="identifier-syntax">pt</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">function</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">fn_of</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">pt</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">constant</span><span class="plain-syntax">) &amp;&amp; (</span><span class="identifier-syntax">pt</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">cinder</span><span class="plain-syntax"> &gt;= </span><span class="constant-syntax">0</span><span class="plain-syntax">)) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">TEMPORARY_TEXT</span><span class="plain-syntax">(</span><span class="identifier-syntax">cinder_name</span><span class="plain-syntax">)</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">WRITE_TO</span><span class="plain-syntax">(</span><span class="identifier-syntax">cinder_name</span><span class="plain-syntax">, </span><span class="string-syntax">"const_%d"</span><span class="plain-syntax">, </span><span class="identifier-syntax">N</span><span class="plain-syntax">++);</span>
<span class="plain-syntax"> </span><a href="3-lv.html#SP4" class="function-link"><span class="function-syntax">LocalVariables::new_other_as_symbol</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">cinder_name</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">DISCARD_TEXT</span><span class="plain-syntax">(</span><span class="identifier-syntax">cinder_name</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>Given, say, <span class="extract"><span class="extract-syntax">v == 2</span></span>, we return the local variable <span class="extract"><span class="extract-syntax">const_2</span></span> holding cindered
value 2. Speed is not critical here.
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="reserved-syntax">local_variable</span><span class="plain-syntax"> *</span><span class="function-syntax">Cinders::find_cinder_var</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">Cinders::find_cinder_var</span></span>:<br/>Compile Schemas - <a href="4-cs.html#SP5_2">&#167;5.2</a></span></button><span class="plain-syntax">(</span><span class="reserved-syntax">int</span><span class="plain-syntax"> </span><span class="identifier-syntax">v</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">TEMPORARY_TEXT</span><span class="plain-syntax">(</span><span class="identifier-syntax">T</span><span class="plain-syntax">)</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">WRITE_TO</span><span class="plain-syntax">(</span><span class="identifier-syntax">T</span><span class="plain-syntax">, </span><span class="string-syntax">"const_%d"</span><span class="plain-syntax">, </span><span class="identifier-syntax">v</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">local_variable</span><span class="plain-syntax"> *</span><span class="identifier-syntax">found</span><span class="plain-syntax"> = </span><a href="3-lv.html#SP13" class="function-link"><span class="function-syntax">LocalVariables::by_identifier</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">T</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">DISCARD_TEXT</span><span class="plain-syntax">(</span><span class="identifier-syntax">T</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">found</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. The kind of terms. </b>We are now finally able to say what the kind of value of a term to be
compiled is. The only troublesome case is when the term is a cinder; its
kind is then part of the information recorded at deferral time.
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="identifier-syntax">kind</span><span class="plain-syntax"> *</span><span class="function-syntax">Cinders::kind_of_term</span><span class="plain-syntax">(</span><span class="identifier-syntax">pcalc_term</span><span class="plain-syntax"> </span><span class="identifier-syntax">pt</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">pt</span><span class="plain-syntax">.</span><span class="identifier-syntax">variable</span><span class="plain-syntax"> &gt;= </span><span class="constant-syntax">0</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">pt</span><span class="plain-syntax">.</span><span class="identifier-syntax">term_checked_as_kind</span><span class="plain-syntax">) </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="identifier-syntax">pt</span><span class="plain-syntax">.</span><span class="identifier-syntax">term_checked_as_kind</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">K_object</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">pt</span><span class="plain-syntax">.</span><span class="identifier-syntax">constant</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">pt</span><span class="plain-syntax">.</span><span class="identifier-syntax">cinder</span><span class="plain-syntax"> &gt;= </span><span class="constant-syntax">0</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">current_pdef</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">internal_error</span><span class="plain-syntax">(</span><span class="string-syntax">"cindered term outside of deferral"</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">current_pdef</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">cinder_kinds</span><span class="plain-syntax">[</span><span class="identifier-syntax">pt</span><span class="plain-syntax">.</span><span class="identifier-syntax">cinder</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">Specifications::is_phrasal</span><span class="plain-syntax">(</span><span class="identifier-syntax">pt</span><span class="plain-syntax">.</span><span class="identifier-syntax">constant</span><span class="plain-syntax">))</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">Dash::check_value</span><span class="plain-syntax">(</span><span class="identifier-syntax">pt</span><span class="plain-syntax">.</span><span class="identifier-syntax">constant</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"> </span><span class="identifier-syntax">Specifications::to_kind</span><span class="plain-syntax">(</span><span class="identifier-syntax">pt</span><span class="plain-syntax">.</span><span class="identifier-syntax">constant</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">pt</span><span class="plain-syntax">.</span><span class="identifier-syntax">function</span><span class="plain-syntax">) </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="identifier-syntax">K_object</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="comment-syntax"> never reached, though compilers cannot prove that</span>
<span class="plain-syntax">}</span>
</pre>
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