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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">runtime</a></li><li><a href="index.html#5">Chapter 5: Provision Submodules</a></li><li><b>Variables</b></li></ul></div>
<p class="purpose">To compile the variables submodule for a compilation unit, which contains _variable packages.</p>
<ul class="toc"><li><a href="5-vrb.html#SP1">&#167;1. NVEs</a></li><li><a href="5-vrb.html#SP9">&#167;9. Writing without NVEs</a></li><li><a href="5-vrb.html#SP10">&#167;10. Compilation data</a></li><li><a href="5-vrb.html#SP13">&#167;13. Compilation</a></li><li><a href="5-vrb.html#SP15">&#167;15. Initial values</a></li></ul><hr class="tocbar">
<p class="commentary firstcommentary"><a id="SP1" class="paragraph-anchor"></a><b>&#167;1. NVEs. </b>While a nonlocal variable, or NLV, looks like a simple storage location from
the perspective of Inform 7 source text &mdash; the author assumes there's some
memory cell somewhere with this name &mdash; it can actually be data expressed in
a range of different ways in Inter code. It might indeed be a global variable,
but then again it might be an array entry, or even a temporary location on
a stack; it might even be a constant.
</p>
<p class="commentary">This range of possible expressions is represented by a <a href="5-vrb.html#SP1" class="internal">nonlocal_variable_emission</a>,
or NVE. Each variable in principle has two, a left and a right NVE, though in
practice they are often the same. The left NVE tells Inform how to compile
assignments to the variable (i.e., when using it as an lvalue); the right NVE
how to compile lookups of its value (i.e., as an rvalue).
</p>
<p class="commentary">The NVE structure looks messy, but it's basically a union of four possibilities,
of which the last is the default:
</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">nonlocal_variable_emission</span><span class="plain-syntax"> {</span>
<span class="plain-syntax"> </span><span class="comment-syntax"> access as this Inter constant or global variable</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">struct</span><span class="plain-syntax"> </span><span class="identifier-syntax">inter_name</span><span class="plain-syntax"> *</span><span class="identifier-syntax">iname_form</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="comment-syntax"> access as the Inter </span><span class="extract"><span class="extract-syntax">nothing</span></span><span class="comment-syntax"> constant</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">int</span><span class="plain-syntax"> </span><span class="identifier-syntax">nothing_form</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="comment-syntax"> access as this shared variable on the M-stack</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">struct</span><span class="plain-syntax"> </span><span class="identifier-syntax">inter_name</span><span class="plain-syntax"> *</span><span class="identifier-syntax">shv_set_ID</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">shv_index</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">allow_access_even_if_does_not_exist</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="comment-syntax"> access as the iname belonging to the NLV itself</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">int</span><span class="plain-syntax"> </span><span class="identifier-syntax">use_own_iname</span><span class="plain-syntax">;</span>
<span class="plain-syntax">} </span><span class="reserved-syntax">nonlocal_variable_emission</span><span class="plain-syntax">;</span>
</pre>
<ul class="endnotetexts"><li>The structure nonlocal_variable_emission is private to this section.</li></ul>
<p class="commentary firstcommentary"><a id="SP2" class="paragraph-anchor"></a><b>&#167;2. </b>The following is the default:
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="reserved-syntax">nonlocal_variable_emission</span><span class="plain-syntax"> </span><span class="function-syntax">RTVariables::default_nve</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">RTVariables::default_nve</span></span>:<br/><a href="5-vrb.html#SP3">&#167;3</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">nonlocal_variable_emission</span><span class="plain-syntax"> </span><span class="identifier-syntax">nve</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">nve</span><span class="plain-syntax">.</span><span class="element-syntax">iname_form</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">nve</span><span class="plain-syntax">.</span><span class="element-syntax">nothing_form</span><span class="plain-syntax"> = </span><span class="identifier-syntax">FALSE</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">nve</span><span class="plain-syntax">.</span><span class="element-syntax">shv_set_ID</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">nve</span><span class="plain-syntax">.</span><span class="element-syntax">shv_index</span><span class="plain-syntax"> = -1;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">nve</span><span class="plain-syntax">.</span><span class="element-syntax">allow_access_even_if_does_not_exist</span><span class="plain-syntax"> = </span><span class="identifier-syntax">FALSE</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">nve</span><span class="plain-syntax">.</span><span class="element-syntax">use_own_iname</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">nve</span><span class="plain-syntax">;</span>
<span class="plain-syntax">}</span>
</pre>
<p class="commentary firstcommentary"><a id="SP3" class="paragraph-anchor"></a><b>&#167;3. </b>So where do these NVEs come from?
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="reserved-syntax">nonlocal_variable_emission</span><span class="plain-syntax"> </span><span class="function-syntax">RTVariables::nve_from_nothing</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">RTVariables::nve_from_nothing</span></span>:<br/><a href="5-vrb.html#SP6">&#167;6</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">nonlocal_variable_emission</span><span class="plain-syntax"> </span><span class="identifier-syntax">nve</span><span class="plain-syntax"> = </span><a href="5-vrb.html#SP2" class="function-link"><span class="function-syntax">RTVariables::default_nve</span></a><span class="plain-syntax">();</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">nve</span><span class="plain-syntax">.</span><span class="element-syntax">nothing_form</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">return</span><span class="plain-syntax"> </span><span class="identifier-syntax">nve</span><span class="plain-syntax">;</span>
<span class="plain-syntax">}</span>
<span class="reserved-syntax">nonlocal_variable_emission</span><span class="plain-syntax"> </span><span class="function-syntax">RTVariables::nve_from_iname</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">RTVariables::nve_from_iname</span></span>:<br/><a href="5-vrb.html#SP5">&#167;5</a></span></button><span class="plain-syntax">(</span><span class="identifier-syntax">inter_name</span><span class="plain-syntax"> *</span><span class="identifier-syntax">iname</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">nonlocal_variable_emission</span><span class="plain-syntax"> </span><span class="identifier-syntax">nve</span><span class="plain-syntax"> = </span><a href="5-vrb.html#SP2" class="function-link"><span class="function-syntax">RTVariables::default_nve</span></a><span class="plain-syntax">();</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">nve</span><span class="plain-syntax">.</span><span class="element-syntax">iname_form</span><span class="plain-syntax"> = </span><span class="identifier-syntax">iname</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">nve</span><span class="plain-syntax">;</span>
<span class="plain-syntax">}</span>
<span class="reserved-syntax">nonlocal_variable_emission</span><span class="plain-syntax"> </span><span class="function-syntax">RTVariables::nve_from_mstack</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">RTVariables::nve_from_mstack</span></span>:<br/><a href="5-vrb.html#SP7">&#167;7</a></span></button><span class="plain-syntax">(</span><span class="identifier-syntax">inter_name</span><span class="plain-syntax"> *</span><span class="identifier-syntax">iname</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">index</span><span class="plain-syntax">, </span><span class="reserved-syntax">int</span><span class="plain-syntax"> </span><span class="identifier-syntax">allow_access_even_if_does_not_exist</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">nonlocal_variable_emission</span><span class="plain-syntax"> </span><span class="identifier-syntax">nve</span><span class="plain-syntax"> = </span><a href="5-vrb.html#SP2" class="function-link"><span class="function-syntax">RTVariables::default_nve</span></a><span class="plain-syntax">();</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">nve</span><span class="plain-syntax">.</span><span class="element-syntax">shv_set_ID</span><span class="plain-syntax"> = </span><span class="identifier-syntax">iname</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">nve</span><span class="plain-syntax">.</span><span class="element-syntax">shv_index</span><span class="plain-syntax"> = </span><span class="identifier-syntax">index</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">nve</span><span class="plain-syntax">.</span><span class="element-syntax">allow_access_even_if_does_not_exist</span><span class="plain-syntax"> = </span><span class="identifier-syntax">allow_access_even_if_does_not_exist</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">nve</span><span class="plain-syntax">;</span>
<span class="plain-syntax">}</span>
<span class="reserved-syntax">nonlocal_variable_emission</span><span class="plain-syntax"> </span><span class="function-syntax">RTVariables::nve_from_own_iname</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">RTVariables::nve_from_own_iname</span></span>:<br/><a href="5-vrb.html#SP10">&#167;10</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">nonlocal_variable_emission</span><span class="plain-syntax"> </span><span class="identifier-syntax">nve</span><span class="plain-syntax"> = </span><a href="5-vrb.html#SP2" class="function-link"><span class="function-syntax">RTVariables::default_nve</span></a><span class="plain-syntax">();</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">nve</span><span class="plain-syntax">.</span><span class="element-syntax">use_own_iname</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">return</span><span class="plain-syntax"> </span><span class="identifier-syntax">nve</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>As noted above, the left and right NVEs are usually the same:
</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">RTVariables::set_NVE</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">RTVariables::set_NVE</span></span>:<br/><a href="5-vrb.html#SP5">&#167;5</a>, <a href="5-vrb.html#SP6">&#167;6</a></span></button><span class="plain-syntax">(</span><span class="identifier-syntax">nonlocal_variable</span><span class="plain-syntax"> *</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">, </span><span class="reserved-syntax">nonlocal_variable_emission</span><span class="plain-syntax"> </span><span class="identifier-syntax">nve</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">nlv</span><span class="plain-syntax"> == </span><span class="identifier-syntax">NULL</span><span class="plain-syntax">) </span><span class="identifier-syntax">internal_error</span><span class="plain-syntax">(</span><span class="string-syntax">"null nlv"</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">compilation_data</span><span class="plain-syntax">.</span><span class="element-syntax">lvalue_nve</span><span class="plain-syntax"> = </span><span class="identifier-syntax">nve</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">compilation_data</span><span class="plain-syntax">.</span><span class="element-syntax">rvalue_nve</span><span class="plain-syntax"> = </span><span class="identifier-syntax">nve</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>This is a particularly useful case, where <span class="extract"><span class="extract-syntax">iname</span></span> can be the iname of a
constant or a global variable in Inter:
</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">RTVariables::store_in_this_iname</span><button class="popup" onclick="togglePopup('usagePopup7')"><span class="comment-syntax">?</span><span class="popuptext" id="usagePopup7">Usage of <span class="code-font"><span class="function-syntax">RTVariables::store_in_this_iname</span></span>:<br/><a href="5-vrb.html#SP6">&#167;6</a>, <a href="5-vrb.html#SP7">&#167;7</a></span></button><span class="plain-syntax">(</span><span class="identifier-syntax">nonlocal_variable</span><span class="plain-syntax"> *</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">, </span><span class="identifier-syntax">inter_name</span><span class="plain-syntax"> *</span><span class="identifier-syntax">iname</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><a href="5-vrb.html#SP4" class="function-link"><span class="function-syntax">RTVariables::set_NVE</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">, </span><a href="5-vrb.html#SP3" class="function-link"><span class="function-syntax">RTVariables::nve_from_iname</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">iname</span><span class="plain-syntax">));</span>
<span class="plain-syntax">}</span>
<span class="reserved-syntax">void</span><span class="plain-syntax"> </span><span class="function-syntax">RTVariables::understood_variable</span><span class="plain-syntax">(</span><span class="identifier-syntax">nonlocal_variable</span><span class="plain-syntax"> *</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><a href="5-vrb.html#SP5" class="function-link"><span class="function-syntax">RTVariables::store_in_this_iname</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">, </span><a href="2-hrr.html#SP11" class="function-link"><span class="function-syntax">Hierarchy::find</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">PARSED_NUMBER_HL</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>And in particular that's how we handle sentences like "Maximum score translates
into Inter as "MAX_SCORE".":
</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">RTVariables::identifier_translates</span><span class="plain-syntax">(</span><span class="identifier-syntax">nonlocal_variable</span><span class="plain-syntax"> *</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">, </span><span class="identifier-syntax">text_stream</span><span class="plain-syntax"> *</span><span class="identifier-syntax">name</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">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">compilation_data</span><span class="plain-syntax">.</span><span class="element-syntax">nlv_name_translated</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">StandardProblems::sentence_problem</span><span class="plain-syntax">(</span><span class="identifier-syntax">Task::syntax_tree</span><span class="plain-syntax">(),</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">_p_</span><span class="plain-syntax">(</span><span class="identifier-syntax">PM_QuantityTranslatedAlready</span><span class="plain-syntax">),</span>
<span class="plain-syntax"> </span><span class="string-syntax">"this variable has already been translated"</span><span class="plain-syntax">,</span>
<span class="plain-syntax"> </span><span class="string-syntax">"so there must be some duplication somewhere."</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">compilation_data</span><span class="plain-syntax">.</span><span class="element-syntax">nlv_name_translated</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">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">Str::eq</span><span class="plain-syntax">(</span><span class="identifier-syntax">name</span><span class="plain-syntax">, </span><span class="identifier-syntax">I</span><span class="string-syntax">"nothing"</span><span class="plain-syntax">)) {</span>
<span class="plain-syntax"> </span><a href="5-vrb.html#SP4" class="function-link"><span class="function-syntax">RTVariables::set_NVE</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">, </span><a href="5-vrb.html#SP3" class="function-link"><span class="function-syntax">RTVariables::nve_from_nothing</span></a><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">inter_name</span><span class="plain-syntax"> *</span><span class="identifier-syntax">as_iname</span><span class="plain-syntax"> = </span><span class="identifier-syntax">HierarchyLocations::find_by_name</span><span class="plain-syntax">(</span><a href="2-emt.html#SP1" class="function-link"><span class="function-syntax">Emit::tree</span></a><span class="plain-syntax">(), </span><span class="identifier-syntax">name</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><a href="5-vrb.html#SP5" class="function-link"><span class="function-syntax">RTVariables::store_in_this_iname</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">, </span><span class="identifier-syntax">as_iname</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax">}</span>
<span class="reserved-syntax">void</span><span class="plain-syntax"> </span><span class="function-syntax">RTVariables::set_NVE_from_existing</span><span class="plain-syntax">(</span><span class="identifier-syntax">nonlocal_variable</span><span class="plain-syntax"> *</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">, </span><span class="identifier-syntax">nonlocal_variable</span><span class="plain-syntax"> *</span><span class="identifier-syntax">other</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">nlv</span><span class="plain-syntax"> == </span><span class="identifier-syntax">NULL</span><span class="plain-syntax">) </span><span class="identifier-syntax">internal_error</span><span class="plain-syntax">(</span><span class="string-syntax">"null nlv"</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">other</span><span class="plain-syntax"> == </span><span class="identifier-syntax">NULL</span><span class="plain-syntax">) </span><span class="identifier-syntax">internal_error</span><span class="plain-syntax">(</span><span class="string-syntax">"null other"</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><a href="5-vrb.html#SP4" class="function-link"><span class="function-syntax">RTVariables::set_NVE</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">, </span><span class="identifier-syntax">other</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">compilation_data</span><span class="plain-syntax">.</span><span class="element-syntax">rvalue_nve</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>Left and right NVEs may differ in the case where an NLV is tied to a shared
variable which lives fleetingly on the M-stack at runtime. The difference is
essentially that a read of a shared variable (the right NVE) will forgive
the situation in which that variable does not exist; a write to it (the
left NVE) will not. See <a href="../BasicInformKit/S-mst.html" class="internal">MStack (in BasicInformKit)</a> for more.
</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">RTVariables::tie_NLV_to_shared_variable</span><span class="plain-syntax">(</span><span class="identifier-syntax">nonlocal_variable</span><span class="plain-syntax"> *</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">, </span><span class="identifier-syntax">shared_variable</span><span class="plain-syntax"> *</span><span class="identifier-syntax">shv</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">nlv</span><span class="plain-syntax"> == </span><span class="identifier-syntax">NULL</span><span class="plain-syntax">) </span><span class="identifier-syntax">internal_error</span><span class="plain-syntax">(</span><span class="string-syntax">"null nlv"</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">SharedVariables::is_actor</span><span class="plain-syntax">(</span><span class="identifier-syntax">shv</span><span class="plain-syntax">)) {</span>
<span class="plain-syntax"> </span><a href="5-vrb.html#SP5" class="function-link"><span class="function-syntax">RTVariables::store_in_this_iname</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">, </span><a href="2-hrr.html#SP11" class="function-link"><span class="function-syntax">Hierarchy::find</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">ACTOR_HL</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">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">compilation_data</span><span class="plain-syntax">.</span><span class="element-syntax">lvalue_nve</span><span class="plain-syntax"> =</span>
<span class="plain-syntax"> </span><a href="5-vrb.html#SP3" class="function-link"><span class="function-syntax">RTVariables::nve_from_mstack</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">SharedVariables::get_owner_iname</span><span class="plain-syntax">(</span><span class="identifier-syntax">shv</span><span class="plain-syntax">),</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">SharedVariables::get_index</span><span class="plain-syntax">(</span><span class="identifier-syntax">shv</span><span class="plain-syntax">), </span><span class="identifier-syntax">FALSE</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">compilation_data</span><span class="plain-syntax">.</span><span class="element-syntax">rvalue_nve</span><span class="plain-syntax"> =</span>
<span class="plain-syntax"> </span><a href="5-vrb.html#SP3" class="function-link"><span class="function-syntax">RTVariables::nve_from_mstack</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">SharedVariables::get_owner_iname</span><span class="plain-syntax">(</span><span class="identifier-syntax">shv</span><span class="plain-syntax">),</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">SharedVariables::get_index</span><span class="plain-syntax">(</span><span class="identifier-syntax">shv</span><span class="plain-syntax">), </span><span class="identifier-syntax">TRUE</span><span class="plain-syntax">);</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>And the following code results from a reference to the NVE.
</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">RTVariables::compile_NVE_as_val</span><span class="plain-syntax">(</span><span class="identifier-syntax">nonlocal_variable</span><span class="plain-syntax"> *</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">, </span><span class="reserved-syntax">nonlocal_variable_emission</span><span class="plain-syntax"> *</span><span class="identifier-syntax">nve</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">nve</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">iname_form</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><a href="2-ec.html#SP8" class="function-link"><span class="function-syntax">EmitCode::val_iname</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">K_value</span><span class="plain-syntax">, </span><span class="identifier-syntax">nve</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">iname_form</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> } </span><span class="reserved-syntax">else</span><span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">nve</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">shv_set_ID</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><a href="2-ec.html#SP14" class="function-link"><span class="function-syntax">EmitCode::inv</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">LOOKUP_BIP</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><a href="2-ec.html#SP3" class="function-link"><span class="function-syntax">EmitCode::down</span></a><span class="plain-syntax">();</span>
<span class="plain-syntax"> </span><a href="2-ec.html#SP8" class="function-link"><span class="function-syntax">EmitCode::val_iname</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">K_value</span><span class="plain-syntax">, </span><a href="2-hrr.html#SP11" class="function-link"><span class="function-syntax">Hierarchy::find</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">MSTACK_HL</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">ex</span><span class="plain-syntax"> = </span><span class="identifier-syntax">MSTVO_HL</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">nve</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">allow_access_even_if_does_not_exist</span><span class="plain-syntax">) </span><span class="identifier-syntax">ex</span><span class="plain-syntax"> = </span><span class="identifier-syntax">MSTVON_HL</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><a href="2-ec.html#SP14" class="function-link"><span class="function-syntax">EmitCode::call</span></a><span class="plain-syntax">(</span><a href="2-hrr.html#SP11" class="function-link"><span class="function-syntax">Hierarchy::find</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">ex</span><span class="plain-syntax">));</span>
<span class="plain-syntax"> </span><a href="2-ec.html#SP3" class="function-link"><span class="function-syntax">EmitCode::down</span></a><span class="plain-syntax">();</span>
<span class="plain-syntax"> </span><a href="2-ec.html#SP8" class="function-link"><span class="function-syntax">EmitCode::val_iname</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">K_value</span><span class="plain-syntax">, </span><span class="identifier-syntax">nve</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">shv_set_ID</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><a href="2-ec.html#SP8" class="function-link"><span class="function-syntax">EmitCode::val_number</span></a><span class="plain-syntax">((</span><span class="identifier-syntax">inter_ti</span><span class="plain-syntax">) </span><span class="identifier-syntax">nve</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">shv_index</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><a href="2-ec.html#SP3" class="function-link"><span class="function-syntax">EmitCode::up</span></a><span class="plain-syntax">();</span>
<span class="plain-syntax"> </span><a href="2-ec.html#SP3" class="function-link"><span class="function-syntax">EmitCode::up</span></a><span class="plain-syntax">();</span>
<span class="plain-syntax"> } </span><span class="reserved-syntax">else</span><span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">nve</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">use_own_iname</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><a href="2-ec.html#SP8" class="function-link"><span class="function-syntax">EmitCode::val_iname</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">K_value</span><span class="plain-syntax">, </span><a href="5-vrb.html#SP11" class="function-link"><span class="function-syntax">RTVariables::iname</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">));</span>
<span class="plain-syntax"> } </span><span class="reserved-syntax">else</span><span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">nve</span><span class="plain-syntax">-&gt;</span><span class="element-syntax">nothing_form</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><a href="2-ec.html#SP8" class="function-link"><span class="function-syntax">EmitCode::val_iname</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">K_value</span><span class="plain-syntax">, </span><a href="2-hrr.html#SP11" class="function-link"><span class="function-syntax">Hierarchy::find</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">NOTHING_HL</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">internal_error</span><span class="plain-syntax">(</span><span class="string-syntax">"improperly formed nve"</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax">}</span>
</pre>
<p class="commentary firstcommentary"><a id="SP9" class="paragraph-anchor"></a><b>&#167;9. Writing without NVEs. </b>NVEs are a very flexible way to describe a storage location, but they do assume
that a write can be performed by a <span class="extract"><span class="extract-syntax">STORE_BIP</span></span> instruction applied to a reference
to that location &mdash; in other words, by some form of assignment like so:
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="plain-syntax"> Something = value;</span>
<span class="plain-syntax"> (Somewhere--&gt;20) = value;</span>
</pre>
<p class="commentary">And here the term on the left is compiled by wrapping the code produced by
<a href="5-vrb.html#SP8" class="internal">RTVariables::compile_NVE_as_val</a> in a <span class="extract"><span class="extract-syntax">REF_IST</span></span> to make a reference.
This is all well and good. But suppose the assignment has to be made by
some function instead?
</p>
<pre class="displayed-code all-displayed-code code-font">
<span class="plain-syntax"> ChangePlayer(value);</span>
<span class="plain-syntax"> ...</span>
<span class="plain-syntax"> ChangePlayer (val) {</span>
<span class="plain-syntax"> ...</span>
<span class="plain-syntax"> player = val;</span>
<span class="plain-syntax"> ...</span>
<span class="plain-syntax"> }</span>
</pre>
<p class="commentary">An NVE cannot express the need to compile an assignment entirely differently.
So for such cases we provide the ability to set an explicit I6 scheme for
writing. In such a schema, <span class="extract"><span class="extract-syntax">*1</span></span> means the variable, <span class="extract"><span class="extract-syntax">*2</span></span> the value; so, for
example, <span class="extract"><span class="extract-syntax">ChangePlayer(*2)</span></span> could be used in the above example.
</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">RTVariables::set_write_schema</span><button class="popup" onclick="togglePopup('usagePopup8')"><span class="comment-syntax">?</span><span class="popuptext" id="usagePopup8">Usage of <span class="code-font"><span class="function-syntax">RTVariables::set_write_schema</span></span>:<br/>The Player - <a href="6-tp.html#SP2">&#167;2</a></span></button><span class="plain-syntax">(</span><span class="identifier-syntax">nonlocal_variable</span><span class="plain-syntax"> *</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">, </span><span class="identifier-syntax">text_stream</span><span class="plain-syntax"> *</span><span class="identifier-syntax">sch</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">compilation_data</span><span class="plain-syntax">.</span><span class="element-syntax">nlv_write_schema</span><span class="plain-syntax"> = </span><span class="identifier-syntax">Str::duplicate</span><span class="plain-syntax">(</span><span class="identifier-syntax">sch</span><span class="plain-syntax">);</span>
<span class="plain-syntax">}</span>
<span class="identifier-syntax">text_stream</span><span class="plain-syntax"> *</span><span class="function-syntax">RTVariables::get_write_schema</span><span class="plain-syntax">(</span><span class="identifier-syntax">nonlocal_variable</span><span class="plain-syntax"> *</span><span class="identifier-syntax">nlv</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">nlv</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"> </span><span class="identifier-syntax">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">compilation_data</span><span class="plain-syntax">.</span><span class="element-syntax">nlv_write_schema</span><span class="plain-syntax">;</span>
<span class="plain-syntax">}</span>
</pre>
<p class="commentary firstcommentary"><a id="SP10" class="paragraph-anchor"></a><b>&#167;10. Compilation data. </b>Each <span class="extract"><span class="extract-syntax">nonlocal_variable</span></span> object contains this data.
</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">variable_compilation_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">package_request</span><span class="plain-syntax"> *</span><span class="identifier-syntax">nlv_package</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">inter_name</span><span class="plain-syntax"> *</span><span class="identifier-syntax">nlv_iname</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">hierarchy_location_id</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">nlv_name_translated</span><span class="plain-syntax">; </span><span class="comment-syntax"> has this been given storage as an I6 variable?</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">struct</span><span class="plain-syntax"> </span><span class="reserved-syntax">nonlocal_variable_emission</span><span class="plain-syntax"> </span><span class="identifier-syntax">rvalue_nve</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">nonlocal_variable_emission</span><span class="plain-syntax"> </span><span class="identifier-syntax">lvalue_nve</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">text_stream</span><span class="plain-syntax"> *</span><span class="identifier-syntax">nlv_write_schema</span><span class="plain-syntax">; </span><span class="comment-syntax"> </span><span class="extract"><span class="extract-syntax">NULL</span></span><span class="comment-syntax"> for almost all variables</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">int</span><span class="plain-syntax"> </span><span class="identifier-syntax">var_is_initialisable_anyway</span><span class="plain-syntax">; </span><span class="comment-syntax"> meaningful only if not stored in own iname</span>
<span class="plain-syntax">} </span><span class="reserved-syntax">variable_compilation_data</span><span class="plain-syntax">;</span>
<span class="reserved-syntax">variable_compilation_data</span><span class="plain-syntax"> </span><span class="function-syntax">RTVariables::new_compilation_data</span><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">variable_compilation_data</span><span class="plain-syntax"> </span><span class="identifier-syntax">data</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">data</span><span class="plain-syntax">.</span><span class="element-syntax">nlv_package</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">data</span><span class="plain-syntax">.</span><span class="element-syntax">hierarchy_location_id</span><span class="plain-syntax"> = -1;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">data</span><span class="plain-syntax">.</span><span class="element-syntax">nlv_iname</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">data</span><span class="plain-syntax">.</span><span class="element-syntax">nlv_name_translated</span><span class="plain-syntax"> = </span><span class="identifier-syntax">FALSE</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">data</span><span class="plain-syntax">.</span><span class="element-syntax">rvalue_nve</span><span class="plain-syntax"> = </span><a href="5-vrb.html#SP3" class="function-link"><span class="function-syntax">RTVariables::nve_from_own_iname</span></a><span class="plain-syntax">();</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">data</span><span class="plain-syntax">.</span><span class="element-syntax">lvalue_nve</span><span class="plain-syntax"> = </span><a href="5-vrb.html#SP3" class="function-link"><span class="function-syntax">RTVariables::nve_from_own_iname</span></a><span class="plain-syntax">();</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">data</span><span class="plain-syntax">.</span><span class="element-syntax">nlv_write_schema</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">data</span><span class="plain-syntax">.</span><span class="element-syntax">var_is_initialisable_anyway</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">data</span><span class="plain-syntax">;</span>
<span class="plain-syntax">}</span>
</pre>
<ul class="endnotetexts"><li>The structure variable_compilation_data is private to this section.</li></ul>
<p class="commentary firstcommentary"><a id="SP11" class="paragraph-anchor"></a><b>&#167;11. </b>This function should be used immediately after a variable is created, or
</p>
<ul class="items"><li>(preferably) not at all.
</li></ul>
<pre class="displayed-code all-displayed-code code-font">
<span class="reserved-syntax">void</span><span class="plain-syntax"> </span><span class="function-syntax">RTVariables::set_hierarchy_location</span><span class="plain-syntax">(</span><span class="identifier-syntax">nonlocal_variable</span><span class="plain-syntax"> *</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">, </span><span class="reserved-syntax">int</span><span class="plain-syntax"> </span><span class="identifier-syntax">hl</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">compilation_data</span><span class="plain-syntax">.</span><span class="element-syntax">hierarchy_location_id</span><span class="plain-syntax"> = </span><span class="identifier-syntax">hl</span><span class="plain-syntax">;</span>
<span class="plain-syntax">}</span>
<span class="identifier-syntax">package_request</span><span class="plain-syntax"> *</span><span class="function-syntax">RTVariables::package</span><button class="popup" onclick="togglePopup('usagePopup9')"><span class="comment-syntax">?</span><span class="popuptext" id="usagePopup9">Usage of <span class="code-font"><span class="function-syntax">RTVariables::package</span></span>:<br/><a href="5-vrb.html#SP14">&#167;14</a></span></button><span class="plain-syntax">(</span><span class="identifier-syntax">nonlocal_variable</span><span class="plain-syntax"> *</span><span class="identifier-syntax">nlv</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">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">compilation_data</span><span class="plain-syntax">.</span><span class="element-syntax">nlv_package</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">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">compilation_data</span><span class="plain-syntax">.</span><span class="element-syntax">nlv_package</span><span class="plain-syntax"> =</span>
<span class="plain-syntax"> </span><a href="2-hrr.html#SP19" class="function-link"><span class="function-syntax">Hierarchy::local_package_to</span></a><span class="plain-syntax">(</span><span class="constant-syntax">VARIABLES_HAP</span><span class="plain-syntax">,</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">nlv_created_at</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">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">compilation_data</span><span class="plain-syntax">.</span><span class="element-syntax">nlv_package</span><span class="plain-syntax">;</span>
<span class="plain-syntax">}</span>
<span class="identifier-syntax">inter_name</span><span class="plain-syntax"> *</span><span class="function-syntax">RTVariables::iname</span><button class="popup" onclick="togglePopup('usagePopup10')"><span class="comment-syntax">?</span><span class="popuptext" id="usagePopup10">Usage of <span class="code-font"><span class="function-syntax">RTVariables::iname</span></span>:<br/><a href="5-vrb.html#SP8">&#167;8</a>, <a href="5-vrb.html#SP14">&#167;14</a>, <a href="5-vrb.html#SP14_1">&#167;14.1</a></span></button><span class="plain-syntax">(</span><span class="identifier-syntax">nonlocal_variable</span><span class="plain-syntax"> *</span><span class="identifier-syntax">nlv</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">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">compilation_data</span><span class="plain-syntax">.</span><span class="element-syntax">nlv_iname</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">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">compilation_data</span><span class="plain-syntax">.</span><span class="element-syntax">hierarchy_location_id</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">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">compilation_data</span><span class="plain-syntax">.</span><span class="element-syntax">nlv_iname</span><span class="plain-syntax"> =</span>
<span class="plain-syntax"> </span><a href="2-hrr.html#SP11" class="function-link"><span class="function-syntax">Hierarchy::find</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">compilation_data</span><span class="plain-syntax">.</span><span class="element-syntax">hierarchy_location_id</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">else</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">compilation_data</span><span class="plain-syntax">.</span><span class="element-syntax">nlv_iname</span><span class="plain-syntax"> =</span>
<span class="plain-syntax"> </span><a href="2-hrr.html#SP13" class="function-link"><span class="function-syntax">Hierarchy::make_iname_with_memo</span></a><span class="plain-syntax">(</span><span class="constant-syntax">VARIABLE_HL</span><span class="plain-syntax">,</span>
<span class="plain-syntax"> </span><a href="5-vrb.html#SP11" class="function-link"><span class="function-syntax">RTVariables::package</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">), </span><span class="identifier-syntax">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">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">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">compilation_data</span><span class="plain-syntax">.</span><span class="element-syntax">nlv_iname</span><span class="plain-syntax">;</span>
<span class="plain-syntax">}</span>
</pre>
<p class="commentary firstcommentary"><a id="SP12" class="paragraph-anchor"></a><b>&#167;12. </b>Most variables are stored in the default way, and then they are certainly
initialisable. Those stored in some non-standard way are by default not,
unless a call to the following has been made:
</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">RTVariables::make_initialisable</span><span class="plain-syntax">(</span><span class="identifier-syntax">nonlocal_variable</span><span class="plain-syntax"> *</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">compilation_data</span><span class="plain-syntax">.</span><span class="element-syntax">var_is_initialisable_anyway</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="function-syntax">RTVariables::stored_in_own_iname</span><button class="popup" onclick="togglePopup('usagePopup11')"><span class="comment-syntax">?</span><span class="popuptext" id="usagePopup11">Usage of <span class="code-font"><span class="function-syntax">RTVariables::stored_in_own_iname</span></span>:<br/><a href="5-vrb.html#SP14">&#167;14</a></span></button><span class="plain-syntax">(</span><span class="identifier-syntax">nonlocal_variable</span><span class="plain-syntax"> *</span><span class="identifier-syntax">nlv</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">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">compilation_data</span><span class="plain-syntax">.</span><span class="element-syntax">lvalue_nve</span><span class="plain-syntax">.</span><span class="element-syntax">use_own_iname</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><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">int</span><span class="plain-syntax"> </span><span class="function-syntax">RTVariables::is_initialisable</span><span class="plain-syntax">(</span><span class="identifier-syntax">nonlocal_variable</span><span class="plain-syntax"> *</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><a href="5-vrb.html#SP12" class="function-link"><span class="function-syntax">RTVariables::stored_in_own_iname</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">nlv</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><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">compilation_data</span><span class="plain-syntax">.</span><span class="element-syntax">var_is_initialisable_anyway</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><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>
</pre>
<p class="commentary firstcommentary"><a id="SP13" class="paragraph-anchor"></a><b>&#167;13. Compilation. </b>For the sake of the index, we recognise variables with "K understood" names
and mark them with metadata; this doesn't make them behave any differently in
compiled code, of course.
</p>
<pre class="Preform-displayed-code all-displayed-code code-font">
<span class="Preform-function-syntax">&lt;value-understood-variable-name&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;k-kind&gt;</span><span class="Preform-plain-syntax"> </span><span class="Preform-constant-syntax">understood</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="SP14" class="paragraph-anchor"></a><b>&#167;14. </b></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">RTVariables::compile</span><span class="plain-syntax">(</span><span class="identifier-syntax">inference_subject_family</span><span class="plain-syntax"> *</span><span class="identifier-syntax">f</span><span class="plain-syntax">, </span><span class="reserved-syntax">int</span><span class="plain-syntax"> </span><span class="identifier-syntax">ignored</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">nonlocal_variable</span><span class="plain-syntax"> *</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">LOOP_OVER</span><span class="plain-syntax">(</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">, </span><span class="identifier-syntax">nonlocal_variable</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">package_request</span><span class="plain-syntax"> *</span><span class="identifier-syntax">pack</span><span class="plain-syntax"> = </span><a href="5-vrb.html#SP11" class="function-link"><span class="function-syntax">RTVariables::package</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><a href="2-hrr.html#SP23" class="function-link"><span class="function-syntax">Hierarchy::apply_metadata_from_wording</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">pack</span><span class="plain-syntax">, </span><span class="constant-syntax">VARIABLE_NAME_MD_HL</span><span class="plain-syntax">, </span><span class="identifier-syntax">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">name</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::first_wn</span><span class="plain-syntax">(</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">name</span><span class="plain-syntax">) &gt;= </span><span class="constant-syntax">0</span><span class="plain-syntax">) &amp;&amp; (</span><span class="identifier-syntax">NonlocalVariables::is_global</span><span class="plain-syntax">(</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">))) {</span>
<span class="plain-syntax"> </span><a href="2-hrr.html#SP23" class="function-link"><span class="function-syntax">Hierarchy::apply_metadata_from_number</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">pack</span><span class="plain-syntax">, </span><span class="constant-syntax">VARIABLE_AT_MD_HL</span><span class="plain-syntax">,</span>
<span class="plain-syntax"> (</span><span class="identifier-syntax">inter_ti</span><span class="plain-syntax">) </span><span class="identifier-syntax">Wordings::first_wn</span><span class="plain-syntax">(</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">name</span><span class="plain-syntax">));</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">heading</span><span class="plain-syntax"> *</span><span class="identifier-syntax">h</span><span class="plain-syntax"> = </span><span class="identifier-syntax">Headings::of_wording</span><span class="plain-syntax">(</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">name</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><a href="3-cm.html#SP1_13" class="function-link"><span class="function-syntax">CompletionModule::has_heading_id</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">h</span><span class="plain-syntax">))</span>
<span class="plain-syntax"> </span><a href="2-hrr.html#SP23" class="function-link"><span class="function-syntax">Hierarchy::apply_metadata_from_heading</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">pack</span><span class="plain-syntax">, </span><span class="constant-syntax">VARIABLE_HEADING_MD_HL</span><span class="plain-syntax">, </span><span class="identifier-syntax">h</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><a href="2-hrr.html#SP23" class="function-link"><span class="function-syntax">Hierarchy::apply_metadata_from_number</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">pack</span><span class="plain-syntax">, </span><span class="constant-syntax">VARIABLE_INDEXABLE_MD_HL</span><span class="plain-syntax">,</span>
<span class="plain-syntax"> ((</span><span class="identifier-syntax">h</span><span class="plain-syntax">) &amp;&amp; (</span><span class="identifier-syntax">h</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">index_definitions_made_under_this</span><span class="plain-syntax">))?1:0);</span>
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="function-syntax">&lt;value-understood-variable-name&gt;(nlv-&gt;</span><span class="identifier-syntax">name</span><span class="plain-syntax">))</span>
<span class="plain-syntax"> </span><a href="2-hrr.html#SP23" class="function-link"><span class="function-syntax">Hierarchy::apply_metadata_from_number</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">pack</span><span class="plain-syntax">, </span><span class="constant-syntax">VARIABLE_UNDERSTOOD_MD_HL</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::nonempty</span><span class="plain-syntax">(</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">var_documentation_symbol</span><span class="plain-syntax">))</span>
<span class="plain-syntax"> </span><a href="2-hrr.html#SP23" class="function-link"><span class="function-syntax">Hierarchy::apply_metadata_from_raw_wording</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">pack</span><span class="plain-syntax">, </span><span class="constant-syntax">VARIABLE_DOCUMENTATION_MD_HL</span><span class="plain-syntax">,</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">Wordings::one_word</span><span class="plain-syntax">(</span><span class="identifier-syntax">Wordings::first_wn</span><span class="plain-syntax">(</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">var_documentation_symbol</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">contents</span><span class="plain-syntax">)</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">Kinds::Textual::write</span><span class="plain-syntax">(</span><span class="identifier-syntax">contents</span><span class="plain-syntax">, </span><span class="identifier-syntax">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">nlv_kind</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><a href="2-hrr.html#SP23" class="function-link"><span class="function-syntax">Hierarchy::apply_metadata</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">pack</span><span class="plain-syntax">, </span><span class="constant-syntax">VARIABLE_CONTENTS_MD_HL</span><span class="plain-syntax">, </span><span class="identifier-syntax">contents</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">contents</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><a href="5-vrb.html#SP12" class="function-link"><span class="function-syntax">RTVariables::stored_in_own_iname</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">)) ||</span>
<span class="plain-syntax"> (</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">constant_at_run_time</span><span class="plain-syntax"> == </span><span class="identifier-syntax">FALSE</span><span class="plain-syntax">)) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">inter_name</span><span class="plain-syntax"> *</span><span class="identifier-syntax">iname</span><span class="plain-syntax"> = </span><a href="5-vrb.html#SP11" class="function-link"><span class="function-syntax">RTVariables::iname</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">nlv</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">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">compilation_data</span><span class="plain-syntax">.</span><span class="element-syntax">nlv_name_translated</span><span class="plain-syntax"> == </span><span class="identifier-syntax">FALSE</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">inter_pair</span><span class="plain-syntax"> </span><span class="identifier-syntax">val</span><span class="plain-syntax"> = </span><a href="5-vrb.html#SP15" class="function-link"><span class="function-syntax">RTVariables::initial_value_as_pair</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">iname</span><span class="plain-syntax">, </span><span class="identifier-syntax">nlv</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><a href="2-emt.html#SP13" class="function-link"><span class="function-syntax">Emit::variable</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">iname</span><span class="plain-syntax">, </span><span class="identifier-syntax">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">nlv_kind</span><span class="plain-syntax">, </span><span class="identifier-syntax">val</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="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">compilation_data</span><span class="plain-syntax">.</span><span class="element-syntax">lvalue_nve</span><span class="plain-syntax">.</span><span class="element-syntax">iname_form</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">inter_symbol</span><span class="plain-syntax"> *</span><span class="identifier-syntax">S</span><span class="plain-syntax"> = </span><span class="identifier-syntax">InterNames::to_symbol</span><span class="plain-syntax">(</span><span class="identifier-syntax">iname</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">inter_symbol</span><span class="plain-syntax"> *</span><span class="identifier-syntax">H</span><span class="plain-syntax"> = </span><span class="identifier-syntax">InterNames::to_symbol</span><span class="plain-syntax">(</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">compilation_data</span><span class="plain-syntax">.</span><span class="element-syntax">lvalue_nve</span><span class="plain-syntax">.</span><span class="element-syntax">iname_form</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">Wiring::wire_to</span><span class="plain-syntax">(</span><span class="identifier-syntax">S</span><span class="plain-syntax">, </span><span class="identifier-syntax">H</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><a href="2-hrr.html#SP23" class="function-link"><span class="function-syntax">Hierarchy::apply_metadata_from_iname</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">pack</span><span class="plain-syntax">, </span><span class="constant-syntax">VARIABLE_COUNTERPART_MD_HL</span><span class="plain-syntax">,</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">compilation_data</span><span class="plain-syntax">.</span><span class="element-syntax">lvalue_nve</span><span class="plain-syntax">.</span><span class="element-syntax">iname_form</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> </span><span class="named-paragraph-container code-font"><a href="5-vrb.html#SP14_1" class="named-paragraph-link"><span class="named-paragraph">Add any anomalous extras</span><span class="named-paragraph-number">14.1</span></a></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">nlv</span><span class="plain-syntax"> == </span><span class="identifier-syntax">max_score_VAR</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">inter_name</span><span class="plain-syntax"> *</span><span class="identifier-syntax">iname</span><span class="plain-syntax"> = </span><a href="2-hrr.html#SP12" class="function-link"><span class="function-syntax">Hierarchy::make_iname_in</span></a><span class="plain-syntax">(</span><span class="constant-syntax">INITIAL_MAX_SCORE_HL</span><span class="plain-syntax">, </span><span class="identifier-syntax">pack</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><a href="2-hrr.html#SP17" class="function-link"><span class="function-syntax">Hierarchy::make_available</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">iname</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">VariableSubjects::has_initial_value_set</span><span class="plain-syntax">(</span><span class="identifier-syntax">max_score_VAR</span><span class="plain-syntax">)) {</span>
<span class="plain-syntax"> </span><a href="2-emt.html#SP10" class="function-link"><span class="function-syntax">Emit::initial_value_as_constant</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">iname</span><span class="plain-syntax">, </span><span class="identifier-syntax">max_score_VAR</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><a href="2-emt.html#SP6" class="function-link"><span class="function-syntax">Emit::numeric_constant</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">iname</span><span class="plain-syntax">, </span><span class="constant-syntax">0</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> }</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">TRUE</span><span class="plain-syntax">;</span>
<span class="plain-syntax">}</span>
</pre>
<p class="commentary firstcommentary"><a id="SP14_1" class="paragraph-anchor"></a><b>&#167;14.1. </b>Here, an Inter function is compiled which returns the current value of the
command prompt variable; see <a href="../CommandParserKit/S-prs.html" class="internal">Parser (in CommandParserKit)</a>.
</p>
<p class="commentary"><span class="named-paragraph-container code-font"><span class="named-paragraph-defn">Add any anomalous extras</span><span class="named-paragraph-number">14.1</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">nlv</span><span class="plain-syntax"> == </span><span class="identifier-syntax">NonlocalVariables::command_prompt_variable</span><span class="plain-syntax">()) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">inter_name</span><span class="plain-syntax"> *</span><span class="identifier-syntax">iname</span><span class="plain-syntax"> = </span><a href="5-vrb.html#SP11" class="function-link"><span class="function-syntax">RTVariables::iname</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">inter_name</span><span class="plain-syntax"> *</span><span class="identifier-syntax">cpt_iname</span><span class="plain-syntax"> =</span>
<span class="plain-syntax"> </span><a href="2-hrr.html#SP12" class="function-link"><span class="function-syntax">Hierarchy::make_iname_in</span></a><span class="plain-syntax">(</span><span class="constant-syntax">COMMANDPROMPTTEXT_HL</span><span class="plain-syntax">, </span><span class="identifier-syntax">InterNames::location</span><span class="plain-syntax">(</span><span class="identifier-syntax">iname</span><span class="plain-syntax">));</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">packaging_state</span><span class="plain-syntax"> </span><span class="identifier-syntax">save</span><span class="plain-syntax"> = </span><span class="identifier-syntax">Functions::begin</span><span class="plain-syntax">(</span><span class="identifier-syntax">cpt_iname</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><a href="2-ec.html#SP14" class="function-link"><span class="function-syntax">EmitCode::inv</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">RETURN_BIP</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><a href="2-ec.html#SP3" class="function-link"><span class="function-syntax">EmitCode::down</span></a><span class="plain-syntax">();</span>
<span class="plain-syntax"> </span><a href="2-ec.html#SP8" class="function-link"><span class="function-syntax">EmitCode::val_iname</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">K_text</span><span class="plain-syntax">, </span><span class="identifier-syntax">iname</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><a href="2-ec.html#SP3" class="function-link"><span class="function-syntax">EmitCode::up</span></a><span class="plain-syntax">();</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">Functions::end</span><span class="plain-syntax">(</span><span class="identifier-syntax">save</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><a href="2-hrr.html#SP17" class="function-link"><span class="function-syntax">Hierarchy::make_available</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">cpt_iname</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> }</span>
</pre>
<ul class="endnotetexts"><li>This code is used in <a href="5-vrb.html#SP14">&#167;14</a>.</li></ul>
<p class="commentary firstcommentary"><a id="SP15" class="paragraph-anchor"></a><b>&#167;15. Initial values. </b>Three functions which all compile the initial value of a variable, in different
ways:
</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">RTVariables::initial_value_as_array_entry</span><button class="popup" onclick="togglePopup('usagePopup12')"><span class="comment-syntax">?</span><span class="popuptext" id="usagePopup12">Usage of <span class="code-font"><span class="function-syntax">RTVariables::initial_value_as_array_entry</span></span>:<br/>The Player - <a href="6-tp.html#SP1">&#167;1</a></span></button><span class="plain-syntax">(</span><span class="identifier-syntax">nonlocal_variable</span><span class="plain-syntax"> *</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">value_holster</span><span class="plain-syntax"> </span><span class="identifier-syntax">VH</span><span class="plain-syntax"> = </span><span class="identifier-syntax">Holsters::new</span><span class="plain-syntax">(</span><span class="identifier-syntax">INTER_DATA_VHMODE</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><a href="5-vrb.html#SP16" class="function-link"><span class="function-syntax">RTVariables::holster_initial_value</span></a><span class="plain-syntax">(&amp;</span><span class="identifier-syntax">VH</span><span class="plain-syntax">, </span><span class="identifier-syntax">nlv</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">inter_pair</span><span class="plain-syntax"> </span><span class="identifier-syntax">val</span><span class="plain-syntax"> = </span><span class="identifier-syntax">Holsters::unholster_to_pair</span><span class="plain-syntax">(&amp;</span><span class="identifier-syntax">VH</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><a href="2-ea.html#SP4" class="function-link"><span class="function-syntax">EmitArrays::generic_entry</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">val</span><span class="plain-syntax">);</span>
<span class="plain-syntax">}</span>
<span class="reserved-syntax">void</span><span class="plain-syntax"> </span><span class="function-syntax">RTVariables::initial_value_as_val</span><button class="popup" onclick="togglePopup('usagePopup13')"><span class="comment-syntax">?</span><span class="popuptext" id="usagePopup13">Usage of <span class="code-font"><span class="function-syntax">RTVariables::initial_value_as_val</span></span>:<br/>Shared Variables - <a href="2-sv.html#SP1_1">&#167;1.1</a></span></button><span class="plain-syntax">(</span><span class="identifier-syntax">nonlocal_variable</span><span class="plain-syntax"> *</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">value_holster</span><span class="plain-syntax"> </span><span class="identifier-syntax">VH</span><span class="plain-syntax"> = </span><span class="identifier-syntax">Holsters::new</span><span class="plain-syntax">(</span><span class="identifier-syntax">INTER_VAL_VHMODE</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><a href="5-vrb.html#SP16" class="function-link"><span class="function-syntax">RTVariables::holster_initial_value</span></a><span class="plain-syntax">(&amp;</span><span class="identifier-syntax">VH</span><span class="plain-syntax">, </span><span class="identifier-syntax">nlv</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">Holsters::unholster_to_code_val</span><span class="plain-syntax">(</span><a href="2-emt.html#SP1" class="function-link"><span class="function-syntax">Emit::tree</span></a><span class="plain-syntax">(), &amp;</span><span class="identifier-syntax">VH</span><span class="plain-syntax">);</span>
<span class="plain-syntax">}</span>
<span class="identifier-syntax">inter_pair</span><span class="plain-syntax"> </span><span class="function-syntax">RTVariables::initial_value_as_pair</span><button class="popup" onclick="togglePopup('usagePopup14')"><span class="comment-syntax">?</span><span class="popuptext" id="usagePopup14">Usage of <span class="code-font"><span class="function-syntax">RTVariables::initial_value_as_pair</span></span>:<br/><a href="5-vrb.html#SP14">&#167;14</a><br/>Emit - <a href="2-emt.html#SP10">&#167;10</a></span></button><span class="plain-syntax">(</span><span class="identifier-syntax">inter_name</span><span class="plain-syntax"> *</span><span class="identifier-syntax">iname</span><span class="plain-syntax">, </span><span class="identifier-syntax">nonlocal_variable</span><span class="plain-syntax"> *</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">value_holster</span><span class="plain-syntax"> </span><span class="identifier-syntax">VH</span><span class="plain-syntax"> = </span><span class="identifier-syntax">Holsters::new</span><span class="plain-syntax">(</span><span class="identifier-syntax">INTER_DATA_VHMODE</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">packaging_state</span><span class="plain-syntax"> </span><span class="identifier-syntax">save</span><span class="plain-syntax"> = </span><span class="identifier-syntax">Packaging::enter_home_of</span><span class="plain-syntax">(</span><span class="identifier-syntax">iname</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><a href="5-vrb.html#SP16" class="function-link"><span class="function-syntax">RTVariables::holster_initial_value</span></a><span class="plain-syntax">(&amp;</span><span class="identifier-syntax">VH</span><span class="plain-syntax">, </span><span class="identifier-syntax">nlv</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">inter_pair</span><span class="plain-syntax"> </span><span class="identifier-syntax">val</span><span class="plain-syntax"> = </span><span class="identifier-syntax">Holsters::unholster_to_pair</span><span class="plain-syntax">(&amp;</span><span class="identifier-syntax">VH</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">Packaging::exit</span><span class="plain-syntax">(</span><a href="2-emt.html#SP1" class="function-link"><span class="function-syntax">Emit::tree</span></a><span class="plain-syntax">(), </span><span class="identifier-syntax">save</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">val</span><span class="plain-syntax">;</span>
<span class="plain-syntax">}</span>
</pre>
<p class="commentary firstcommentary"><a id="SP16" class="paragraph-anchor"></a><b>&#167;16. </b>Which are all powered by the following function.
</p>
<p class="commentary">If the variable has no known initial value, it is given the initial
value for its kind where possible: but note that this may not be possible
if the source text says something like
</p>
<blockquote>
<p>Thickness is a kind of value. The carpet nap is a thickness that varies.</p>
</blockquote>
<p class="commentary">without specifying any thicknesses. If that's so, the set of legal thickness
values is empty, so the "carpet nap" variable cannot be created in a way
which makes its kind safe.
</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">RTVariables::holster_initial_value</span><button class="popup" onclick="togglePopup('usagePopup15')"><span class="comment-syntax">?</span><span class="popuptext" id="usagePopup15">Usage of <span class="code-font"><span class="function-syntax">RTVariables::holster_initial_value</span></span>:<br/><a href="5-vrb.html#SP15">&#167;15</a></span></button><span class="plain-syntax">(</span><span class="identifier-syntax">value_holster</span><span class="plain-syntax"> *</span><span class="identifier-syntax">VH</span><span class="plain-syntax">, </span><span class="identifier-syntax">nonlocal_variable</span><span class="plain-syntax"> *</span><span class="identifier-syntax">nlv</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">val</span><span class="plain-syntax"> =</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">NonlocalVariables::substitute_constants</span><span class="plain-syntax">(</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">VariableSubjects::get_initial_value</span><span class="plain-syntax">(</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">nlv</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">val</span><span class="plain-syntax">, </span><span class="identifier-syntax">UNKNOWN_NT</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">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">nlv_created_at</span><span class="plain-syntax">;</span>
<span class="plain-syntax"> </span><span class="named-paragraph-container code-font"><a href="5-vrb.html#SP16_1" class="named-paragraph-link"><span class="named-paragraph">Initialise with the default value of its kind</span><span class="named-paragraph-number">16.1</span></a></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">current_sentence</span><span class="plain-syntax"> = </span><span class="identifier-syntax">VariableSubjects::origin_of_initial_value</span><span class="plain-syntax">(</span><span class="identifier-syntax">nlv</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::get_storage_form</span><span class="plain-syntax">(</span><span class="identifier-syntax">val</span><span class="plain-syntax">) == </span><span class="identifier-syntax">NONLOCAL_VARIABLE_NT</span><span class="plain-syntax">)</span>
<span class="plain-syntax"> </span><span class="named-paragraph-container code-font"><a href="5-vrb.html#SP16_2" class="named-paragraph-link"><span class="named-paragraph">Issue a problem for one variable set equal to another</span><span class="named-paragraph-number">16.2</span></a></span>
<span class="plain-syntax"> </span><span class="reserved-syntax">else</span><span class="plain-syntax"> </span><span class="identifier-syntax">CompileValues::constant_to_holster</span><span class="plain-syntax">(</span><span class="identifier-syntax">VH</span><span class="plain-syntax">, </span><span class="identifier-syntax">val</span><span class="plain-syntax">, </span><span class="identifier-syntax">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">nlv_kind</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax">}</span>
</pre>
<p class="commentary firstcommentary"><a id="SP16_1" class="paragraph-anchor"></a><b>&#167;16.1. </b><span class="named-paragraph-container code-font"><span class="named-paragraph-defn">Initialise with the default value of its kind</span><span class="named-paragraph-number">16.1</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><a href="2-dv.html#SP1" class="function-link"><span class="function-syntax">DefaultValues::to_holster</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">VH</span><span class="plain-syntax">, </span><span class="identifier-syntax">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">nlv_kind</span><span class="plain-syntax">, </span><span class="identifier-syntax">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">name</span><span class="plain-syntax">, </span><span class="string-syntax">"variable"</span><span class="plain-syntax">, </span><span class="identifier-syntax">FALSE</span><span class="plain-syntax">)</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">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">var_is_allowed_to_be_zero</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">Holsters::holster_pair</span><span class="plain-syntax">(</span><span class="identifier-syntax">VH</span><span class="plain-syntax">, </span><span class="identifier-syntax">InterValuePairs::number</span><span class="plain-syntax">(0));</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">wording</span><span class="plain-syntax"> </span><span class="identifier-syntax">W</span><span class="plain-syntax"> = </span><span class="identifier-syntax">Kinds::Behaviour::get_name</span><span class="plain-syntax">(</span><span class="identifier-syntax">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">nlv_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="identifier-syntax">Problems::quote_wording</span><span class="plain-syntax">(1, </span><span class="identifier-syntax">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">name</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">Problems::quote_wording</span><span class="plain-syntax">(2, </span><span class="identifier-syntax">W</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">StandardProblems::handmade_problem</span><span class="plain-syntax">(</span><span class="identifier-syntax">Task::syntax_tree</span><span class="plain-syntax">(), </span><span class="identifier-syntax">_p_</span><span class="plain-syntax">(</span><span class="identifier-syntax">PM_EmptyDataType</span><span class="plain-syntax">));</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">Problems::issue_problem_segment</span><span class="plain-syntax">(</span>
<span class="plain-syntax"> </span><span class="string-syntax">"I am unable to put any value into the variable '%1', because "</span>
<span class="plain-syntax"> </span><span class="string-syntax">"%2 is a kind of value with no actual values."</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">Problems::issue_problem_end</span><span class="plain-syntax">();</span>
<span class="plain-syntax"> }</span>
<span class="plain-syntax"> }</span>
</pre>
<ul class="endnotetexts"><li>This code is used in <a href="5-vrb.html#SP16">&#167;16</a>.</li></ul>
<p class="commentary firstcommentary"><a id="SP16_2" class="paragraph-anchor"></a><b>&#167;16.2. </b><span class="named-paragraph-container code-font"><span class="named-paragraph-defn">Issue a problem for one variable set equal to another</span><span class="named-paragraph-number">16.2</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">nonlocal_variable</span><span class="plain-syntax"> *</span><span class="identifier-syntax">the_other</span><span class="plain-syntax"> = </span><span class="identifier-syntax">Node::get_constant_nonlocal_variable</span><span class="plain-syntax">(</span><span class="identifier-syntax">val</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">the_other</span><span class="plain-syntax"> == </span><span class="identifier-syntax">NULL</span><span class="plain-syntax">) </span><span class="identifier-syntax">internal_error</span><span class="plain-syntax">(</span>
<span class="plain-syntax"> </span><span class="string-syntax">"Tried to compile initial value of variable as null variable"</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">the_other</span><span class="plain-syntax"> == </span><span class="identifier-syntax">nlv</span><span class="plain-syntax">) {</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">Problems::quote_source</span><span class="plain-syntax">(1, </span><span class="identifier-syntax">current_sentence</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">Problems::quote_wording</span><span class="plain-syntax">(2, </span><span class="identifier-syntax">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">name</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">Problems::quote_kind</span><span class="plain-syntax">(3, </span><span class="identifier-syntax">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">nlv_kind</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">StandardProblems::handmade_problem</span><span class="plain-syntax">(</span><span class="identifier-syntax">Task::syntax_tree</span><span class="plain-syntax">(), </span><span class="identifier-syntax">_p_</span><span class="plain-syntax">(</span><span class="identifier-syntax">PM_InitialiseQ2</span><span class="plain-syntax">));</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">Problems::issue_problem_segment</span><span class="plain-syntax">(</span>
<span class="plain-syntax"> </span><span class="string-syntax">"The sentence %1 tells me that '%2', which should be %3 "</span>
<span class="plain-syntax"> </span><span class="string-syntax">"that varies, is to have an initial value equal to itself - "</span>
<span class="plain-syntax"> </span><span class="string-syntax">"this is such an odd thing to say that I think I must have "</span>
<span class="plain-syntax"> </span><span class="string-syntax">"misunderstood."</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">Problems::issue_problem_end</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">Problems::quote_source</span><span class="plain-syntax">(1, </span><span class="identifier-syntax">current_sentence</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">Problems::quote_wording</span><span class="plain-syntax">(2, </span><span class="identifier-syntax">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">name</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">Problems::quote_kind</span><span class="plain-syntax">(3, </span><span class="identifier-syntax">nlv</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">nlv_kind</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">Problems::quote_wording</span><span class="plain-syntax">(4, </span><span class="identifier-syntax">the_other</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">name</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">Problems::quote_kind</span><span class="plain-syntax">(5, </span><span class="identifier-syntax">the_other</span><span class="plain-syntax">-&gt;</span><span class="identifier-syntax">nlv_kind</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">StandardProblems::handmade_problem</span><span class="plain-syntax">(</span><span class="identifier-syntax">Task::syntax_tree</span><span class="plain-syntax">(), </span><span class="identifier-syntax">_p_</span><span class="plain-syntax">(</span><span class="identifier-syntax">PM_InitialiseQ1</span><span class="plain-syntax">));</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">Problems::issue_problem_segment</span><span class="plain-syntax">(</span>
<span class="plain-syntax"> </span><span class="string-syntax">"The sentence %1 tells me that '%2', which should be %3 "</span>
<span class="plain-syntax"> </span><span class="string-syntax">"that varies, is to have an initial value equal to '%4', "</span>
<span class="plain-syntax"> </span><span class="string-syntax">"which in turn is %5 that varies. At the start of play, "</span>
<span class="plain-syntax"> </span><span class="string-syntax">"variable values have to be set equal to definite constants, "</span>
<span class="plain-syntax"> </span><span class="string-syntax">"so this is not allowed."</span><span class="plain-syntax">);</span>
<span class="plain-syntax"> </span><span class="identifier-syntax">Problems::issue_problem_end</span><span class="plain-syntax">();</span>
<span class="plain-syntax"> }</span>
</pre>
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