mirror of
https://github.com/ganelson/inform.git
synced 2024-07-08 01:54:21 +03:00
311 lines
41 KiB
HTML
311 lines
41 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
|
<html>
|
|
<head>
|
|
<title>Compile Conditions</title>
|
|
<link href="../docs-assets/Breadcrumbs.css" rel="stylesheet" rev="stylesheet" type="text/css">
|
|
<meta name="viewport" content="width=device-width initial-scale=1">
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
|
|
<meta http-equiv="Content-Language" content="en-gb">
|
|
|
|
<link href="../docs-assets/Contents.css" rel="stylesheet" rev="stylesheet" type="text/css">
|
|
<link href="../docs-assets/Progress.css" rel="stylesheet" rev="stylesheet" type="text/css">
|
|
<link href="../docs-assets/Navigation.css" rel="stylesheet" rev="stylesheet" type="text/css">
|
|
<link href="../docs-assets/Fonts.css" rel="stylesheet" rev="stylesheet" type="text/css">
|
|
<link href="../docs-assets/Base.css" rel="stylesheet" rev="stylesheet" type="text/css">
|
|
<script>
|
|
function togglePopup(material_id) {
|
|
var popup = document.getElementById(material_id);
|
|
popup.classList.toggle("show");
|
|
}
|
|
</script>
|
|
|
|
<link href="../docs-assets/Popups.css" rel="stylesheet" rev="stylesheet" type="text/css">
|
|
<script>
|
|
MathJax = {
|
|
tex: {
|
|
inlineMath: '$', '$'], ['\\(', '\\)'
|
|
},
|
|
svg: {
|
|
fontCache: 'global'
|
|
}
|
|
};
|
|
</script>
|
|
<script type="text/javascript" id="MathJax-script" async
|
|
src="https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-svg.js">
|
|
</script>
|
|
|
|
<link href="../docs-assets/Colours.css" rel="stylesheet" rev="stylesheet" type="text/css">
|
|
|
|
</head>
|
|
<body class="commentary-font">
|
|
<nav role="navigation">
|
|
<h1><a href="../index.html">
|
|
<img src="../docs-assets/Inform.png" height=72">
|
|
</a></h1>
|
|
<ul><li><a href="../compiler.html">compiler tools</a></li>
|
|
<li><a href="../other.html">other tools</a></li>
|
|
<li><a href="../extensions.html">extensions and kits</a></li>
|
|
<li><a href="../units.html">unit test tools</a></li>
|
|
</ul><h2>Compiler Webs</h2><ul>
|
|
<li><a href="../inbuild/index.html">inbuild</a></li>
|
|
<li><a href="../inform7/index.html">inform7</a></li>
|
|
<li><a href="../inter/index.html">inter</a></li>
|
|
</ul><h2>Inbuild Modules</h2><ul>
|
|
<li><a href="../supervisor-module/index.html">supervisor</a></li>
|
|
</ul><h2>Inform7 Modules</h2><ul>
|
|
<li><a href="../core-module/index.html">core</a></li>
|
|
<li><a href="../assertions-module/index.html">assertions</a></li>
|
|
<li><a href="../values-module/index.html">values</a></li>
|
|
<li><a href="../knowledge-module/index.html">knowledge</a></li>
|
|
<li><a href="index.html"><span class="selectedlink">imperative</span></a></li>
|
|
<li><a href="../runtime-module/index.html">runtime</a></li>
|
|
<li><a href="../if-module/index.html">if</a></li>
|
|
<li><a href="../multimedia-module/index.html">multimedia</a></li>
|
|
<li><a href="../index-module/index.html">index</a></li>
|
|
</ul><h2>Inter Modules</h2><ul>
|
|
<li><a href="../bytecode-module/index.html">bytecode</a></li>
|
|
<li><a href="../building-module/index.html">building</a></li>
|
|
<li><a href="../pipeline-module/index.html">pipeline</a></li>
|
|
<li><a href="../final-module/index.html">final</a></li>
|
|
</ul><h2>Services</h2><ul>
|
|
<li><a href="../arch-module/index.html">arch</a></li>
|
|
<li><a href="../calculus-module/index.html">calculus</a></li>
|
|
<li><a href="../html-module/index.html">html</a></li>
|
|
<li><a href="../inflections-module/index.html">inflections</a></li>
|
|
<li><a href="../kinds-module/index.html">kinds</a></li>
|
|
<li><a href="../linguistics-module/index.html">linguistics</a></li>
|
|
<li><a href="../problems-module/index.html">problems</a></li>
|
|
<li><a href="../syntax-module/index.html">syntax</a></li>
|
|
<li><a href="../words-module/index.html">words</a></li>
|
|
<li><a href="../../../inweb/docs/foundation-module/index.html">foundation</a></li>
|
|
|
|
</ul>
|
|
</nav>
|
|
<main role="main">
|
|
<!--Weave of 'Compile Conditions' generated by Inweb-->
|
|
<div class="breadcrumbs">
|
|
<ul class="crumbs"><li><a href="../index.html">Home</a></li><li><a href="../compiler.html">Inform7</a></li><li><a href="index.html">imperative</a></li><li><a href="index.html#2">Chapter 2: Values</a></li><li><b>Compile Conditions</b></li></ul></div>
|
|
<p class="purpose">To compile Inter code to test a condition.</p>
|
|
|
|
<p class="commentary firstcommentary"><a id="SP1" class="paragraph-anchor"></a><b>§1. </b>In fact almost all of the work is delegated to more potent routines elsewhere.
|
|
Much of <a href="4-cs.html" class="internal">Chapter 4: Propositions</a> is really dedicated to this.
|
|
</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">CompileConditions::compile</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">CompileConditions::compile</span></span>:<br/>Compile Values - <a href="2-cv.html#SP6_1_1">§6.1.1</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">parse_node</span><span class="plain-syntax"> *</span><span class="identifier-syntax">cond</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">PluginCalls::compile_condition</span><span class="plain-syntax">(</span><span class="identifier-syntax">VH</span><span class="plain-syntax">, </span><span class="identifier-syntax">cond</span><span class="plain-syntax">)) </span><span class="reserved-syntax">return</span><span class="plain-syntax">;</span>
|
|
<span class="plain-syntax"> </span><span class="reserved-syntax">switch</span><span class="plain-syntax"> (</span><span class="identifier-syntax">Node::get_type</span><span class="plain-syntax">(</span><span class="identifier-syntax">cond</span><span class="plain-syntax">)) {</span>
|
|
<span class="plain-syntax"> </span><span class="reserved-syntax">case</span><span class="plain-syntax"> </span><span class="identifier-syntax">TEST_PROPOSITION_NT:</span>
|
|
<span class="plain-syntax"> </span><a href="4-cp.html#SP1" class="function-link"><span class="function-syntax">CompilePropositions::to_test_as_condition</span></a><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">Specifications::to_proposition</span><span class="plain-syntax">(</span><span class="identifier-syntax">cond</span><span class="plain-syntax">));</span>
|
|
<span class="plain-syntax"> </span><span class="reserved-syntax">break</span><span class="plain-syntax">;</span>
|
|
<span class="plain-syntax"> </span><span class="reserved-syntax">case</span><span class="plain-syntax"> </span><span class="identifier-syntax">LOGICAL_TENSE_NT:</span>
|
|
<span class="plain-syntax"> </span><span class="identifier-syntax">Chronology::compile_past_tense_condition</span><span class="plain-syntax">(</span><span class="identifier-syntax">cond</span><span class="plain-syntax">);</span>
|
|
<span class="plain-syntax"> </span><span class="reserved-syntax">break</span><span class="plain-syntax">;</span>
|
|
<span class="plain-syntax"> </span><span class="reserved-syntax">case</span><span class="plain-syntax"> </span><span class="identifier-syntax">LOGICAL_NOT_NT:</span><span class="plain-syntax"> </span><span class="named-paragraph-container code-font"><a href="2-cc.html#SP1_1" class="named-paragraph-link"><span class="named-paragraph">Compile a logical negation</span><span class="named-paragraph-number">1.1</span></a></span><span class="plain-syntax">; </span><span class="reserved-syntax">break</span><span class="plain-syntax">;</span>
|
|
<span class="plain-syntax"> </span><span class="reserved-syntax">case</span><span class="plain-syntax"> </span><span class="identifier-syntax">LOGICAL_AND_NT:</span><span class="plain-syntax"> </span><span class="reserved-syntax">case</span><span class="plain-syntax"> </span><span class="identifier-syntax">LOGICAL_OR_NT:</span><span class="plain-syntax"> </span><span class="named-paragraph-container code-font"><a href="2-cc.html#SP1_2" class="named-paragraph-link"><span class="named-paragraph">Compile a logical operator</span><span class="named-paragraph-number">1.2</span></a></span><span class="plain-syntax">; </span><span class="reserved-syntax">break</span><span class="plain-syntax">;</span>
|
|
<span class="plain-syntax"> </span><span class="reserved-syntax">case</span><span class="plain-syntax"> </span><span class="identifier-syntax">TEST_VALUE_NT:</span>
|
|
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">Specifications::is_description</span><span class="plain-syntax">(</span><span class="identifier-syntax">cond</span><span class="plain-syntax">)) {</span>
|
|
<span class="plain-syntax"> </span><span class="comment-syntax"> purely for problem recovery:</span>
|
|
<span class="plain-syntax"> </span><span class="identifier-syntax">EmitCode::val_number</span><span class="plain-syntax">(1);</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-cv.html#SP5" class="function-link"><span class="function-syntax">CompileValues::to_code_val</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">cond</span><span class="plain-syntax">-></span><span class="identifier-syntax">down</span><span class="plain-syntax">);</span>
|
|
<span class="plain-syntax"> }</span>
|
|
<span class="plain-syntax"> </span><span class="reserved-syntax">break</span><span class="plain-syntax">;</span>
|
|
<span class="plain-syntax"> </span><span class="reserved-syntax">case</span><span class="plain-syntax"> </span><span class="identifier-syntax">TEST_PHRASE_OPTION_NT:</span><span class="plain-syntax"> </span><span class="named-paragraph-container code-font"><a href="2-cc.html#SP1_3" class="named-paragraph-link"><span class="named-paragraph">Compile a phrase option test</span><span class="named-paragraph-number">1.3</span></a></span><span class="plain-syntax">; </span><span class="reserved-syntax">break</span><span class="plain-syntax">;</span>
|
|
<span class="plain-syntax"> }</span>
|
|
<span class="plain-syntax">}</span>
|
|
</pre>
|
|
<p class="commentary firstcommentary"><a id="SP1_1" class="paragraph-anchor"></a><b>§1.1. </b>An easy case, running straight out to Inter operators:
|
|
</p>
|
|
|
|
<p class="commentary"><span class="named-paragraph-container code-font"><span class="named-paragraph-defn">Compile a logical negation</span><span class="named-paragraph-number">1.1</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">Node::no_children</span><span class="plain-syntax">(</span><span class="identifier-syntax">cond</span><span class="plain-syntax">) != </span><span class="constant-syntax">1</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">"Compiled malformed LOGICAL_NOT_NT"</span><span class="plain-syntax">);</span>
|
|
<span class="plain-syntax"> </span><span class="identifier-syntax">EmitCode::inv</span><span class="plain-syntax">(</span><span class="identifier-syntax">NOT_BIP</span><span class="plain-syntax">);</span>
|
|
<span class="plain-syntax"> </span><span class="identifier-syntax">EmitCode::down</span><span class="plain-syntax">();</span>
|
|
<span class="plain-syntax"> </span><a href="2-cv.html#SP5" class="function-link"><span class="function-syntax">CompileValues::to_code_val</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">cond</span><span class="plain-syntax">-></span><span class="identifier-syntax">down</span><span class="plain-syntax">);</span>
|
|
<span class="plain-syntax"> </span><span class="identifier-syntax">EmitCode::up</span><span class="plain-syntax">();</span>
|
|
</pre>
|
|
<ul class="endnotetexts"><li>This code is used in <a href="2-cc.html#SP1">§1</a>.</li></ul>
|
|
<p class="commentary firstcommentary"><a id="SP1_2" class="paragraph-anchor"></a><b>§1.2. </b>An easy case, running straight out to Inter operators:
|
|
</p>
|
|
|
|
<p class="commentary"><span class="named-paragraph-container code-font"><span class="named-paragraph-defn">Compile a logical operator</span><span class="named-paragraph-number">1.2</span></span><span class="comment-syntax"> =</span>
|
|
</p>
|
|
|
|
<pre class="displayed-code all-displayed-code code-font">
|
|
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">Node::no_children</span><span class="plain-syntax">(</span><span class="identifier-syntax">cond</span><span class="plain-syntax">) != </span><span class="constant-syntax">2</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">"Compiled malformed logical operator"</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">left_operand</span><span class="plain-syntax"> = </span><span class="identifier-syntax">cond</span><span class="plain-syntax">-></span><span class="identifier-syntax">down</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">right_operand</span><span class="plain-syntax"> = </span><span class="identifier-syntax">cond</span><span class="plain-syntax">-></span><span class="identifier-syntax">down</span><span class="plain-syntax">-></span><span class="identifier-syntax">next</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">left_operand</span><span class="plain-syntax"> == </span><span class="identifier-syntax">NULL</span><span class="plain-syntax">) || (</span><span class="identifier-syntax">right_operand</span><span class="plain-syntax"> == </span><span class="identifier-syntax">NULL</span><span class="plain-syntax">))</span>
|
|
<span class="plain-syntax"> </span><span class="identifier-syntax">internal_error</span><span class="plain-syntax">(</span><span class="string-syntax">"Compiled CONDITION/AND with LHS operands"</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">cond</span><span class="plain-syntax">, </span><span class="identifier-syntax">LOGICAL_AND_NT</span><span class="plain-syntax">)) </span><span class="identifier-syntax">EmitCode::inv</span><span class="plain-syntax">(</span><span class="identifier-syntax">AND_BIP</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">cond</span><span class="plain-syntax">, </span><span class="identifier-syntax">LOGICAL_OR_NT</span><span class="plain-syntax">)) </span><span class="identifier-syntax">EmitCode::inv</span><span class="plain-syntax">(</span><span class="identifier-syntax">OR_BIP</span><span class="plain-syntax">);</span>
|
|
<span class="plain-syntax"> </span><span class="identifier-syntax">EmitCode::down</span><span class="plain-syntax">();</span>
|
|
<span class="plain-syntax"> </span><a href="2-cv.html#SP5" class="function-link"><span class="function-syntax">CompileValues::to_code_val</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">left_operand</span><span class="plain-syntax">);</span>
|
|
<span class="plain-syntax"> </span><a href="2-cv.html#SP5" class="function-link"><span class="function-syntax">CompileValues::to_code_val</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">right_operand</span><span class="plain-syntax">);</span>
|
|
<span class="plain-syntax"> </span><span class="identifier-syntax">EmitCode::up</span><span class="plain-syntax">();</span>
|
|
</pre>
|
|
<ul class="endnotetexts"><li>This code is used in <a href="2-cc.html#SP1">§1</a>.</li></ul>
|
|
<p class="commentary firstcommentary"><a id="SP1_3" class="paragraph-anchor"></a><b>§1.3. </b>Phrase options are stored as bits in a 16-bit map, so that each individual
|
|
option is a power of two from \(2^0\) to \(2^15\). We test if this is valid by
|
|
performing logical-and against the Inter local variable <span class="extract"><span class="extract-syntax">phrase_options</span></span>, which
|
|
exists if and only if the enclosing Inter routine takes phrase options. The
|
|
type-checker won't allow these specifications to be compiled anywhere else.
|
|
</p>
|
|
|
|
<p class="commentary"><span class="named-paragraph-container code-font"><span class="named-paragraph-defn">Compile a phrase option test</span><span class="named-paragraph-number">1.3</span></span><span class="comment-syntax"> =</span>
|
|
</p>
|
|
|
|
<pre class="displayed-code all-displayed-code code-font">
|
|
<span class="plain-syntax"> </span><span class="identifier-syntax">EmitCode::inv</span><span class="plain-syntax">(</span><span class="identifier-syntax">BITWISEAND_BIP</span><span class="plain-syntax">);</span>
|
|
<span class="plain-syntax"> </span><span class="identifier-syntax">EmitCode::down</span><span class="plain-syntax">();</span>
|
|
<span class="plain-syntax"> </span><span class="reserved-syntax">local_variable</span><span class="plain-syntax"> *</span><span class="identifier-syntax">po</span><span class="plain-syntax"> = </span><a href="3-lv.html#SP5" class="function-link"><span class="function-syntax">LocalVariables::options_parameter</span></a><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">po</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">"no phrase options exist in this frame"</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">po_s</span><span class="plain-syntax"> = </span><a href="3-lv.html#SP1" class="function-link"><span class="function-syntax">LocalVariables::declare</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">po</span><span class="plain-syntax">);</span>
|
|
<span class="plain-syntax"> </span><span class="identifier-syntax">EmitCode::val_symbol</span><span class="plain-syntax">(</span><span class="identifier-syntax">K_value</span><span class="plain-syntax">, </span><span class="identifier-syntax">po_s</span><span class="plain-syntax">);</span>
|
|
<span class="plain-syntax"> </span><span class="identifier-syntax">EmitCode::val_number</span><span class="plain-syntax">((</span><span class="identifier-syntax">inter_ti</span><span class="plain-syntax">) </span><span class="identifier-syntax">Annotations::read_int</span><span class="plain-syntax">(</span><span class="identifier-syntax">cond</span><span class="plain-syntax">, </span><span class="identifier-syntax">phrase_option_ANNOT</span><span class="plain-syntax">));</span>
|
|
<span class="plain-syntax"> </span><span class="identifier-syntax">EmitCode::up</span><span class="plain-syntax">();</span>
|
|
</pre>
|
|
<ul class="endnotetexts"><li>This code is used in <a href="2-cc.html#SP1">§1</a>.</li></ul>
|
|
<p class="commentary firstcommentary"><a id="SP2" class="paragraph-anchor"></a><b>§2. </b>We need a mechanism for keeping track of the callings made in a condition,
|
|
and here it is. An issue here is that they generally have a scope extending
|
|
beyond that condition, and can't be left with kind-unsafe (or no) values. For
|
|
example, if:
|
|
</p>
|
|
|
|
<blockquote>
|
|
<p>if a device (called the mechanism) is switched on: ...</p>
|
|
</blockquote>
|
|
|
|
<p class="commentary">turns out false, then "mechanism" has to be safely defused to some typesafe value.
|
|
So, then, the model is that if some part of Inform wants to compile a condition
|
|
which may involve callings, it should call <a href="2-cc.html#SP3" class="internal">CompileConditions::begin</a> first,
|
|
then notify us with <a href="2-cc.html#SP4" class="internal">CompileConditions::add_calling</a> of any local being used
|
|
as a calling, and then <a href="2-cc.html#SP5" class="internal">CompileConditions::end</a> when the code is done.
|
|
</p>
|
|
|
|
<p class="commentary">Callings arise from variables in predicate calculus, and there can only be 26
|
|
of those, so the following looks excessive. Well, so it is, of course: Inform
|
|
code in the wild never makes more than about three callings in any one condition.
|
|
But note that these condition sessions can be nested: you can begin a second
|
|
one inside the first, provided that you end it before you end the first one.
|
|
</p>
|
|
|
|
<pre class="definitions code-font"><span class="definition-keyword">define</span> <span class="constant-syntax">MAX_CALLINGS_IN_MATCH</span><span class="plain-syntax"> </span><span class="constant-syntax">128</span>
|
|
</pre>
|
|
<pre class="displayed-code all-displayed-code code-font">
|
|
<span class="reserved-syntax">int</span><span class="plain-syntax"> </span><span class="identifier-syntax">current_session_number</span><span class="plain-syntax"> = -1;</span>
|
|
<span class="reserved-syntax">int</span><span class="plain-syntax"> </span><span class="identifier-syntax">callings_in_condition_sp</span><span class="plain-syntax"> = </span><span class="constant-syntax">0</span><span class="plain-syntax">;</span>
|
|
<span class="reserved-syntax">int</span><span class="plain-syntax"> </span><span class="identifier-syntax">callings_session_number</span><span class="plain-syntax">[</span><span class="constant-syntax">MAX_CALLINGS_IN_MATCH</span><span class="plain-syntax">];</span>
|
|
<span class="reserved-syntax">local_variable</span><span class="plain-syntax"> *</span><span class="identifier-syntax">callings_in_condition</span><span class="plain-syntax">[</span><span class="constant-syntax">MAX_CALLINGS_IN_MATCH</span><span class="plain-syntax">];</span>
|
|
</pre>
|
|
<p class="commentary firstcommentary"><a id="SP3" class="paragraph-anchor"></a><b>§3. </b>The basic strategy here is to compile this:
|
|
</p>
|
|
|
|
<pre class="displayed-code all-displayed-code code-font">
|
|
<span class="plain-syntax"> ((condition setting C1, ..., Ci) || (C1 = default, C2 = default, ..., Ci = default))</span>
|
|
</pre>
|
|
<p class="commentary">using the short-circuit property of <span class="extract"><span class="extract-syntax">OR_BIP</span></span>: if the condition evaluates to false,
|
|
and therefore there is no consistent set of values written into the calling
|
|
variables <span class="extract"><span class="extract-syntax">C1</span></span> to <span class="extract"><span class="extract-syntax">Ci</span></span>, then we evaluate the second clause, and set all of the
|
|
variables to default values for their kinds. In particular, if the condition
|
|
fails halfway, with some callings set and some not, they are all defaulted out,
|
|
so that you can never see partial results.
|
|
</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">CompileConditions::begin</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">CompileConditions::begin</span></span>:<br/>Matching Action Patterns - <a href="2-map.html#SP3_5">§3.5</a><br/>Deciding to Defer - <a href="4-dtd.html#SP4">§4</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="identifier-syntax">current_session_number</span><span class="plain-syntax">++;</span>
|
|
<span class="plain-syntax"> </span><span class="identifier-syntax">EmitCode::inv</span><span class="plain-syntax">(</span><span class="identifier-syntax">OR_BIP</span><span class="plain-syntax">);</span>
|
|
<span class="plain-syntax"> </span><span class="identifier-syntax">EmitCode::down</span><span class="plain-syntax">();</span>
|
|
<span class="plain-syntax">}</span>
|
|
</pre>
|
|
<p class="commentary firstcommentary"><a id="SP4" class="paragraph-anchor"></a><b>§4. </b>Each variable records which "session" it belongs to, since there can be
|
|
multiple sessions happening at once:
|
|
</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">CompileConditions::add_calling</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">CompileConditions::add_calling</span></span>:<br/>Matching Action Patterns - <a href="2-map.html#SP5">§5</a><br/>Deciding to Defer - <a href="4-dtd.html#SP8_1">§8.1</a></span></button><span class="plain-syntax">(</span><span class="reserved-syntax">local_variable</span><span class="plain-syntax"> *</span><span class="identifier-syntax">lvar</span><span class="plain-syntax">) {</span>
|
|
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">current_session_number</span><span class="plain-syntax"> < </span><span class="constant-syntax">0</span><span class="plain-syntax">) </span><span class="identifier-syntax">internal_error</span><span class="plain-syntax">(</span><span class="string-syntax">"no PM session"</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">callings_in_condition_sp</span><span class="plain-syntax"> + </span><span class="constant-syntax">1</span><span class="plain-syntax"> == </span><span class="constant-syntax">MAX_CALLINGS_IN_MATCH</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="identifier-syntax">_p_</span><span class="plain-syntax">(</span><span class="identifier-syntax">BelievedImpossible</span><span class="plain-syntax">),</span>
|
|
<span class="plain-syntax"> </span><span class="string-syntax">"that makes too complicated a condition to test"</span><span class="plain-syntax">,</span>
|
|
<span class="plain-syntax"> </span><span class="string-syntax">"with all of those clauses involving 'called' values."</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">callings_session_number</span><span class="plain-syntax">[</span><span class="identifier-syntax">callings_in_condition_sp</span><span class="plain-syntax">] = </span><span class="identifier-syntax">current_session_number</span><span class="plain-syntax">;</span>
|
|
<span class="plain-syntax"> </span><span class="identifier-syntax">callings_in_condition</span><span class="plain-syntax">[</span><span class="identifier-syntax">callings_in_condition_sp</span><span class="plain-syntax">++] = </span><span class="identifier-syntax">lvar</span><span class="plain-syntax">;</span>
|
|
<span class="plain-syntax"> }</span>
|
|
<span class="plain-syntax">}</span>
|
|
</pre>
|
|
<p class="commentary firstcommentary"><a id="SP5" class="paragraph-anchor"></a><b>§5. </b>Now for the second operand of the <span class="extract"><span class="extract-syntax">OR_BIP</span></span>. If there weren't any callings,
|
|
we just compile <span class="extract"><span class="extract-syntax">false</span></span>. (It looks wasteful to have compiled "if (... or false)",
|
|
but in that event the use of <span class="extract"><span class="extract-syntax">OP_BIP</span></span> will be optimised out later: see
|
|
<a href="../pipeline-module/2-ero.html" class="internal">Eliminate Redundant Operations (in pipeline)</a>.) If there were callings, we default them.
|
|
</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">CompileConditions::end</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">CompileConditions::end</span></span>:<br/>Matching Action Patterns - <a href="2-map.html#SP3_5">§3.5</a><br/>Deciding to Defer - <a href="4-dtd.html#SP4">§4</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">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">current_session_number</span><span class="plain-syntax"> < </span><span class="constant-syntax">0</span><span class="plain-syntax">) </span><span class="identifier-syntax">internal_error</span><span class="plain-syntax">(</span><span class="string-syntax">"unstarted PM session"</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">NC</span><span class="plain-syntax"> = </span><span class="constant-syntax">0</span><span class="plain-syntax">, </span><span class="identifier-syntax">x</span><span class="plain-syntax"> = </span><span class="identifier-syntax">callings_in_condition_sp</span><span class="plain-syntax">, </span><span class="identifier-syntax">downs</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">while</span><span class="plain-syntax"> ((</span><span class="identifier-syntax">x</span><span class="plain-syntax"> > </span><span class="constant-syntax">0</span><span class="plain-syntax">) && (</span><span class="identifier-syntax">callings_session_number</span><span class="plain-syntax">[</span><span class="identifier-syntax">x</span><span class="plain-syntax">-1] == </span><span class="identifier-syntax">current_session_number</span><span class="plain-syntax">)) {</span>
|
|
<span class="plain-syntax"> </span><span class="identifier-syntax">NC</span><span class="plain-syntax">++;</span>
|
|
<span class="plain-syntax"> </span><span class="identifier-syntax">x</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">NC</span><span class="plain-syntax"> == </span><span class="constant-syntax">0</span><span class="plain-syntax">) {</span>
|
|
<span class="plain-syntax"> </span><span class="identifier-syntax">EmitCode::val_false</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="named-paragraph-container code-font"><a href="2-cc.html#SP5_1" class="named-paragraph-link"><span class="named-paragraph">Set the callings in this session to default values for their kinds</span><span class="named-paragraph-number">5.1</span></a></span><span class="plain-syntax">;</span>
|
|
<span class="plain-syntax"> }</span>
|
|
<span class="plain-syntax"> </span><span class="identifier-syntax">current_session_number</span><span class="plain-syntax">--;</span>
|
|
<span class="plain-syntax"> </span><span class="reserved-syntax">while</span><span class="plain-syntax"> (</span><span class="identifier-syntax">downs</span><span class="plain-syntax"> > </span><span class="constant-syntax">0</span><span class="plain-syntax">) { </span><span class="identifier-syntax">downs</span><span class="plain-syntax">--; </span><span class="identifier-syntax">EmitCode::up</span><span class="plain-syntax">(); }</span>
|
|
<span class="plain-syntax">}</span>
|
|
</pre>
|
|
<p class="commentary firstcommentary"><a id="SP5_1" class="paragraph-anchor"></a><b>§5.1. </b><span class="named-paragraph-container code-font"><span class="named-paragraph-defn">Set the callings in this session to default values for their kinds</span><span class="named-paragraph-number">5.1</span></span><span class="comment-syntax"> =</span>
|
|
</p>
|
|
|
|
<pre class="displayed-code all-displayed-code code-font">
|
|
<span class="plain-syntax"> </span><span class="identifier-syntax">EmitCode::inv</span><span class="plain-syntax">(</span><span class="identifier-syntax">SEQUENTIAL_BIP</span><span class="plain-syntax">);</span>
|
|
<span class="plain-syntax"> </span><span class="identifier-syntax">EmitCode::down</span><span class="plain-syntax">(); </span><span class="identifier-syntax">downs</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">NM</span><span class="plain-syntax"> = </span><span class="constant-syntax">0</span><span class="plain-syntax">, </span><span class="identifier-syntax">inner_downs</span><span class="plain-syntax"> = </span><span class="constant-syntax">0</span><span class="plain-syntax">;;</span>
|
|
<span class="plain-syntax"> </span><span class="reserved-syntax">while</span><span class="plain-syntax"> ((</span><span class="identifier-syntax">callings_in_condition_sp</span><span class="plain-syntax"> > </span><span class="constant-syntax">0</span><span class="plain-syntax">) &&</span>
|
|
<span class="plain-syntax"> (</span><span class="identifier-syntax">callings_session_number</span><span class="plain-syntax">[</span><span class="identifier-syntax">callings_in_condition_sp</span><span class="plain-syntax">-1] == </span><span class="identifier-syntax">current_session_number</span><span class="plain-syntax">)) {</span>
|
|
<span class="plain-syntax"> </span><span class="identifier-syntax">NM</span><span class="plain-syntax">++;</span>
|
|
<span class="plain-syntax"> </span><span class="reserved-syntax">local_variable</span><span class="plain-syntax"> *</span><span class="identifier-syntax">lvar</span><span class="plain-syntax"> = </span><span class="identifier-syntax">callings_in_condition</span><span class="plain-syntax">[</span><span class="identifier-syntax">callings_in_condition_sp</span><span class="plain-syntax">-1];</span>
|
|
<span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">NM</span><span class="plain-syntax"> < </span><span class="identifier-syntax">NC</span><span class="plain-syntax">) {</span>
|
|
<span class="plain-syntax"> </span><span class="identifier-syntax">EmitCode::inv</span><span class="plain-syntax">(</span><span class="identifier-syntax">SEQUENTIAL_BIP</span><span class="plain-syntax">);</span>
|
|
<span class="plain-syntax"> </span><span class="identifier-syntax">EmitCode::down</span><span class="plain-syntax">(); </span><span class="identifier-syntax">inner_downs</span><span class="plain-syntax">++;</span>
|
|
<span class="plain-syntax"> }</span>
|
|
<span class="plain-syntax"> </span><span class="identifier-syntax">EmitCode::inv</span><span class="plain-syntax">(</span><span class="identifier-syntax">STORE_BIP</span><span class="plain-syntax">);</span>
|
|
<span class="plain-syntax"> </span><span class="identifier-syntax">EmitCode::down</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">lvar_s</span><span class="plain-syntax"> = </span><a href="3-lv.html#SP1" class="function-link"><span class="function-syntax">LocalVariables::declare</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">lvar</span><span class="plain-syntax">);</span>
|
|
<span class="plain-syntax"> </span><span class="identifier-syntax">EmitCode::ref_symbol</span><span class="plain-syntax">(</span><span class="identifier-syntax">K_value</span><span class="plain-syntax">, </span><span class="identifier-syntax">lvar_s</span><span class="plain-syntax">);</span>
|
|
<span class="plain-syntax"> </span><span class="identifier-syntax">kind</span><span class="plain-syntax"> *</span><span class="identifier-syntax">K</span><span class="plain-syntax"> = </span><a href="3-lv.html#SP24" class="function-link"><span class="function-syntax">LocalVariables::kind</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">lvar</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">K</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">Kinds::Behaviour::is_object</span><span class="plain-syntax">(</span><span class="identifier-syntax">K</span><span class="plain-syntax">)) ||</span>
|
|
<span class="plain-syntax"> (</span><span class="identifier-syntax">Kinds::Behaviour::definite</span><span class="plain-syntax">(</span><span class="identifier-syntax">K</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">DefaultValues::val</span><span class="plain-syntax">(</span><span class="identifier-syntax">K</span><span class="plain-syntax">, </span><span class="identifier-syntax">EMPTY_WORDING</span><span class="plain-syntax">,</span>
|
|
<span class="plain-syntax"> </span><span class="string-syntax">"'called' value"</span><span class="plain-syntax">) != </span><span class="identifier-syntax">TRUE</span><span class="plain-syntax">))</span>
|
|
<span class="plain-syntax"> </span><span class="identifier-syntax">EmitCode::val_false</span><span class="plain-syntax">();</span>
|
|
<span class="plain-syntax"> </span><span class="identifier-syntax">EmitCode::up</span><span class="plain-syntax">();</span>
|
|
<span class="plain-syntax"> </span><span class="identifier-syntax">callings_in_condition_sp</span><span class="plain-syntax">--;</span>
|
|
<span class="plain-syntax"> }</span>
|
|
<span class="plain-syntax"> </span><span class="reserved-syntax">while</span><span class="plain-syntax"> (</span><span class="identifier-syntax">inner_downs</span><span class="plain-syntax"> > </span><span class="constant-syntax">0</span><span class="plain-syntax">) { </span><span class="identifier-syntax">inner_downs</span><span class="plain-syntax">--; </span><span class="identifier-syntax">EmitCode::up</span><span class="plain-syntax">(); }</span>
|
|
<span class="plain-syntax"> </span><span class="identifier-syntax">EmitCode::val_false</span><span class="plain-syntax">();</span>
|
|
</pre>
|
|
<ul class="endnotetexts"><li>This code is used in <a href="2-cc.html#SP5">§5</a>.</li></ul>
|
|
<nav role="progress"><div class="progresscontainer">
|
|
<ul class="progressbar"><li class="progressprev"><a href="2-cl.html">❮</a></li><li class="progresschapter"><a href="P-wtmd.html">P</a></li><li class="progresschapter"><a href="1-im.html">1</a></li><li class="progresscurrentchapter">2</li><li class="progresssection"><a href="2-cv.html">cv</a></li><li class="progresssection"><a href="2-cr.html">cr</a></li><li class="progresssection"><a href="2-cl.html">cl</a></li><li class="progresscurrent">cc</li><li class="progresssection"><a href="2-map.html">map</a></li><li class="progresssection"><a href="2-mgap.html">mgap</a></li><li class="progresschapter"><a href="3-sf.html">3</a></li><li class="progresschapter"><a href="4-cs.html">4</a></li><li class="progresschapter"><a href="5-cbal.html">5</a></li><li class="progressnext"><a href="2-map.html">❯</a></li></ul></div>
|
|
</nav><!--End of weave-->
|
|
|
|
</main>
|
|
</body>
|
|
</html>
|
|
|