ifhub/inform7
1
0
Fork 0
mirror of https://github.com/ganelson/inform.git synced 2024-07-05 08:34:22 +03:00
Code Issues Projects Releases Wiki Activity
inform7/docs/BasicInformKit/S-rlb.html
Graham Nelson 1268a0f40e Colonised
2020-04-14 17:56:54 +01:00

350 lines
36 KiB
HTML
Raw Blame History

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title>Rulebooks Template</title>
<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="../inweb.css" rel="stylesheet" rev="stylesheet" type="text/css">
</head>
<body>
<nav role="navigation">
<h1><a href="../index.html">
<img src="../docs-src/Figures/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>Extensions</h2><ul>
<li><a href="../basic_inform/index.html">basic_inform</a></li>
<li><a href="../standard_rules/index.html">standard_rules</a></li>
</ul><h2>Kits</h2><ul>
<li><a href="index.html"><span class="selectedlink">BasicInformKit</span></a></li>
<li><a href="../BasicInformExtrasKit/index.html">BasicInformExtrasKit</a></li>
<li><a href="../CommandParserKit/index.html">CommandParserKit</a></li>
<li><a href="../EnglishLanguageKit/index.html">EnglishLanguageKit</a></li>
<li><a href="../WorldModelKit/index.html">WorldModelKit</a></li>
</ul>
</nav>
<main role="main">
<!--Weave of 'Rulebooks Template' generated by 7-->
<ul class="crumbs"><li><a href="../index.html">Home</a></li><li><a href="../extensions.html">Kits</a></li><li><a href="index.html">BasicInformKit</a></li><li><b>Rulebooks Template</b></li></ul><p class="purpose">To work through the rules in a rulebook until a decision is made.</p>
<ul class="toc"><li><a href="#SP1">&#167;1. Latest Rule Result</a></li><li><a href="#SP2">&#167;2. Following</a></li><li><a href="#SP3">&#167;3. Specifying Outcomes</a></li><li><a href="#SP4">&#167;4. Discovering Outcomes</a></li><li><a href="#SP5">&#167;5. Printing Rule Names</a></li><li><a href="#SP6">&#167;6. Casting</a></li><li><a href="#SP7">&#167;7. Debugging</a></li><li><a href="#SP8">&#167;8. The Default Rule</a></li></ul><hr class="tocbar">
<p class="inwebparagraph"><a id="SP1"></a><b>&#167;1. Latest Rule Result. </b>This used to be a large data structure which kept track of the effect of
procedural rules, but in January 2011 procedurals were abolished. It retains
only one purpose: as a place to record the result of the most recently
completed rule. This used to sit on the top of the stack, and is now the
only thing which ever sits on it. So the "stack" has just one 3-word
record now. The meanings of these are as follows. The first word is one of
the following:
</p>
<p class="inwebparagraph"></p>
<ul class="items"><li>(1) <code class="display"><span class="extract">RS_SUCCEEDS</span></code> indicates that the most recent rule or rulebook processed
ended in success. Word 2 is <code class="display"><span class="extract">false</span></code> if there's no value, or the kind if there
is, in which case word 3 contains the value itself.
</li><li>(2) <code class="display"><span class="extract">RS_FAILS</span></code> is similar, but for a failure. Note that failures can also
return values.
</li><li>(3) <code class="display"><span class="extract">RS_NEITHER</span></code> is similar except that it cannot return any value, so that
words 2 and 3 are meaningless.
</li></ul>
<pre class="display">
<span class="reserved">Constant</span><span class="plain"> </span><span class="identifier">RS_NEITHER</span><span class="plain"> = </span><span class="constant">0</span><span class="plain">;</span>
<span class="reserved">Constant</span><span class="plain"> </span><span class="identifier">RS_SUCCEEDS</span><span class="plain"> = </span><span class="constant">1</span><span class="plain">;</span>
<span class="reserved">Constant</span><span class="plain"> </span><span class="identifier">RS_FAILS</span><span class="plain"> = </span><span class="constant">2</span><span class="plain">;</span>
<span class="reserved">Array</span><span class="plain"> </span><span class="identifier">latest_rule_result</span><span class="plain"> --&gt; </span><span class="constant">3</span><span class="plain">;</span>
<span class="plain">[ </span><span class="identifier">RecordRuleOutcome</span><span class="plain"> </span><span class="identifier">usage</span><span class="plain"> </span><span class="identifier">rule1</span><span class="plain"> </span><span class="identifier">rule2</span><span class="plain">;</span>
<span class="reserved">if</span><span class="plain"> ((</span><span class="identifier">latest_rule_result</span><span class="plain">--&gt;0 == </span><span class="identifier">RS_SUCCEEDS</span><span class="plain"> </span><span class="reserved">or</span><span class="plain"> </span><span class="identifier">RS_FAILS</span><span class="plain">) &amp;&amp;</span>
<span class="plain">(</span><span class="identifier">KOVIsBlockValue</span><span class="plain">(</span><span class="identifier">latest_rule_result</span><span class="plain">--&gt;1)))</span>
<span class="identifier">BlkValueFree</span><span class="plain">(</span><span class="identifier">latest_rule_result</span><span class="plain">--&gt;2);</span>
<span class="reserved">if</span><span class="plain"> ((</span><span class="identifier">usage</span><span class="plain"> == </span><span class="identifier">RS_SUCCEEDS</span><span class="plain"> </span><span class="reserved">or</span><span class="plain"> </span><span class="identifier">RS_FAILS</span><span class="plain">) &amp;&amp; (</span><span class="identifier">KOVIsBlockValue</span><span class="plain">(</span><span class="identifier">rule1</span><span class="plain">)))</span>
<span class="identifier">rule2</span><span class="plain"> = </span><span class="identifier">BlkValueCopy</span><span class="plain">(</span><span class="identifier">BlkValueCreate</span><span class="plain">(</span><span class="identifier">rule1</span><span class="plain">), </span><span class="identifier">rule2</span><span class="plain">);</span>
<span class="identifier">latest_rule_result</span><span class="plain">--&gt;0 = </span><span class="identifier">usage</span><span class="plain">;</span>
<span class="identifier">latest_rule_result</span><span class="plain">--&gt;1 = </span><span class="identifier">rule1</span><span class="plain">;</span>
<span class="identifier">latest_rule_result</span><span class="plain">--&gt;2 = </span><span class="identifier">rule2</span><span class="plain">;</span>
<span class="plain">];</span>
</pre>
<p class="inwebparagraph"></p>
<p class="inwebparagraph"><a id="SP2"></a><b>&#167;2. Following. </b>Until January 2011, there were two ways to invoke a rulebook: to "follow" it
or simply "process" it. With the demise of procedural rules, these became
equivalent.
</p>
<p class="inwebparagraph">In the early days of Inform 7, stack usage became a serious issue since
some forms of the Frotz Z-machine interpreter provided only 4K of stack
by default. ("Only" 4K. In the mid-1980s, one of the obstacles facing
IF authors at Infocom was the need to get the stack usage down to fewer
than 600 bytes in order that the story file could be run on the smaller
home computers of the day.) <code class="display"><span class="extract">FollowRulebook</span></code> was the major consumer of
stack space, on average, because of its frequent recursion. Now that the
process is simpler, this has become less problematic, since the routine
now has fewer local variables.
</p>
<p class="inwebparagraph"><code class="display"><span class="extract">FollowRulebook</span></code> takes three arguments, of which only the first is
compulsory:
</p>
<p class="inwebparagraph"></p>
<ul class="items"><li>(a) The <code class="display"><span class="extract">rulebook</span></code> is an I7 value of kind "rule", which means it can be
either the ID number of a rulebook &mdash; from 0 up to \(N-1\), where \(N\) is the
number of rulebooks compiled by Inform, typically about 600 &mdash; or else the
address of a routine representing an individual rule.
</li><li>(b) The <code class="display"><span class="extract">parameter</span></code> supplied to the rulebook. Much as arguments can be supplied
to a function in a conventional language's function call, so a parameter can be
supplied whenever a rulebook is invoked.
</li><li>(c) <code class="display"><span class="extract">no_paragraph_skips</span></code> is a flag: if explicitly set <code class="display"><span class="extract">true</span></code>, then the rulebook
is run with paragraph breaking suppressed. This is the process by which
paragraph division points are placed between rules, so that if two rules both
print text then a paragraph break appears between. While that is appropriate
for rulebooks attached to actions or for "every turn" rules, it is disastrous
for rulebooks attached to activities such as "printing the name of
something".
</li></ul>
<p class="inwebparagraph"><code class="display"><span class="extract">FollowRulebook</span></code> returns <code class="display"><span class="extract">R</span></code> if rule <code class="display"><span class="extract">R</span></code> in the rulebook (or rule) chose to
"succeed" or "fail", and <code class="display"><span class="extract">false</span></code> if it made no choice. (To repeat: if
the rule explicitly fails, then <code class="display"><span class="extract">FollowRulebook</span></code> returns <code class="display"><span class="extract">true</span></code>. It's easy
to write plausible-looking code which goes wrong because it assumes that the
return value is success vs. failure.) The outcome of <code class="display"><span class="extract">FollowRulebook</span></code> is
stored as described above: thus the most recent rule or rulebook succeeded
or failed if &mdash;
</p>
<pre class="display">
<span class="plain">(</span><span class="identifier">latest_rule_result</span><span class="plain">--&gt;0 == </span><span class="identifier">RS_SUCCEEDS</span><span class="plain">)</span>
<span class="plain">(</span><span class="identifier">latest_rule_result</span><span class="plain">--&gt;0 == </span><span class="identifier">RS_FAILS</span><span class="plain">)</span>
</pre>
<p class="inwebparagraph">and otherwise there was no decision.
</p>
<pre class="display">
<span class="identifier">Global</span><span class="plain"> </span><span class="identifier">process_rulebook_count</span><span class="plain">; </span><span class="comment">Depth of processing recursion</span>
<span class="identifier">Global</span><span class="plain"> </span><span class="identifier">debugging_rules</span><span class="plain"> = </span><span class="reserved">false</span><span class="plain">; </span><span class="comment">Are we tracing rule invocations?</span>
<span class="plain">[ </span><span class="identifier">FollowRulebook</span><span class="plain"> </span><span class="identifier">rulebook</span><span class="plain"> </span><span class="identifier">parameter</span><span class="plain"> </span><span class="identifier">no_paragraph_skips</span>
<span class="identifier">rv</span><span class="plain"> </span><span class="identifier">ss</span><span class="plain"> </span><span class="identifier">spv</span><span class="plain">;</span>
<span class="identifier">ss</span><span class="plain"> = </span><span class="identifier">self</span><span class="plain">;</span>
<span class="reserved">if</span><span class="plain"> ((</span><span class="identifier">Protect_I7_Arrays</span><span class="plain">--&gt;0 ~= </span><span class="constant">16339</span><span class="plain">) || (</span><span class="identifier">Protect_I7_Arrays</span><span class="plain">--&gt;1 ~= </span><span class="constant">12345</span><span class="plain">)) {</span>
<span class="reserved">print</span><span class="plain"> </span><span class="string">"^^*** Fatal programming error: I7 arrays corrupted ***^^"</span><span class="plain">;</span>
<span class="plain">@</span><span class="reserved">quit</span><span class="plain">;</span>
<span class="plain">}</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">parameter</span><span class="plain">) { </span><span class="identifier">self</span><span class="plain"> = </span><span class="identifier">parameter</span><span class="plain">; </span><span class="identifier">parameter_object</span><span class="plain"> = </span><span class="identifier">parameter</span><span class="plain">; }</span>
<span class="identifier">spv</span><span class="plain"> = </span><span class="identifier">parameter_value</span><span class="plain">; </span><span class="identifier">parameter_value</span><span class="plain"> = </span><span class="identifier">parameter</span><span class="plain">;</span>
<span class="comment">we won't need parameter again, so can reuse it</span>
<span class="identifier">parameter</span><span class="plain"> = </span><span class="identifier">debugging_rules</span><span class="plain">;</span>
<span class="plain">#</span><span class="identifier">ifndef</span><span class="plain"> </span><span class="identifier">MEMORY_ECONOMY</span><span class="plain">;</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">debugging_rules</span><span class="plain">) {</span>
<span class="identifier">DebugRulebooks</span><span class="plain">(</span><span class="identifier">rulebook</span><span class="plain">, </span><span class="identifier">parameter</span><span class="plain">);</span>
<span class="identifier">process_rulebook_count</span><span class="plain"> = </span><span class="identifier">process_rulebook_count</span><span class="plain"> + </span><span class="identifier">debugging_rules</span><span class="plain">;</span>
<span class="plain">}</span>
<span class="plain">#</span><span class="identifier">endif</span><span class="plain">;</span>
<span class="reserved">if</span><span class="plain"> ((</span><span class="identifier">rulebook</span><span class="plain"> &gt;= </span><span class="constant">0</span><span class="plain">) &amp;&amp; (</span><span class="identifier">rulebook</span><span class="plain"> &lt; </span><span class="identifier">NUMBER_RULEBOOKS_CREATED</span><span class="plain">)) {</span>
<span class="identifier">rv</span><span class="plain"> = </span><span class="identifier">rulebooks_array</span><span class="plain">--&gt;</span><span class="identifier">rulebook</span><span class="plain">;</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">rv</span><span class="plain"> ~= </span><span class="identifier">EMPTY_RULEBOOK</span><span class="plain">) {</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">rulebook</span><span class="plain"> ~= </span><span class="identifier">ACTION_PROCESSING_RB</span><span class="plain">) </span><span class="identifier">MStack_CreateRBVars</span><span class="plain">(</span><span class="identifier">rulebook</span><span class="plain">);</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">say__p</span><span class="plain">) </span><span class="identifier">RulebookParBreak</span><span class="plain">(</span><span class="identifier">no_paragraph_skips</span><span class="plain">);</span>
<span class="identifier">rv</span><span class="plain"> = </span><span class="identifier">rv</span><span class="plain">(</span><span class="identifier">no_paragraph_skips</span><span class="plain">);</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">rulebook</span><span class="plain"> ~= </span><span class="identifier">ACTION_PROCESSING_RB</span><span class="plain">) </span><span class="identifier">MStack_DestroyRBVars</span><span class="plain">(</span><span class="identifier">rulebook</span><span class="plain">);</span>
<span class="plain">} </span><span class="reserved">else</span><span class="plain"> {</span>
<span class="identifier">rv</span><span class="plain"> = </span><span class="constant">0</span><span class="plain">;</span>
<span class="plain">}</span>
<span class="plain">} </span><span class="reserved">else</span><span class="plain"> {</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">say__p</span><span class="plain">) </span><span class="identifier">RulebookParBreak</span><span class="plain">(</span><span class="identifier">no_paragraph_skips</span><span class="plain">);</span>
<span class="identifier">rv</span><span class="plain"> = </span><span class="reserved">indirect</span><span class="plain">(</span><span class="identifier">rulebook</span><span class="plain">);</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">rv</span><span class="plain"> == </span><span class="constant">2</span><span class="plain">) </span><span class="identifier">rv</span><span class="plain"> = </span><span class="identifier">reason_the_action_failed</span><span class="plain">;</span>
<span class="reserved">else</span><span class="plain"> </span><span class="reserved">if</span><span class="plain"> (</span><span class="identifier">rv</span><span class="plain">) </span><span class="identifier">rv</span><span class="plain"> = </span><span class="identifier">rulebook</span><span class="plain">;</span>
<span class="plain">}</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">rv</span><span class="plain">) {</span>
<span class="plain">#</span><span class="identifier">ifndef</span><span class="plain"> </span><span class="identifier">MEMORY_ECONOMY</span><span class="plain">;</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">debugging_rules</span><span class="plain">) {</span>
<span class="identifier">process_rulebook_count</span><span class="plain"> = </span><span class="identifier">process_rulebook_count</span><span class="plain"> - </span><span class="identifier">debugging_rules</span><span class="plain">;</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">process_rulebook_count</span><span class="plain"> &lt; </span><span class="constant">0</span><span class="plain">) </span><span class="identifier">process_rulebook_count</span><span class="plain"> = </span><span class="constant">0</span><span class="plain">;</span>
<span class="reserved">spaces</span><span class="plain">(2*</span><span class="identifier">process_rulebook_count</span><span class="plain">);</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">latest_rule_result</span><span class="plain">--&gt;0 == </span><span class="identifier">RS_SUCCEEDS</span><span class="plain">) </span><span class="reserved">print</span><span class="plain"> </span><span class="string">"[stopped: success]^"</span><span class="plain">;</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">latest_rule_result</span><span class="plain">--&gt;0 == </span><span class="identifier">RS_FAILS</span><span class="plain">) </span><span class="reserved">print</span><span class="plain"> </span><span class="string">"[stopped: fail]^"</span><span class="plain">;</span>
<span class="plain">}</span>
<span class="plain">#</span><span class="identifier">endif</span><span class="plain">;</span>
<span class="plain">} </span><span class="reserved">else</span><span class="plain"> {</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">debugging_rules</span><span class="plain">)</span>
<span class="identifier">process_rulebook_count</span><span class="plain"> = </span><span class="identifier">process_rulebook_count</span><span class="plain"> - </span><span class="identifier">debugging_rules</span><span class="plain">;</span>
<span class="identifier">latest_rule_result</span><span class="plain">--&gt;0 = </span><span class="identifier">RS_NEITHER</span><span class="plain">;</span>
<span class="plain">}</span>
<span class="identifier">debugging_rules</span><span class="plain"> = </span><span class="identifier">parameter</span><span class="plain">;</span>
<span class="identifier">self</span><span class="plain"> = </span><span class="identifier">ss</span><span class="plain">; </span><span class="identifier">parameter_value</span><span class="plain"> = </span><span class="identifier">spv</span><span class="plain">;</span>
<span class="reserved">return</span><span class="plain"> </span><span class="identifier">rv</span><span class="plain">;</span>
<span class="plain">];</span>
<span class="plain">[ </span><span class="identifier">RulebookParBreak</span><span class="plain"> </span><span class="identifier">no_paragraph_skips</span><span class="plain">;</span>
<span class="reserved">if</span><span class="plain"> ((</span><span class="identifier">no_paragraph_skips</span><span class="plain"> == </span><span class="reserved">false</span><span class="plain">) &amp;&amp; (</span><span class="identifier">say__pc</span><span class="plain"> &amp; </span><span class="identifier">PARA_NORULEBOOKBREAKS</span><span class="plain"> == </span><span class="constant">0</span><span class="plain">))</span>
<span class="identifier">DivideParagraphPoint</span><span class="plain">();</span>
<span class="plain">];</span>
</pre>
<p class="inwebparagraph"></p>
<p class="inwebparagraph"><a id="SP3"></a><b>&#167;3. Specifying Outcomes. </b>The following provide ways for rules to succeed, fail or decline to do
either.
</p>
<p class="inwebparagraph"><code class="display"><span class="extract">SetRulebookOutcome</span></code> is a little different: it changes the outcome state
of the most recent rule completed, not the current one. (It's used only
when saving and restoring this in the actions machinery: rules should not
call it.)
</p>
<pre class="display">
<span class="plain">[ </span><span class="identifier">ActRulebookSucceeds</span><span class="plain"> </span><span class="identifier">rule_id</span><span class="plain">;</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">rule_id</span><span class="plain">) </span><span class="identifier">reason_the_action_failed</span><span class="plain"> = </span><span class="identifier">rule_id</span><span class="plain">;</span>
<span class="identifier">RulebookSucceeds</span><span class="plain">();</span>
<span class="plain">];</span>
<span class="plain">[ </span><span class="identifier">ActRulebookFails</span><span class="plain"> </span><span class="identifier">rule_id</span><span class="plain">;</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">rule_id</span><span class="plain">) </span><span class="identifier">reason_the_action_failed</span><span class="plain"> = </span><span class="identifier">rule_id</span><span class="plain">;</span>
<span class="identifier">RulebookFails</span><span class="plain">();</span>
<span class="plain">];</span>
<span class="plain">[ </span><span class="identifier">RulebookSucceeds</span><span class="plain"> </span><span class="identifier">weak_kind</span><span class="plain"> </span><span class="identifier">value</span><span class="plain">;</span>
<span class="identifier">RecordRuleOutcome</span><span class="plain">(</span><span class="identifier">RS_SUCCEEDS</span><span class="plain">, </span><span class="identifier">weak_kind</span><span class="plain">, </span><span class="identifier">value</span><span class="plain">);</span>
<span class="plain">];</span>
<span class="plain">[ </span><span class="identifier">RulebookFails</span><span class="plain"> </span><span class="identifier">weak_kind</span><span class="plain"> </span><span class="identifier">value</span><span class="plain">;</span>
<span class="identifier">RecordRuleOutcome</span><span class="plain">(</span><span class="identifier">RS_FAILS</span><span class="plain">, </span><span class="identifier">weak_kind</span><span class="plain">, </span><span class="identifier">value</span><span class="plain">);</span>
<span class="plain">];</span>
<span class="plain">[ </span><span class="identifier">RuleHasNoOutcome</span><span class="plain">;</span>
<span class="identifier">RecordRuleOutcome</span><span class="plain">(</span><span class="identifier">RS_NEITHER</span><span class="plain">, </span><span class="constant">0</span><span class="plain">, </span><span class="constant">0</span><span class="plain">);</span>
<span class="plain">];</span>
<span class="plain">[ </span><span class="identifier">SetRulebookOutcome</span><span class="plain"> </span><span class="identifier">a</span><span class="plain">;</span>
<span class="identifier">latest_rule_result</span><span class="plain">--&gt;0 = </span><span class="identifier">a</span><span class="plain">;</span>
<span class="plain">];</span>
</pre>
<p class="inwebparagraph"></p>
<p class="inwebparagraph"><a id="SP4"></a><b>&#167;4. Discovering Outcomes. </b>And here is how to tell what the results were.
</p>
<pre class="display">
<span class="plain">[ </span><span class="identifier">RulebookOutcome</span><span class="plain"> </span><span class="identifier">a</span><span class="plain">;</span>
<span class="identifier">a</span><span class="plain"> = </span><span class="identifier">latest_rule_result</span><span class="plain">--&gt;0;</span>
<span class="reserved">if</span><span class="plain"> ((</span><span class="identifier">a</span><span class="plain"> == </span><span class="identifier">RS_FAILS</span><span class="plain">) || (</span><span class="identifier">a</span><span class="plain"> == </span><span class="identifier">RS_SUCCEEDS</span><span class="plain">)) </span><span class="reserved">return</span><span class="plain"> </span><span class="identifier">a</span><span class="plain">;</span>
<span class="reserved">return</span><span class="plain"> </span><span class="identifier">RS_NEITHER</span><span class="plain">;</span>
<span class="plain">];</span>
<span class="plain">[ </span><span class="identifier">RulebookFailed</span><span class="plain">;</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">latest_rule_result</span><span class="plain">--&gt;0 == </span><span class="identifier">RS_FAILS</span><span class="plain">) </span><span class="reserved">rtrue</span><span class="plain">; </span><span class="reserved">rfalse</span><span class="plain">;</span>
<span class="plain">];</span>
<span class="plain">[ </span><span class="identifier">RulebookSucceeded</span><span class="plain">;</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">latest_rule_result</span><span class="plain">--&gt;0 == </span><span class="identifier">RS_SUCCEEDS</span><span class="plain">) </span><span class="reserved">rtrue</span><span class="plain">; </span><span class="reserved">rfalse</span><span class="plain">;</span>
<span class="plain">];</span>
<span class="plain">[ </span><span class="identifier">ResultOfRule</span><span class="plain"> </span><span class="identifier">RB</span><span class="plain"> </span><span class="identifier">V</span><span class="plain"> </span><span class="identifier">F</span><span class="plain"> </span><span class="identifier">K</span><span class="plain"> </span><span class="identifier">a</span><span class="plain">;</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">RB</span><span class="plain">) </span><span class="identifier">FollowRulebook</span><span class="plain">(</span><span class="identifier">RB</span><span class="plain">, </span><span class="identifier">V</span><span class="plain">, </span><span class="identifier">F</span><span class="plain">);</span>
<span class="identifier">a</span><span class="plain"> = </span><span class="identifier">latest_rule_result</span><span class="plain">--&gt;0;</span>
<span class="reserved">if</span><span class="plain"> ((</span><span class="identifier">a</span><span class="plain"> == </span><span class="identifier">RS_FAILS</span><span class="plain">) || (</span><span class="identifier">a</span><span class="plain"> == </span><span class="identifier">RS_SUCCEEDS</span><span class="plain">)) {</span>
<span class="identifier">a</span><span class="plain"> = </span><span class="identifier">latest_rule_result</span><span class="plain">--&gt;1;</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">a</span><span class="plain">) </span><span class="reserved">return</span><span class="plain"> </span><span class="identifier">latest_rule_result</span><span class="plain">--&gt;2;</span>
<span class="plain">}</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">K</span><span class="plain">) </span><span class="reserved">return</span><span class="plain"> </span><span class="identifier">DefaultValueOfKOV</span><span class="plain">(</span><span class="identifier">K</span><span class="plain">);</span>
<span class="reserved">return</span><span class="plain"> </span><span class="constant">0</span><span class="plain">;</span>
<span class="plain">];</span>
</pre>
<p class="inwebparagraph"></p>
<p class="inwebparagraph"><a id="SP5"></a><b>&#167;5. Printing Rule Names. </b>This is the I6 printing rule used for a value of kind "rule", which as
noted above can either be rulebook ID numbers in the range 0 to \(N-1\) or
are addresses of individual rules.
</p>
<p class="inwebparagraph">Names of rules and rulebooks take up a fair amount of space, and one of the
main memory economies enforced by the "Use memory economy" option is to
omit the necessary arrays. (It's not the text which is the problem so
much as the table of addresses pointing to that text, which has to live in
precious readable memory on the Z-machine.)
</p>
<p class="inwebparagraph"><a id="SP6"></a><b>&#167;6. Casting. </b>Nothing needs to be done to a rulebook value to make it a rule value.
</p>
<pre class="display">
<span class="plain">[ </span><span class="identifier">RULEBOOK_TY_to_RULE_TY</span><span class="plain"> </span><span class="identifier">r</span><span class="plain">;</span>
<span class="reserved">return</span><span class="plain"> </span><span class="identifier">r</span><span class="plain">;</span>
<span class="plain">];</span>
</pre>
<p class="inwebparagraph"></p>
<p class="inwebparagraph"><a id="SP7"></a><b>&#167;7. Debugging. </b>Two modest routines to print out the names of rules and rulebooks when they
occur, in so far as memory economy allows this.
</p>
<pre class="display">
<span class="plain">[ </span><span class="identifier">DebugRulebooks</span><span class="plain"> </span><span class="identifier">subs</span><span class="plain"> </span><span class="identifier">parameter</span><span class="plain"> </span><span class="identifier">i</span><span class="plain">;</span>
<span class="reserved">spaces</span><span class="plain">(2*</span><span class="identifier">process_rulebook_count</span><span class="plain">);</span>
<span class="reserved">print</span><span class="plain"> </span><span class="string">"["</span><span class="plain">, (</span><span class="identifier">RulePrintingRule</span><span class="plain">) </span><span class="identifier">subs</span><span class="plain">;</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">parameter</span><span class="plain">) </span><span class="reserved">print</span><span class="plain"> </span><span class="string">" / on O"</span><span class="plain">, </span><span class="identifier">parameter</span><span class="plain">;</span>
<span class="reserved">print</span><span class="plain"> </span><span class="string">"]^"</span><span class="plain">;</span>
<span class="plain">];</span>
<span class="plain">[ </span><span class="identifier">DB_Rule</span><span class="plain"> </span><span class="identifier">R</span><span class="plain"> </span><span class="identifier">N</span><span class="plain"> </span><span class="identifier">blocked</span><span class="plain">;</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">R</span><span class="plain">==0) </span><span class="reserved">return</span><span class="plain">;</span>
<span class="reserved">print</span><span class="plain"> </span><span class="string">"[Rule ~"</span><span class="plain">, (</span><span class="identifier">RulePrintingRule</span><span class="plain">) </span><span class="identifier">R</span><span class="plain">, </span><span class="string">"~ "</span><span class="plain">;</span>
<span class="plain">#</span><span class="identifier">ifdef</span><span class="plain"> </span><span class="identifier">NUMBERED_RULES</span><span class="plain">; </span><span class="reserved">print</span><span class="plain"> </span><span class="string">"("</span><span class="plain">, </span><span class="identifier">N</span><span class="plain">, </span><span class="string">") "</span><span class="plain">; #</span><span class="identifier">endif</span><span class="plain">;</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">blocked</span><span class="plain"> == </span><span class="reserved">false</span><span class="plain">) </span><span class="string">"applies.]"</span><span class="plain">;</span>
<span class="reserved">print</span><span class="plain"> </span><span class="string">"does not apply (wrong "</span><span class="plain">;</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">blocked</span><span class="plain"> == </span><span class="constant">1</span><span class="plain">) </span><span class="reserved">print</span><span class="plain"> </span><span class="string">"scene"</span><span class="plain">;</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">blocked</span><span class="plain"> == </span><span class="constant">2</span><span class="plain">) </span><span class="reserved">print</span><span class="plain"> </span><span class="string">"action"</span><span class="plain">;</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">blocked</span><span class="plain"> == </span><span class="constant">3</span><span class="plain">) </span><span class="reserved">print</span><span class="plain"> </span><span class="string">"actor"</span><span class="plain">;</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">blocked</span><span class="plain"> == </span><span class="constant">4</span><span class="plain">) </span><span class="reserved">print</span><span class="plain"> </span><span class="string">"context"</span><span class="plain">;</span>
<span class="reserved">print</span><span class="plain"> </span><span class="string">").]^"</span><span class="plain">;</span>
<span class="plain">];</span>
</pre>
<p class="inwebparagraph"></p>
<p class="inwebparagraph"><a id="SP8"></a><b>&#167;8. The Default Rule. </b></p>
<pre class="display">
<span class="plain">[ </span><span class="identifier">LITTLE_USED_DO_NOTHING_R</span><span class="plain">; </span><span class="reserved">rfalse</span><span class="plain">; ];</span>
</pre>
<p class="inwebparagraph"></p>
<hr class="tocbar">
<ul class="toc"><li><a href="S-mst.html">Back to 'MStack Template'</a></li><li><a href="S-flx.html">Continue with 'Flex Template'</a></li></ul><hr class="tocbar">
<!--End of weave-->
<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>
</main>
</body>
</html>
Reference in a new issue View git blame Copy permalink