ifhub/inform7
1
0
Fork 0
mirror of https://github.com/ganelson/inform.git synced 2024-07-08 18:14:21 +03:00
Code Issues Projects Releases Wiki Activity
inform7/docs/words-module/4-nw.html
Graham Nelson d8e8d824cc Tidied compilation modules
2019-04-22 15:42:10 +01:00

286 lines
38 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>3/idn</title>
<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>
<!--Weave of '4/nw' generated by 7-->
<ul class="crumbs"><li><a href="../webs.html">&#9733;</a></li><li><a href="index.html">words</a></li><li><a href="index.html#4">Chapter 4: Parsing</a></li><li><b>Numbered Words</b></li></ul><p class="purpose">Some utilities for handling single words referred to by number.</p>
<ul class="toc"><li><a href="#SP1">&#167;1. Comparisons</a></li><li><a href="#SP3">&#167;3. Correct use of text substitutions</a></li><li><a href="#SP5">&#167;5. Casing and sentence division</a></li><li><a href="#SP8">&#167;8. Dequoting literal text</a></li><li><a href="#SP9">&#167;9. Dictionary words</a></li></ul><hr class="tocbar">
<p class="inwebparagraph"><a id="SP1"></a><b>&#167;1. Comparisons. </b>Comparison of the word at a given numbered position against some known
word, say "rulebook", must be done very quickly. The whole point of the
vocabulary bank identifying each distinct word was to enable this to be
done by a single comparison of pointers: and to avoid the overhead of a
function call, we perform this with macros.
</p>
<pre class="definitions">
<span class="definitionkeyword">define</span> <span class="identifier">compare_word</span><span class="plain">(</span><span class="identifier">w</span><span class="plain">, </span><span class="identifier">voc</span><span class="plain">) (</span><span class="functiontext">Lexer::word</span><span class="plain">(</span><span class="identifier">w</span><span class="plain">) == (</span><span class="identifier">voc</span><span class="plain">))</span>
<span class="definitionkeyword">define</span> <span class="identifier">compare_words</span><span class="plain">(</span><span class="identifier">w1</span><span class="plain">, </span><span class="identifier">w2</span><span class="plain">) (</span><span class="functiontext">Lexer::word</span><span class="plain">(</span><span class="identifier">w1</span><span class="plain">) == </span><span class="functiontext">Lexer::word</span><span class="plain">(</span><span class="identifier">w2</span><span class="plain">))</span>
<span class="definitionkeyword">define</span> <span class="identifier">compare_words_cs</span><span class="plain">(</span><span class="identifier">w1</span><span class="plain">, </span><span class="identifier">w2</span><span class="plain">) (</span><span class="identifier">Wide::cmp</span><span class="plain">(</span><span class="functiontext">Lexer::word_raw_text</span><span class="plain">(</span><span class="identifier">w1</span><span class="plain">), </span><span class="functiontext">Lexer::word_raw_text</span><span class="plain">(</span><span class="identifier">w2</span><span class="plain">)) == 0)</span>
</pre>
<p class="inwebparagraph"><a id="SP2"></a><b>&#167;2. </b>We can also, more slowly, perform a direct string comparison. If carried
out on the original, raw, text, this will be case sensitive &mdash; which is
usually wrong for Inform purposes. On the treated text, however, we are
comparing a case-normalised version of the original word, which is likely
to be safely case insensitive comparison, provided that the content of <code class="display"><span class="extract">t</span></code>
is also normalised.
</p>
<pre class="display">
<span class="reserved">int</span><span class="plain"> </span><span class="functiontext">Word::compare_by_strcmp</span><span class="plain">(</span><span class="reserved">int</span><span class="plain"> </span><span class="identifier">w</span><span class="plain">, </span><span class="identifier">wchar_t</span><span class="plain"> *</span><span class="identifier">t</span><span class="plain">) {</span>
<span class="reserved">return</span><span class="plain"> (</span><span class="identifier">Wide::cmp</span><span class="plain">(</span><span class="functiontext">Lexer::word_text</span><span class="plain">(</span><span class="identifier">w</span><span class="plain">), </span><span class="identifier">t</span><span class="plain">) == 0);</span>
<span class="plain">}</span>
<span class="reserved">int</span><span class="plain"> </span><span class="functiontext">Word::compare_raw_by_strcmp</span><span class="plain">(</span><span class="reserved">int</span><span class="plain"> </span><span class="identifier">w</span><span class="plain">, </span><span class="identifier">wchar_t</span><span class="plain"> *</span><span class="identifier">t</span><span class="plain">) {</span>
<span class="reserved">return</span><span class="plain"> (</span><span class="identifier">Wide::cmp</span><span class="plain">(</span><span class="functiontext">Lexer::word_raw_text</span><span class="plain">(</span><span class="identifier">w</span><span class="plain">), </span><span class="identifier">t</span><span class="plain">) == 0);</span>
<span class="plain">}</span>
</pre>
<p class="inwebparagraph"></p>
<p class="endnote">The function Word::compare_by_strcmp is used in 4/bn (<a href="4-bn.html#SP7">&#167;7</a>).</p>
<p class="endnote">The function Word::compare_raw_by_strcmp appears nowhere else.</p>
<p class="inwebparagraph"><a id="SP3"></a><b>&#167;3. Correct use of text substitutions. </b>If a "word" is going to be quoted literal text, then it has to use the
characters <code class="display"><span class="extract">[</span></code> and <code class="display"><span class="extract">]</span></code> in a matched way, and without nesting them. The
following verifies that.
</p>
<p class="inwebparagraph">These rules are quite strict. It could be argued that nested brackets should be
allowed, allowing comments in text substitutions, but the result would be hard
to read and tricky for the user interface applications to syntax-colour.
</p>
<pre class="display">
<span class="reserved">int</span><span class="plain"> </span><span class="functiontext">Word::well_formed_text_routine</span><span class="plain">(</span><span class="identifier">wchar_t</span><span class="plain"> *</span><span class="identifier">fw</span><span class="plain">) {</span>
<span class="reserved">int</span><span class="plain"> </span><span class="identifier">i</span><span class="plain">, </span><span class="identifier">escaped</span><span class="plain"> = </span><span class="identifier">NOT_APPLICABLE</span><span class="plain">;</span>
<span class="reserved">for</span><span class="plain"> (</span><span class="identifier">i</span><span class="plain">=0; </span><span class="identifier">fw</span><span class="plain">[</span><span class="identifier">i</span><span class="plain">] != 0; </span><span class="identifier">i</span><span class="plain">++) {</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">fw</span><span class="plain">[</span><span class="identifier">i</span><span class="plain">] == </span><span class="constant">TEXT_SUBSTITUTION_BEGIN</span><span class="plain">) {</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">escaped</span><span class="plain"> == </span><span class="identifier">TRUE</span><span class="plain">) </span><span class="reserved">return</span><span class="plain"> </span><span class="identifier">FALSE</span><span class="plain">;</span>
<span class="identifier">escaped</span><span class="plain"> = </span><span class="identifier">TRUE</span><span class="plain">;</span>
<span class="plain">}</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">fw</span><span class="plain">[</span><span class="identifier">i</span><span class="plain">] == </span><span class="constant">TEXT_SUBSTITUTION_END</span><span class="plain">) {</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">escaped</span><span class="plain"> != </span><span class="identifier">TRUE</span><span class="plain">) </span><span class="reserved">return</span><span class="plain"> </span><span class="identifier">FALSE</span><span class="plain">;</span>
<span class="identifier">escaped</span><span class="plain"> = </span><span class="identifier">FALSE</span><span class="plain">;</span>
<span class="plain">}</span>
<span class="plain">}</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">escaped</span><span class="plain"> == </span><span class="identifier">NOT_APPLICABLE</span><span class="plain">) </span><span class="reserved">return</span><span class="plain"> </span><span class="identifier">escaped</span><span class="plain">;</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">escaped</span><span class="plain">) </span><span class="reserved">return</span><span class="plain"> </span><span class="identifier">FALSE</span><span class="plain">;</span>
<span class="reserved">return</span><span class="plain"> </span><span class="identifier">TRUE</span><span class="plain">;</span>
<span class="plain">}</span>
<span class="reserved">int</span><span class="plain"> </span><span class="functiontext">Word::perhaps_ill_formed_text_routine</span><span class="plain">(</span><span class="identifier">wchar_t</span><span class="plain"> *</span><span class="identifier">fw</span><span class="plain">) {</span>
<span class="reserved">int</span><span class="plain"> </span><span class="identifier">i</span><span class="plain">;</span>
<span class="reserved">for</span><span class="plain"> (</span><span class="identifier">i</span><span class="plain">=0; </span><span class="identifier">fw</span><span class="plain">[</span><span class="identifier">i</span><span class="plain">] != 0; </span><span class="identifier">i</span><span class="plain">++) {</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">fw</span><span class="plain">[</span><span class="identifier">i</span><span class="plain">] == </span><span class="constant">TEXT_SUBSTITUTION_BEGIN</span><span class="plain">) </span><span class="reserved">return</span><span class="plain"> </span><span class="identifier">TRUE</span><span class="plain">;</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">fw</span><span class="plain">[</span><span class="identifier">i</span><span class="plain">] == </span><span class="constant">TEXT_SUBSTITUTION_END</span><span class="plain">) </span><span class="reserved">return</span><span class="plain"> </span><span class="identifier">TRUE</span><span class="plain">;</span>
<span class="plain">}</span>
<span class="reserved">return</span><span class="plain"> </span><span class="identifier">FALSE</span><span class="plain">;</span>
<span class="plain">}</span>
</pre>
<p class="inwebparagraph"></p>
<p class="endnote">The function Word::well_formed_text_routine appears nowhere else.</p>
<p class="endnote">The function Word::perhaps_ill_formed_text_routine is used in 2/vcb (<a href="2-vcb.html#SP16">&#167;16</a>).</p>
<p class="inwebparagraph"><a id="SP4"></a><b>&#167;4. </b>Not to be done lightly: the output can be enormous.
</p>
<pre class="display">
<span class="reserved">void</span><span class="plain"> </span><span class="functiontext">Word::log_lexer_output</span><span class="plain">(</span><span class="reserved">void</span><span class="plain">) {</span>
<span class="identifier">LOG</span><span class="plain">(</span><span class="string">"Entire lexer output to date:\</span><span class="plain">n</span><span class="string">"</span><span class="plain">);</span>
<span class="reserved">for</span><span class="plain"> (</span><span class="reserved">int</span><span class="plain"> </span><span class="identifier">i</span><span class="plain">=0; </span><span class="identifier">i</span><span class="plain">&lt;</span><span class="identifier">lexer_wordcount</span><span class="plain">; </span><span class="identifier">i</span><span class="plain">++)</span>
<span class="identifier">LOG</span><span class="plain">(</span><span class="string">"%d: &lt;%+N&gt; &lt;%N&gt; &lt;%02x&gt;\</span><span class="plain">n</span><span class="string">"</span><span class="plain">, </span><span class="identifier">i</span><span class="plain">, </span><span class="identifier">i</span><span class="plain">, </span><span class="identifier">i</span><span class="plain">, </span><span class="functiontext">Lexer::break_before</span><span class="plain">(</span><span class="identifier">i</span><span class="plain">));</span>
<span class="identifier">LOG</span><span class="plain">(</span><span class="string">"------\</span><span class="plain">n</span><span class="string">"</span><span class="plain">);</span>
<span class="plain">}</span>
</pre>
<p class="inwebparagraph"></p>
<p class="endnote">The function Word::log_lexer_output appears nowhere else.</p>
<p class="inwebparagraph"><a id="SP5"></a><b>&#167;5. Casing and sentence division. </b>Casing is only sometimes informative in English: for the first word in
a sentence, we expect to find an upper-case letter, so that there is no
easy way to tell the name of a person or institution from a common noun.
But in other cases an upper case initial letter is unexpected, and can
tell us something.
</p>
<pre class="display">
<span class="reserved">int</span><span class="plain"> </span><span class="functiontext">Word::unexpectedly_upper_case</span><span class="plain">(</span><span class="reserved">int</span><span class="plain"> </span><span class="identifier">wn</span><span class="plain">) {</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">wn</span><span class="plain">&lt;1) </span><span class="reserved">return</span><span class="plain"> </span><span class="identifier">FALSE</span><span class="plain">;</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">compare_word</span><span class="plain">(</span><span class="identifier">wn</span><span class="plain">-1, </span><span class="identifier">FULLSTOP_V</span><span class="plain">)) </span><span class="reserved">return</span><span class="plain"> </span><span class="identifier">FALSE</span><span class="plain">;</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">compare_word</span><span class="plain">(</span><span class="identifier">wn</span><span class="plain">-1, </span><span class="identifier">PARBREAK_V</span><span class="plain">)) </span><span class="reserved">return</span><span class="plain"> </span><span class="identifier">FALSE</span><span class="plain">;</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">compare_word</span><span class="plain">(</span><span class="identifier">wn</span><span class="plain">-1, </span><span class="identifier">COLON_V</span><span class="plain">)) </span><span class="reserved">return</span><span class="plain"> </span><span class="identifier">FALSE</span><span class="plain">;</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">isupper</span><span class="plain">(*(</span><span class="functiontext">Lexer::word_raw_text</span><span class="plain">(</span><span class="identifier">wn</span><span class="plain">)))) {</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="functiontext">Word::text_ending_sentence</span><span class="plain">(</span><span class="identifier">wn</span><span class="plain">-1)) </span><span class="reserved">return</span><span class="plain"> </span><span class="identifier">FALSE</span><span class="plain">;</span>
<span class="reserved">return</span><span class="plain"> </span><span class="identifier">TRUE</span><span class="plain">;</span>
<span class="plain">}</span>
<span class="reserved">return</span><span class="plain"> </span><span class="identifier">FALSE</span><span class="plain">;</span>
<span class="plain">}</span>
</pre>
<p class="inwebparagraph"></p>
<p class="endnote">The function Word::unexpectedly_upper_case is used in 2/wa (<a href="2-wa.html#SP11">&#167;11</a>), 4/prf (<a href="4-prf.html#SP53">&#167;53</a>), 4/bn (<a href="4-bn.html#SP2">&#167;2</a>).</p>
<p class="inwebparagraph"><a id="SP6"></a><b>&#167;6. </b>Is the word at <code class="display"><span class="extract">wn</span></code> in single quotes? Count the number at the ends.
</p>
<pre class="display">
<span class="reserved">int</span><span class="plain"> </span><span class="functiontext">Word::singly_quoted</span><span class="plain">(</span><span class="reserved">int</span><span class="plain"> </span><span class="identifier">wn</span><span class="plain">) {</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">wn</span><span class="plain">&lt;1) </span><span class="reserved">return</span><span class="plain"> </span><span class="identifier">FALSE</span><span class="plain">;</span>
<span class="identifier">wchar_t</span><span class="plain"> *</span><span class="identifier">p</span><span class="plain"> = </span><span class="functiontext">Lexer::word_raw_text</span><span class="plain">(</span><span class="identifier">wn</span><span class="plain">);</span>
<span class="reserved">int</span><span class="plain"> </span><span class="identifier">qc</span><span class="plain"> = 0;</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">p</span><span class="plain">[0] == </span><span class="character">'\</span><span class="plain">'</span><span class="character">'</span><span class="plain">) </span><span class="identifier">qc</span><span class="plain">++;</span>
<span class="reserved">if</span><span class="plain"> ((</span><span class="identifier">Wide::len</span><span class="plain">(</span><span class="identifier">p</span><span class="plain">) &gt; 1) &amp;&amp; (</span><span class="identifier">p</span><span class="plain">[</span><span class="identifier">Wide::len</span><span class="plain">(</span><span class="identifier">p</span><span class="plain">)-1] == </span><span class="character">'\</span><span class="plain">'</span><span class="character">'</span><span class="plain">)) </span><span class="identifier">qc</span><span class="plain">++;</span>
<span class="reserved">return</span><span class="plain"> </span><span class="identifier">qc</span><span class="plain">;</span>
<span class="plain">}</span>
</pre>
<p class="inwebparagraph"></p>
<p class="endnote">The function Word::singly_quoted appears nowhere else.</p>
<p class="inwebparagraph"><a id="SP7"></a><b>&#167;7. </b>Does the word at <code class="display"><span class="extract">wn</span></code> appear to be a piece of quoted text which, because
it ends with punctuation, may also end the sentence which quotes it?
</p>
<pre class="display">
<span class="reserved">int</span><span class="plain"> </span><span class="functiontext">Word::text_ending_sentence</span><span class="plain">(</span><span class="reserved">int</span><span class="plain"> </span><span class="identifier">wn</span><span class="plain">) {</span>
<span class="identifier">wchar_t</span><span class="plain"> *</span><span class="identifier">p</span><span class="plain"> = </span><span class="functiontext">Lexer::word_raw_text</span><span class="plain">(</span><span class="identifier">wn</span><span class="plain">);</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">p</span><span class="plain">[0] != </span><span class="character">'"'</span><span class="plain">) </span><span class="reserved">return</span><span class="plain"> </span><span class="identifier">FALSE</span><span class="plain">;</span>
<span class="identifier">p</span><span class="plain"> += </span><span class="identifier">Wide::len</span><span class="plain">(</span><span class="identifier">p</span><span class="plain">) - 2;</span>
<span class="reserved">if</span><span class="plain"> ((</span><span class="identifier">p</span><span class="plain">[0] == </span><span class="character">'.'</span><span class="plain">) &amp;&amp; (</span><span class="identifier">p</span><span class="plain">[1] == </span><span class="character">'"'</span><span class="plain">)) </span><span class="reserved">return</span><span class="plain"> </span><span class="identifier">TRUE</span><span class="plain">;</span>
<span class="reserved">if</span><span class="plain"> ((</span><span class="identifier">p</span><span class="plain">[0] == </span><span class="character">'?'</span><span class="plain">) &amp;&amp; (</span><span class="identifier">p</span><span class="plain">[1] == </span><span class="character">'"'</span><span class="plain">)) </span><span class="reserved">return</span><span class="plain"> </span><span class="identifier">TRUE</span><span class="plain">;</span>
<span class="reserved">if</span><span class="plain"> ((</span><span class="identifier">p</span><span class="plain">[0] == </span><span class="character">'!'</span><span class="plain">) &amp;&amp; (</span><span class="identifier">p</span><span class="plain">[1] == </span><span class="character">'"'</span><span class="plain">)) </span><span class="reserved">return</span><span class="plain"> </span><span class="identifier">TRUE</span><span class="plain">;</span>
<span class="identifier">p</span><span class="plain">--;</span>
<span class="reserved">if</span><span class="plain"> ((</span><span class="identifier">p</span><span class="plain">[0] == </span><span class="character">'.'</span><span class="plain">) &amp;&amp; (</span><span class="identifier">p</span><span class="plain">[1] == </span><span class="character">')'</span><span class="plain">) &amp;&amp; (</span><span class="identifier">p</span><span class="plain">[2] == </span><span class="character">'"'</span><span class="plain">)) </span><span class="reserved">return</span><span class="plain"> </span><span class="identifier">TRUE</span><span class="plain">;</span>
<span class="reserved">if</span><span class="plain"> ((</span><span class="identifier">p</span><span class="plain">[0] == </span><span class="character">'?'</span><span class="plain">) &amp;&amp; (</span><span class="identifier">p</span><span class="plain">[1] == </span><span class="character">')'</span><span class="plain">) &amp;&amp; (</span><span class="identifier">p</span><span class="plain">[2] == </span><span class="character">'"'</span><span class="plain">)) </span><span class="reserved">return</span><span class="plain"> </span><span class="identifier">TRUE</span><span class="plain">;</span>
<span class="reserved">if</span><span class="plain"> ((</span><span class="identifier">p</span><span class="plain">[0] == </span><span class="character">'!'</span><span class="plain">) &amp;&amp; (</span><span class="identifier">p</span><span class="plain">[1] == </span><span class="character">')'</span><span class="plain">) &amp;&amp; (</span><span class="identifier">p</span><span class="plain">[2] == </span><span class="character">'"'</span><span class="plain">)) </span><span class="reserved">return</span><span class="plain"> </span><span class="identifier">TRUE</span><span class="plain">;</span>
<span class="reserved">if</span><span class="plain"> ((</span><span class="identifier">p</span><span class="plain">[0] == </span><span class="character">'.'</span><span class="plain">) &amp;&amp; (</span><span class="identifier">p</span><span class="plain">[1] == </span><span class="character">'\</span><span class="plain">'</span><span class="character">'</span><span class="plain">) &amp;&amp; (</span><span class="identifier">p</span><span class="plain">[2] == </span><span class="character">'"'</span><span class="plain">)) </span><span class="reserved">return</span><span class="plain"> </span><span class="identifier">TRUE</span><span class="plain">;</span>
<span class="reserved">if</span><span class="plain"> ((</span><span class="identifier">p</span><span class="plain">[0] == </span><span class="character">'?'</span><span class="plain">) &amp;&amp; (</span><span class="identifier">p</span><span class="plain">[1] == </span><span class="character">'\</span><span class="plain">'</span><span class="character">'</span><span class="plain">) &amp;&amp; (</span><span class="identifier">p</span><span class="plain">[2] == </span><span class="character">'"'</span><span class="plain">)) </span><span class="reserved">return</span><span class="plain"> </span><span class="identifier">TRUE</span><span class="plain">;</span>
<span class="reserved">if</span><span class="plain"> ((</span><span class="identifier">p</span><span class="plain">[0] == </span><span class="character">'!'</span><span class="plain">) &amp;&amp; (</span><span class="identifier">p</span><span class="plain">[1] == </span><span class="character">'\</span><span class="plain">'</span><span class="character">'</span><span class="plain">) &amp;&amp; (</span><span class="identifier">p</span><span class="plain">[2] == </span><span class="character">'"'</span><span class="plain">)) </span><span class="reserved">return</span><span class="plain"> </span><span class="identifier">TRUE</span><span class="plain">;</span>
<span class="reserved">return</span><span class="plain"> </span><span class="identifier">FALSE</span><span class="plain">;</span>
<span class="plain">}</span>
</pre>
<p class="inwebparagraph"></p>
<p class="endnote">The function Word::text_ending_sentence is used in <a href="#SP5">&#167;5</a>.</p>
<p class="inwebparagraph"><a id="SP8"></a><b>&#167;8. Dequoting literal text. </b>A utility for stripping double-quotes from literal text, along with
initial or trailing spaces inside those quotes.
</p>
<pre class="display">
<span class="reserved">void</span><span class="plain"> </span><span class="functiontext">Word::dequote</span><span class="plain">(</span><span class="reserved">int</span><span class="plain"> </span><span class="identifier">wn</span><span class="plain">) {</span>
<span class="identifier">wchar_t</span><span class="plain"> *</span><span class="identifier">previous_text</span><span class="plain"> = </span><span class="functiontext">Lexer::word_text</span><span class="plain">(</span><span class="identifier">wn</span><span class="plain">);</span>
<span class="identifier">wchar_t</span><span class="plain"> *</span><span class="identifier">dequoted_text</span><span class="plain">;</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">previous_text</span><span class="plain">[0] != </span><span class="character">'"'</span><span class="plain">) </span><span class="reserved">return</span><span class="plain">;</span>
<span class="functiontext">Lexer::set_word_raw_text</span><span class="plain">(</span><span class="identifier">wn</span><span class="plain">, </span><span class="functiontext">Lexer::copy_to_memory</span><span class="plain">(</span><span class="functiontext">Lexer::word_raw_text</span><span class="plain">(</span><span class="identifier">wn</span><span class="plain">)));</span>
<span class="identifier">dequoted_text</span><span class="plain"> = </span><span class="identifier">previous_text</span><span class="plain"> + 1;</span>
<span class="reserved">while</span><span class="plain"> (*(</span><span class="identifier">dequoted_text</span><span class="plain">) == </span><span class="character">' '</span><span class="plain">) </span><span class="identifier">dequoted_text</span><span class="plain">++;</span>
<span class="reserved">if</span><span class="plain"> ((</span><span class="identifier">Wide::len</span><span class="plain">(</span><span class="identifier">dequoted_text</span><span class="plain">) &gt; 0) &amp;&amp;</span>
<span class="plain">(*(</span><span class="identifier">dequoted_text</span><span class="plain">+</span><span class="identifier">Wide::len</span><span class="plain">(</span><span class="identifier">dequoted_text</span><span class="plain">)-1) == </span><span class="character">'"'</span><span class="plain">))</span>
<span class="plain">*(</span><span class="identifier">dequoted_text</span><span class="plain">+</span><span class="identifier">Wide::len</span><span class="plain">(</span><span class="identifier">dequoted_text</span><span class="plain">)-1) = 0;</span>
<span class="reserved">while</span><span class="plain"> ((</span><span class="identifier">Wide::len</span><span class="plain">(</span><span class="identifier">dequoted_text</span><span class="plain">) &gt; 0) &amp;&amp;</span>
<span class="plain">(*(</span><span class="identifier">dequoted_text</span><span class="plain">+</span><span class="identifier">Wide::len</span><span class="plain">(</span><span class="identifier">dequoted_text</span><span class="plain">)-1) == </span><span class="character">' '</span><span class="plain">))</span>
<span class="plain">*(</span><span class="identifier">dequoted_text</span><span class="plain">+</span><span class="identifier">Wide::len</span><span class="plain">(</span><span class="identifier">dequoted_text</span><span class="plain">)-1) = 0;</span>
<span class="functiontext">Lexer::set_word_text</span><span class="plain">(</span><span class="identifier">wn</span><span class="plain">, </span><span class="identifier">dequoted_text</span><span class="plain">);</span>
<span class="identifier">LOGIF</span><span class="plain">(</span><span class="identifier">VOCABULARY</span><span class="plain">, </span><span class="string">"Dequoting word %d &lt;%w&gt; to &lt;%w&gt;\</span><span class="plain">n</span><span class="string">"</span><span class="plain">,</span>
<span class="identifier">wn</span><span class="plain">, </span><span class="identifier">previous_text</span><span class="plain">, </span><span class="identifier">dequoted_text</span><span class="plain">);</span>
<span class="functiontext">Vocabulary::identify_word</span><span class="plain">(</span><span class="identifier">wn</span><span class="plain">);</span>
<span class="functiontext">Vocabulary::set_raw_exemplar_to_text</span><span class="plain">(</span><span class="identifier">wn</span><span class="plain">);</span>
<span class="plain">}</span>
</pre>
<p class="inwebparagraph"></p>
<p class="endnote">The function Word::dequote appears nowhere else.</p>
<p class="inwebparagraph"><a id="SP9"></a><b>&#167;9. Dictionary words. </b>We take a wide Unicode string and compile an I6 dictionary word constant
to lodge the same text into the virtual machine's parsing dictionary.
</p>
<p class="inwebparagraph">A legal I6 dictionary word can take several forms: it can be in single
quotes, <code class="display"><span class="extract">'thus'</span></code>, but only if it is more than one character long, since
<code class="display"><span class="extract">'t'</span></code> would be the character value of lower-case T instead. (Or it can be
double-quoted <code class="display"><span class="extract">"so"</span></code>, but only in grammar or properties; this usage is
deprecated and we avoid it.) Within the dictionary word, <code class="display"><span class="extract">^</span></code> is an escape
character meaning a literal single quote, and the notation <code class="display"><span class="extract">@{xx}</span></code> is an
escape meaning the character with hexadecimal value <code class="display"><span class="extract">xx</span></code>.
</p>
<p class="inwebparagraph">Optionally, a dictionary word can end with a pair of slashes and then,
optionally again, markers to indicate that the word is (for instance) a
plural: thus <code class="display"><span class="extract">'newts//p'</span></code>. Using no markers, as in <code class="display"><span class="extract">'toads//'</span></code>, makes a
word equivalent to that without a marker, but avoids the single-letter
problem &mdash; so the preferred modern way to write a single-character I6
dictionary word is <code class="display"><span class="extract">'t//'</span></code>, and this is what the following routine does.
(Note the exceptional case where the word consists only of a <code class="display"><span class="extract">'/'</span></code>: here
we cannot write <code class="display"><span class="extract">'///'</span></code> because I6 reads this as <code class="display"><span class="extract">//</span></code> plus an invalid
marker <code class="display"><span class="extract">/</span></code>, and throws an error. We escape the single <code class="display"><span class="extract">/</span></code> to avoid this.
In all other cases there's no need to escape a <code class="display"><span class="extract">/</span></code>.)
</p>
<p class="inwebparagraph">Dictionary words with a literal <code class="display"><span class="extract">~</span></code> in are, as it happens, not parsable
by the Z-machine, but the code below &mdash; employing the <code class="display"><span class="extract">@{7E}</span></code>
escape &mdash; is in principle legal, and it does work on Glulx.
</p>
<p class="inwebparagraph">Very long words can safely be truncated since the virtual machines do not
have indefinitely long dictionary resolution anyway, and we had better do
so because I6 rejects overlong text between single quotation marks.
</p>
<pre class="display">
<span class="reserved">void</span><span class="plain"> </span><span class="functiontext">Word::compile_to_I6_dictionary</span><span class="plain">(</span><span class="identifier">OUTPUT_STREAM</span><span class="plain">, </span><span class="identifier">wchar_t</span><span class="plain"> *</span><span class="identifier">p</span><span class="plain">, </span><span class="reserved">int</span><span class="plain"> </span><span class="identifier">pluralise</span><span class="plain">) {</span>
<span class="reserved">int</span><span class="plain"> </span><span class="identifier">c</span><span class="plain">, </span><span class="identifier">n</span><span class="plain"> = 0;</span>
<span class="identifier">WRITE</span><span class="plain">(</span><span class="string">"'"</span><span class="plain">);</span>
<span class="reserved">for</span><span class="plain"> (</span><span class="identifier">c</span><span class="plain">=0; </span><span class="identifier">p</span><span class="plain">[</span><span class="identifier">c</span><span class="plain">] != 0; </span><span class="identifier">c</span><span class="plain">++) {</span>
<span class="reserved">switch</span><span class="plain">(</span><span class="identifier">p</span><span class="plain">[</span><span class="identifier">c</span><span class="plain">]) {</span>
<span class="reserved">case</span><span class="plain"> </span><span class="character">'/'</span><span class="plain">: </span><span class="reserved">if</span><span class="plain"> (</span><span class="identifier">p</span><span class="plain">[1] == 0) </span><span class="identifier">WRITE</span><span class="plain">(</span><span class="string">"@{2F}"</span><span class="plain">); </span><span class="reserved">else</span><span class="plain"> </span><span class="identifier">WRITE</span><span class="plain">(</span><span class="string">"/"</span><span class="plain">); </span><span class="reserved">break</span><span class="plain">;</span>
<span class="reserved">case</span><span class="plain"> </span><span class="character">'\</span><span class="plain">'</span><span class="character">'</span><span class="plain">: </span><span class="identifier">WRITE</span><span class="plain">(</span><span class="string">"^"</span><span class="plain">); </span><span class="reserved">break</span><span class="plain">;</span>
<span class="reserved">case</span><span class="plain"> </span><span class="character">'^'</span><span class="plain">: </span><span class="identifier">WRITE</span><span class="plain">(</span><span class="string">"@{5E}"</span><span class="plain">); </span><span class="reserved">break</span><span class="plain">;</span>
<span class="reserved">case</span><span class="plain"> </span><span class="character">'~'</span><span class="plain">: </span><span class="identifier">WRITE</span><span class="plain">(</span><span class="string">"@{7E}"</span><span class="plain">); </span><span class="reserved">break</span><span class="plain">;</span>
<span class="reserved">case</span><span class="plain"> </span><span class="character">'@'</span><span class="plain">: </span><span class="identifier">WRITE</span><span class="plain">(</span><span class="string">"@{40}"</span><span class="plain">); </span><span class="reserved">break</span><span class="plain">;</span>
<span class="reserved">default</span><span class="plain">: </span><span class="identifier">PUT</span><span class="plain">(</span><span class="identifier">p</span><span class="plain">[</span><span class="identifier">c</span><span class="plain">]);</span>
<span class="plain">}</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">n</span><span class="plain">++ &gt; 32) </span><span class="reserved">break</span><span class="plain">;</span>
<span class="plain">}</span>
<span class="reserved">if</span><span class="plain"> (</span><span class="identifier">pluralise</span><span class="plain">) </span><span class="identifier">WRITE</span><span class="plain">(</span><span class="string">"//p"</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">Wide::len</span><span class="plain">(</span><span class="identifier">p</span><span class="plain">) == 1) </span><span class="identifier">WRITE</span><span class="plain">(</span><span class="string">"//"</span><span class="plain">);</span>
<span class="identifier">WRITE</span><span class="plain">(</span><span class="string">"'"</span><span class="plain">);</span>
<span class="plain">}</span>
</pre>
<p class="inwebparagraph"></p>
<p class="endnote">The function Word::compile_to_I6_dictionary is used in 3/lxr (<a href="3-lxr.html#SP18">&#167;18</a>).</p>
<hr class="tocbar">
<ul class="toc"><li><i>(This section begins Chapter 4: Parsing.)</i></li><li><a href="4-prf.html">Continue with 'Preform'</a></li></ul><hr class="tocbar">
<!--End of weave-->
</body>
</html>
Reference in a new issue View git blame Copy permalink