Patch to add rudimentary custom entity capability

Greetings.

I was using tidy to process an XML file that used some custom entities.
Since tidy wasn't aware of those entities, it refused to generate a
tidied file. I did a little rooting around and modified the code just
enough to produce the desired effect. There are some TODO comments in
the code to point out where it is suboptimal. Nonetheless, I'm posting
it here in case anyone else wants to make use of it or in case someone
wants to tidy (ahem) it up for inclusion in the next release.

Enjoy.

-- Gregor N. Purdy
gregor@focusresearch.com
http://www.focusresearch.com/gregor/

diff -Naur tidy4aug00/Overview.html tidy4aug00-gnp/Overview.html
--- tidy4aug00/Overview.html	Fri Aug  4 12:21:05 2000
+++ tidy4aug00-gnp/Overview.html	Tue Nov 28 15:11:34 2000
@@ -422,6 +422,13 @@
 this feature is to allow Tidy to be applied to Cold Fusion
 files.</p>
 
+<p>You can also teach Tidy about new entities by declaring them
+in the configuration file, the syntax is:</p>
+
+<pre>
+  new-entities: <em>entity1, entity2, entity3</em>
+</pre>
+
 <p class="c7">I am working on ways to make it easy to customize
 the permitted document syntax using <a
 href="http://www.w3.org/People/Raggett/dtdgen/Docs/">assertion
@@ -1053,6 +1060,14 @@
 "slide1.html", "slide2.html" etc. The default is
 <em>no</em>.</dd>
 
+<dt>new-entities: <em>entity1, entity2, entity3</em></dt>
+
+<dd>Use this to declare new entities. The option takes a space
+or comma separated list of entity names. There is no mechanism
+for specifying the values of the entities. Note that tidy still
+does not read custom entities from any internal document subset.
+</dd>
+
 <dt>new-empty-tags: <em>tag1, tag2, tag3</em></dt>
 
 <dd>Use this to declare new empty inline tags. The option takes a
@@ -1115,6 +1130,7 @@
   mprescripts, mtable, mtr, mtd, mth
 new-blocklevel-tags: cfoutput, cfquery
 new-empty-tags: cfelse
+new-entities: dollar
 </pre>
 
 <h3><a id="scripts" name="scripts">Using Tidy from
diff -Naur tidy4aug00/config.c tidy4aug00-gnp/config.c
--- tidy4aug00/config.c	Fri Aug  4 12:21:05 2000
+++ tidy4aug00-gnp/config.c	Tue Nov 28 15:00:51 2000
@@ -104,6 +104,7 @@
 static char *inline_tags;
 static char *block_tags;
 static char *empty_tags;
+static char *entities;
 static char *pre_tags;
 
 
@@ -182,6 +183,7 @@
     {"new-blocklevel-tags", {(int *)&block_tags},   ParseTagNames},
     {"new-empty-tags",  {(int *)&empty_tags},       ParseTagNames},
     {"new-pre-tags",    {(int *)&pre_tags},         ParseTagNames},
+    {"new-entities",    {(int *)&entities},         ParseTagNames}, /* TODO: Really should get name+value */
     {"char-encoding",   {(int *)&CharEncoding},     ParseCharEncoding},
     {"doctype",         {(int *)&doctype_str},      ParseDocType},
     {"fix-backslash",   {(int *)&FixBackslash},     ParseBool},
@@ -663,6 +665,8 @@
             DefineBlockTag(buf);
         else if (location.string == &empty_tags)
             DefineEmptyTag(buf);
+        else if (location.string == &entities)
+            DefineEntity(buf, ""); /* TODO: Really should get its value and pass it in */
         else if (location.string == &pre_tags)
             DefinePreTag(buf);
 
diff -Naur tidy4aug00/entities.c tidy4aug00-gnp/entities.c
--- tidy4aug00/entities.c	Fri Aug  4 12:21:05 2000
+++ tidy4aug00-gnp/entities.c	Tue Nov 28 15:01:43 2000
@@ -357,6 +357,37 @@
         install(ep->name, ep->code);
 }
 
+void DefineEntity(char * name, char * value)
+{
+	int code;
+	int l;
+
+	l = strlen(value);
+
+	if (l == 0)
+	{
+		code = ' '; /* TODO: This is a bad hack to allow entities to be defined without values */
+	}
+	else if (l == 1)
+	{
+		code = value[0];
+	}
+	else
+	{
+		/* TODO: We really should handle general entities */
+		if (value[0] != '&') return;
+
+		/* TODO: We really should handle general entities */
+		if (value[1] != '#') return;
+
+		code = EntityCode(value);
+
+		if (code == 0) return;
+	}
+
+	install(name, code);
+}
+
 void FreeEntities(void)
 {
     struct nlist *prev, *next;
diff -Naur tidy4aug00/release-notes.html tidy4aug00-gnp/release-notes.html
--- tidy4aug00/release-notes.html	Fri Aug  4 12:21:05 2000
+++ tidy4aug00-gnp/release-notes.html	Tue Nov 28 15:07:27 2000
@@ -73,6 +73,13 @@
 current workload means that I don't get much time left to work on
 HTML Tidy.</p>
 
+<h2>November 2000</h2>
+
+<p>Gregor N. Purdy &lt;gregor@focusresearch.com&gt made a quick
+hack to permit the definition of custom entities in the config
+file via the new-entities option. This is handy for tidying
+XML files.</p>
+
 <h2>August 2000</h2>
 
 <p>Ann Navarro comments that the "appears to" message is