kc3-lang/md4c

diff --git a/test/spec.txt b/test/spec.txt
index 2f01257..0bbd360 100644
--- a/test/spec.txt
+++ b/test/spec.txt
@@ -328,8 +328,10 @@ that is not a [whitespace character].
 
 An [ASCII punctuation character](@)
 is `!`, `"`, `#`, `$`, `%`, `&`, `'`, `(`, `)`,
-`*`, `+`, `,`, `-`, `.`, `/`, `:`, `;`, `<`, `=`, `>`, `?`, `@`,
-`[`, `\`, `]`, `^`, `_`, `` ` ``, `{`, `|`, `}`, or `~`.
+`*`, `+`, `,`, `-`, `.`, `/` (U+0021–2F), 
+`:`, `;`, `<`, `=`, `>`, `?`, `@` (U+003A–0040),
+`[`, `\`, `]`, `^`, `_`, `` ` `` (U+005B–0060), 
+`{`, `|`, `}`, or `~` (U+007B–007E).
 
 A [punctuation character](@) is an [ASCII
 punctuation character] or anything in
@@ -1922,9 +1924,11 @@ bar
 
 
 An [info string] can be provided after the opening code fence.
-Opening and closing spaces will be stripped, and the first word, prefixed
-with `language-`, is used as the value for the `class` attribute of the
-`code` element within the enclosing `pre` element.
+Although this spec doesn't mandate any particular treatment of
+the info string, the first word is typically used to specify
+the language of the code block. In HTML output, the language is
+normally indicated by adding a class to the `code` element consisting
+of `language-` followed by the language name.
 
 ```````````````````````````````` example
 ```ruby
@@ -2003,15 +2007,15 @@ Closing code fences cannot have [info strings]:
 An [HTML block](@) is a group of lines that is treated
 as raw HTML (and will not be escaped in HTML output).
 
-There are seven kinds of [HTML block], which can be defined
-by their start and end conditions.  The block begins with a line that
-meets a [start condition](@) (after up to three spaces
-optional indentation).  It ends with the first subsequent line that
-meets a matching [end condition](@), or the last line of
-the document or other [container block](#container-blocks)), if no
-line is encountered that meets the [end condition].  If the first line
-meets both the [start condition] and the [end condition], the block
-will contain just that line.
+There are seven kinds of [HTML block], which can be defined by their
+start and end conditions.  The block begins with a line that meets a
+[start condition](@) (after up to three spaces optional indentation).
+It ends with the first subsequent line that meets a matching [end
+condition](@), or the last line of the document, or the last line of
+the [container block](#container-blocks) containing the current HTML
+block, if no line is encountered that meets the [end condition].  If
+the first line meets both the [start condition] and the [end
+condition], the block will contain just that line.
 
 1.  **Start condition:**  line begins with the string `<script`,
 `<pre`, or `<style` (case-insensitive), followed by whitespace,
@@ -2050,9 +2054,9 @@ the string `/>`.\
 **End condition:** line is followed by a [blank line].
 
 7.  **Start condition:**  line begins with a complete [open tag]
-or [closing tag] (with any [tag name] other than `script`,
-`style`, or `pre`) followed only by [whitespace]
-or the end of the line.\
+(with any [tag name] other than `script`,
+`style`, or `pre`) or a complete [closing tag],
+followed only by [whitespace] or the end of the line.\
 **End condition:** line is followed by a [blank line].
 
 HTML blocks continue until they are closed by their appropriate
@@ -6107,7 +6111,8 @@ The following rules define emphasis and strong emphasis:
     [delimiter runs].  If one of the delimiters can both
     open and close emphasis, then the sum of the lengths of the
     delimiter runs containing the opening and closing delimiters
-    must not be a multiple of 3.
+    must not be a multiple of 3 unless both lengths are
+    multiples of 3.
 
 10. Strong emphasis begins with a delimiter that
     [can open strong emphasis] and ends with a delimiter that
@@ -6117,7 +6122,8 @@ The following rules define emphasis and strong emphasis:
     [delimiter runs].  If one of the delimiters can both open
     and close strong emphasis, then the sum of the lengths of
     the delimiter runs containing the opening and closing
-    delimiters must not be a multiple of 3.
+    delimiters must not be a multiple of 3 unless both lengths
+    are multiples of 3.
 
 11. A literal `*` character cannot occur at the beginning or end of
     `*`-delimited emphasis or `**`-delimited strong emphasis, unless it
@@ -6736,7 +6742,8 @@ is precluded by the condition that a delimiter that
 can both open and close (like the `*` after `foo`)
 cannot form emphasis if the sum of the lengths of
 the delimiter runs containing the opening and
-closing delimiters is a multiple of 3.
+closing delimiters is a multiple of 3 unless
+both lengths are multiples of 3.
 
 
 For the same reason, we don't get two consecutive
@@ -6776,6 +6783,23 @@ omitted:
 ````````````````````````````````
 
 
+When the lengths of the interior closing and opening
+delimiter runs are *both* multiples of 3, though,
+they can match to create emphasis:
+
+```````````````````````````````` example
+foo***bar***baz
+.
+<p>foo<em><strong>bar</strong></em>baz</p>
+````````````````````````````````
+
+```````````````````````````````` example
+foo******bar*********baz
+.
+<p>foo<strong><strong><strong>bar</strong></strong></strong>***baz</p>
+````````````````````````````````
+
+
 Indefinite levels of nesting are possible:
 
 ```````````````````````````````` example
@@ -7314,12 +7338,13 @@ A [link destination](@) consists of either
   closing `>` that contains no line breaks or unescaped
   `<` or `>` characters, or
 
-- a nonempty sequence of characters that does not include
-  ASCII space or control characters, and includes parentheses
-  only if (a) they are backslash-escaped or (b) they are part of
-  a balanced pair of unescaped parentheses.  (Implementations
-  may impose limits on parentheses nesting to avoid performance
-  issues, but at least three levels of nesting should be supported.)
+- a nonempty sequence of characters that does not start with
+  `<`, does not include ASCII space or control characters, and
+  includes parentheses only if (a) they are backslash-escaped or
+  (b) they are part of a balanced pair of unescaped parentheses.
+  (Implementations may impose limits on parentheses nesting to
+  avoid performance issues, but at least three levels of nesting
+  should be supported.)
 
 A [link title](@)  consists of either
 
@@ -7332,7 +7357,8 @@ A [link title](@)  consists of either
   backslash-escaped, or
 
 - a sequence of zero or more characters between matching parentheses
-  (`(...)`), including a `)` character only if it is backslash-escaped.
+  (`(...)`), including a `(` or `)` character only if it is
+  backslash-escaped.
 
 Although [link titles] may span multiple lines, they may not contain
 a [blank line].
@@ -7416,6 +7442,15 @@ bar>)
 bar>)</p>
 ````````````````````````````````
 
+Pointy brackets that enclose links must be unescaped:
+
+```````````````````````````````` example
+[link](<foo\>)
+.
+<p><a href="%3Cfoo%3E">link</a></p>
+````````````````````````````````
+
+
 Parentheses inside the link destination may be escaped:
 
 ```````````````````````````````` example
@@ -9481,7 +9516,8 @@ just above `stack_bottom` (or the first element if `stack_bottom`
 is NULL).
 
 We keep track of the `openers_bottom` for each delimiter
-type (`*`, `_`).  Initialize this to `stack_bottom`.
+type (`*`, `_`) and each length of the closing delimiter run
+(modulo 3).  Initialize this to `stack_bottom`.
 
 Then we repeat the following until we run out of potential
 closers:
@@ -9513,7 +9549,7 @@ closers:
     of the delimiter stack.  If the closing node is removed, reset
     `current_position` to the next element in the stack.
 
-- If none in found:
+- If none is found:
 
   + Set `openers_bottom` to the element before `current_position`.
     (We know that there are no openers for this kind of closer up to and