Added new rule for enhanced markdown ordered lists: if the list marker

is a capital letter followed by a period (including a single-letter
capital roman numeral), then it must be followed by at least two spaces.
The point of this is to avoid accidentally treating people's initials as
list markers: a paragraph may begin:

    B. Russell was an English philosopher.

and this shouldn't be treated as a list.

Modified Markdown reader and README documentation.
Added a test case.


git-svn-id: https://pandoc.googlecode.com/svn/trunk@880 788f1e2b-df1e-0410-8736-df70ead52e1b

README

@@ -452,11 +452,31 @@ Unlike standard markdown, Pandoc allows ordered list items to be marked
 with uppercase and lowercase letters and roman numerals, in addition to
 arabic numerals. (This behavior can be turned off using the `--strict`
 option.) List markers may be enclosed in parentheses or followed by a
-single right-parentheses or period. Pandoc also pays attention to the
-type of list marker used, and to the starting number, and both of these
-are preserved where possible in the output format. Thus, the following
-yields a list with numbers followed by a single parenthesis, starting
-with 9, and a sublist with lowercase roman numerals:
+single right-parentheses or period. They must be separated from the
+text that follows by at least one space, and, if the list marker is a
+capital letter with a period, by at least two spaces.[^2]
+
+[^2]:  The point of this rule is to ensure that normal paragraphs
+    starting with people's initials, like
+
+        B. Russell was an English philosopher.
+
+    do not get treated as list items.
+
+    This rule will not prevent
+
+        (C) 2007 Joe Smith
+
+    from being interpreted as a list item.  In this case, a backslash
+    escape can be used:
+
+        (C\) 2007 Joe Smith
+    
+Pandoc also pays attention to the type of list marker used, and to the
+starting number, and both of these are preserved where possible in the
+output format. Thus, the following yields a list with numbers followed
+by a single parenthesis, starting with 9, and a sublist with lowercase
+roman numerals:
 
      9)  Ninth
     10)  Tenth
@@ -491,27 +511,10 @@ gets treated as if it were
 
     1.  One
     2.  Two
-        A. Sub
-        B. Sub
+        A.  Sub
+        B.  Sub
     3.  Three
 
-Note that a list beginning with a single letter will be interpreted as
-an alphabetic list. So you are out of luck if you want a roman-numbered
-list starting with 100 (C).
-
-Note also that a paragraph starting with a capital letter and a period
-(for example, an initial) or a capital letter in parentheses
-(for example, `(C)`) will be interpreted as a list:
-
-    B. Russell was an English philosopher.
-
-    (C) 2007 Joe Smith
-
-To avoid this, use backslash escapes:
-
-    B\. Russell was an English philosopher.
-
-    \(C) 2007 Joe Smith
 
 Definition lists
 ----------------

src/Text/Pandoc/Readers/Markdown.hs

@@ -327,12 +327,15 @@ orderedListStart style delim = try $ do
   optional newline -- if preceded by a Plain block in a list context
   nonindentSpaces
   state <- getState
-  if stateStrict state
-     then do many1 digit
-             char '.'
-             return 1
-     else orderedListMarker style delim 
-  spaceChar
+  num <- if stateStrict state
+            then do many1 digit
+                    char '.'
+                    return 1
+            else orderedListMarker style delim 
+  if delim == Period && (style == UpperAlpha || (style == UpperRoman &&
+     num `elem` [1, 5, 10, 50, 100, 500, 1000]))
+     then char '\t' <|> (spaceChar >> spaceChar)
+     else spaceChar
   skipSpaces
 
 -- parse a line of a list item (start = parser for beginning of list item)

tests/testsuite.native

@@ -180,6 +180,7 @@ Pandoc (Meta [Str "Pandoc",Space,Str "Test",Space,Str "Suite"] ["John MacFarlane
      ] ] ]
 , Para [Str "Should",Space,Str "not",Space,Str "be",Space,Str "a",Space,Str "list",Space,Str "item:"]
 , Para [Str "M",Str ".",Str "A",Str ".",Space,Str "2007"]
+, Para [Str "B",Str ".",Space,Str "Williams"]
 , HorizontalRule
 , Header 1 [Str "Definition",Space,Str "Lists"]
 , Para [Str "Tight",Space,Str "using",Space,Str "spaces:"]

tests/testsuite.txt

@@ -285,6 +285,8 @@ Should not be a list item:
 
 M.A. 2007
 
+B. Williams
+
   *   *   *   *   *
 
 # Definition Lists

tests/writer.context

@@ -403,6 +403,8 @@ Should not be a list item:
 
 M.A. 2007
 
+B. Williams
+
 \thinrule
 
 \section{Definition Lists}

tests/writer.docbook

@@ -648,6 +648,9 @@ These should not be escaped:  \$ \\ \> \[ \{
       <para>
         M.A. 2007
       </para>
+      <para>
+        B. Williams
+      </para>
     </section>
   </section>
   <section>

tests/writer.html

@@ -453,6 +453,8 @@ These should not be escaped:  \$ \\ \> \[ \{
     >Should not be a list item:</p
     ><p
     >M.A. 2007</p
+    ><p
+    >B. Williams</p
     ><hr
      /><h1 id="definition-lists"
     >Definition Lists</h1

tests/writer.latex

@@ -349,6 +349,8 @@ Should not be a list item:
 
 M.A. 2007
 
+B. Williams
+
 \begin{center}\rule{3in}{0.4pt}\end{center}
 
 \section{Definition Lists}

tests/writer.man

@@ -325,6 +325,8 @@ Nested\.
 Should not be a list item:
 .PP
 M\.A\. 2007
+.PP
+B\. Williams
 .PP
    *   *   *   *   *
 .SH Definition Lists

tests/writer.markdown

@@ -288,6 +288,8 @@ Should not be a list item:
 
 M.A. 2007
 
+B. Williams
+
 
 * * * * *
 

tests/writer.native

@@ -180,6 +180,7 @@ Pandoc (Meta [Str "Pandoc",Space,Str "Test",Space,Str "Suite"] ["John MacFarlane
      ] ] ]
 , Para [Str "Should",Space,Str "not",Space,Str "be",Space,Str "a",Space,Str "list",Space,Str "item:"]
 , Para [Str "M",Str ".",Str "A",Str ".",Space,Str "2007"]
+, Para [Str "B",Str ".",Space,Str "Williams"]
 , HorizontalRule
 , Header 1 [Str "Definition",Space,Str "Lists"]
 , Para [Str "Tight",Space,Str "using",Space,Str "spaces:"]

tests/writer.rst

@@ -352,6 +352,8 @@ Should not be a list item:
 
 M.A. 2007
 
+B. Williams
+
 --------------
 
 Definition Lists

tests/writer.rtf

@@ -159,6 +159,7 @@ These should not be escaped:  \\$ \\\\ \\> \\[ \\\{\par}
 {\pard \ql \f0 \sa0 \li720 \fi-360 a.\tx360\tab Nested.\sa180\sa180\par}
 {\pard \ql \f0 \sa180 \li0 \fi0 Should not be a list item:\par}
 {\pard \ql \f0 \sa180 \li0 \fi0 M.A. 2007\par}
+{\pard \ql \f0 \sa180 \li0 \fi0 B. Williams\par}
 {\pard \qc \f0 \sa180 \li0 \fi0 \emdash\emdash\emdash\emdash\emdash\par}
 {\pard \ql \f0 \sa180 \li0 \fi0 \b \fs36 Definition Lists\par}
 {\pard \ql \f0 \sa180 \li0 \fi0 Tight using spaces:\par}