From d0326d6abdbcd298240a35605513945ba773456c Mon Sep 17 00:00:00 2001
From: "Kyle J. McKay" <mackyle@gmail.com>
Date: Thu, 19 Jan 2017 18:13:56 -0800
Subject: [PATCH] Markdown.pl: usually (i), (v) and (x) are roman

Only treat (i), (v) and (x) as alpha if the previous
list marker was lower alpha (or upper alpha in the
case of (I), (V) and (X)).

Previously they were treated as alpha if the first
marker in the list was alpha, but if list marker
types were changed mid-list that could lead to
unexpected behavior.

Signed-off-by: Kyle J. McKay <mackyle@gmail.com>
---
 Markdown.pl | 31 +++++++++++++++----------------
 1 file changed, 15 insertions(+), 16 deletions(-)

diff --git a/Markdown.pl b/Markdown.pl
index c676961..d7dec94 100755
--- a/Markdown.pl
+++ b/Markdown.pl
@@ -1194,15 +1194,15 @@ BEGIN {
 
 
 sub _GetListMarkerType {
-    my ($list_type, $list_marker, $first_marker) = @_;
+    my ($list_type, $list_marker, $last_marker) = @_;
     return "" unless $list_type && $list_marker && lc($list_type) eq "ol";
-    unless ($list_marker =~ /^[IiVvXx][.\)]?$/ &&
-	    # these are roman unless $first_marker type is 'a' or 'A'
-	    defined($first_marker) &&
-	    lc(_GetListMarkerType($list_type, $first_marker)) eq 'a') {
-	return "I" if $list_marker =~ /^[IVX]/;
-	return "i" if $list_marker =~ /^[ivx]/;
-    }
+    my $last_marker_type = '';
+    $last_marker_type = _GetListMarkerType($list_type, $last_marker)
+	if defined($last_marker) &&
+	    # these are roman unless $last_marker type case matches and is 'a' or 'A'
+	    $list_marker =~ /^[IiVvXx][.\)]?$/;
+    return "I" if $list_marker =~ /^[IVX]/ && $last_marker_type ne 'A';
+    return "i" if $list_marker =~ /^[ivx]/ && $last_marker_type ne 'a';
     return "A" if $list_marker =~ /^[A-Z]/;
     return "a" if $list_marker =~ /^[a-z]/ || $list_marker =~ /^$greek_lower/o;
     return "1";
@@ -1210,8 +1210,8 @@ sub _GetListMarkerType {
 
 
 sub _GetListItemTypeClass {
-    my ($list_type, $list_marker, $first_marker) = @_;
-    my $list_marker_type = _GetListMarkerType($list_type, $list_marker, $first_marker);
+    my ($list_type, $list_marker, $last_marker) = @_;
+    my $list_marker_type = _GetListMarkerType($list_type, $list_marker, $last_marker);
     my $ans = &{sub{
 	return "" unless length($list_marker) >= 2 && $list_marker_type =~ /^[IiAa1]$/;
 	return "lower-greek" if $list_marker_type eq "a" && $list_marker =~ /^$greek_lower/o;
@@ -1520,7 +1520,7 @@ sub _ProcessListItems {
 	    $oldpos = $-[0]; # point at start of this entire match
 	}
 	if (!defined($first_marker)) {
-	    $first_marker = $last_marker = $list_marker;
+	    $first_marker = $list_marker;
 	    $first_marker_type = _GetListMarkerType($list_type, $first_marker);
 	    if ($first_marker_type) {
 		(my $marker_val = $first_marker) =~ s/[.\)]$//;
@@ -1532,8 +1532,6 @@ sub _ProcessListItems {
 	    # Wrong marker kind, "fix up" the marker to a correct "lazy" marker
 	    # But keep the old length in $list_marker_len
 	    $list_marker = $last_marker;
-	} else {
-	    $last_marker = $list_marker;
 	}
 
 	# Now grab the rest of this item's data upto but excluding the next
@@ -1581,7 +1579,7 @@ sub _ProcessListItems {
 	    $checkbox = "<span><span></span></span><span></span><span>[<tt>$checkbox_val</tt>]&#160;</span>";
 	} else {
 	    my $list_marker_type;
-	    ($list_marker_type, $liatt) = _GetListItemTypeClass($list_type, $list_marker, $first_marker);
+	    ($list_marker_type, $liatt) = _GetListItemTypeClass($list_type, $list_marker, $last_marker);
 	    if ($list_type eq "ol" && defined($first_marker)) {
 		my $styled = $fancy = 1 if $liatt && $list_marker =~ /\)$/;
 		my ($sfx, $dash) = ("", "");
@@ -1594,8 +1592,8 @@ sub _ProcessListItems {
 		$sfx .= "-greek" if $liatt =~ /greek/;
 		$liatt = " class=\"$opt{style_prefix}$sfx\"" if $sfx;
 		$typechanged = 1 if $list_marker_type ne $first_marker_type;
-		$list_marker =~ s/[.\)]$//;
-		my $marker_num = _GetMarkerIntegerNum($list_marker_type, $list_marker);
+		(my $marker_val = $list_marker) =~ s/[.\)]$//;
+		my $marker_num = _GetMarkerIntegerNum($list_marker_type, $marker_val);
 		$marker_num = $next_num if $marker_num < $next_num;
 		$skipped = 1 if $next_num < $marker_num;
 		$incr = _IncrList($next_num, $marker_num, "incrlevel=$g_list_level");
@@ -1604,6 +1602,7 @@ sub _ProcessListItems {
 		$next_num = $marker_num + 1;
 	    }
 	}
+	$last_marker = $list_marker;
 
 	if ($leading_line or ($item =~ m/\n{2,}/)) {
 	    $item = _RunBlockGamut(_Outdent($item));