/// <summary>
/// Parsing helper method.
/// </summary>
private static void AppendTextToListItem(ListItemBlock listItem, string markdown, int start, int end, bool newLine = false)
{
ListItemBuilder listItemBuilder = null;
if (listItem.Blocks.Count > 0)
{
listItemBuilder = listItem.Blocks[listItem.Blocks.Count - 1] as ListItemBuilder;
}
if (listItemBuilder == null)
{
// Add a new block.
listItemBuilder = new ListItemBuilder();
listItem.Blocks.Add(listItemBuilder);
}
var builder = listItemBuilder.Builder;
if (builder.Length >= 2 &&
ParseHelpers.IsMarkdownWhiteSpace(builder[builder.Length - 2]) &&
ParseHelpers.IsMarkdownWhiteSpace(builder[builder.Length - 1]))
{
builder.Length -= 2;
builder.AppendLine();
}
else if (builder.Length > 0)
{
builder.Append(' ');
}
if (newLine)
{
builder.Append(Environment.NewLine);
}
builder.Append(markdown.Substring(start, end - start));
}
/// <summary>
/// Parses a list block.
/// </summary>
/// <param name="markdown"> The markdown text. </param>
/// <param name="start"> The location of the first character in the block. </param>
/// <param name="maxEnd"> The location to stop parsing. </param>
/// <param name="quoteDepth"> The current nesting level for block quoting. </param>
/// <param name="actualEnd"> Set to the end of the block when the return value is non-null. </param>
/// <returns> A parsed list block, or <c>null</c> if this is not a list block. </returns>
internal static ListBlock Parse(string markdown, int start, int maxEnd, int quoteDepth, out int actualEnd)
{
var russianDolls = new List <NestedListInfo>();
int russianDollIndex = -1;
bool previousLineWasBlank = false;
bool inCodeBlock = false;
ListItemBlock currentListItem = null;
actualEnd = start;
foreach (var lineInfo in Common.ParseLines(markdown, start, maxEnd, quoteDepth))
{
// Is this line blank?
if (lineInfo.IsLineBlank)
{
// The line is blank, which means the next line which contains text may end the list (or it may not...).
previousLineWasBlank = true;
}
else
{
// Does the line contain a list item?
ListItemPreamble listItemPreamble = null;
if (lineInfo.FirstNonWhitespaceChar - lineInfo.StartOfLine < (russianDollIndex + 2) * 4)
{
listItemPreamble = ParseItemPreamble(markdown, lineInfo.FirstNonWhitespaceChar, lineInfo.EndOfLine);
}
if (listItemPreamble != null)
{
// Yes, this line contains a list item.
// Determining the nesting level is done as follows:
// 1. If this is the first line, then the list is not nested.
// 2. If the number of spaces at the start of the line is equal to that of
// an existing list, then the nesting level is the same as that list.
// 3. Otherwise, if the number of spaces is 0-4, then the nesting level
// is one level deep.
// 4. Otherwise, if the number of spaces is 5-8, then the nesting level
// is two levels deep (but no deeper than one level more than the
// previous list item).
// 5. Etcetera.
ListBlock listToAddTo = null;
int spaceCount = lineInfo.FirstNonWhitespaceChar - lineInfo.StartOfLine;
russianDollIndex = russianDolls.FindIndex(rd => rd.SpaceCount == spaceCount);
if (russianDollIndex >= 0)
{
// Add the new list item to an existing list.
listToAddTo = russianDolls[russianDollIndex].List;
// Don't add new list items to items higher up in the list.
russianDolls.RemoveRange(russianDollIndex + 1, russianDolls.Count - (russianDollIndex + 1));
}
else
{
russianDollIndex = Math.Max(1, 1 + ((spaceCount - 1) / 4));
if (russianDollIndex < russianDolls.Count)
{
// Add the new list item to an existing list.
listToAddTo = russianDolls[russianDollIndex].List;
// Don't add new list items to items higher up in the list.
russianDolls.RemoveRange(russianDollIndex + 1, russianDolls.Count - (russianDollIndex + 1));
}
else
{
// Create a new list.
listToAddTo = new ListBlock {
Style = listItemPreamble.Style, Items = new List <ListItemBlock>()
};
if (russianDolls.Count > 0)
{
currentListItem.Blocks.Add(listToAddTo);
}
russianDollIndex = russianDolls.Count;
russianDolls.Add(new NestedListInfo {
List = listToAddTo, SpaceCount = spaceCount
});
}
}
// Add a new list item.
currentListItem = new ListItemBlock()
{
Blocks = new List <MarkdownBlock>()
};
listToAddTo.Items.Add(currentListItem);
// Add the rest of the line to the builder.
AppendTextToListItem(currentListItem, markdown, listItemPreamble.ContentStartPos, lineInfo.EndOfLine);
}
else
{
// No, this line contains text.
// Is there even a list in progress?
if (currentListItem == null)
{
actualEnd = start;
return(null);
}
// This is the start of a new paragraph.
int spaceCount = lineInfo.FirstNonWhitespaceChar - lineInfo.StartOfLine;
if (spaceCount == 0)
{
break;
}
russianDollIndex = Math.Min(russianDollIndex, (spaceCount - 1) / 4);
int lineStart = Math.Min(lineInfo.FirstNonWhitespaceChar, lineInfo.StartOfLine + ((russianDollIndex + 1) * 4));
// 0 spaces = end of the list.
// 1-4 spaces = first level.
// 5-8 spaces = second level, etc.
if (previousLineWasBlank)
{
ListBlock listToAddTo = russianDolls[russianDollIndex].List;
currentListItem = listToAddTo.Items[listToAddTo.Items.Count - 1];
ListItemBuilder builder;
// Prevents new Block creation if still in a Code Block.
if (!inCodeBlock)
{
builder = new ListItemBuilder();
currentListItem.Blocks.Add(builder);
}
else
{
// This can only ever be a ListItemBuilder, so it is not a null reference.
builder = currentListItem.Blocks.Last() as ListItemBuilder;
// Make up for the escaped NewLines.
builder.Builder.AppendLine();
builder.Builder.AppendLine();
}
AppendTextToListItem(currentListItem, markdown, lineStart, lineInfo.EndOfLine);
}
else
{
// Inline text. Ignores the 4 spaces that are used to continue the list.
AppendTextToListItem(currentListItem, markdown, lineStart, lineInfo.EndOfLine, true);
}
}
// Check for Closing Code Blocks.
if (currentListItem.Blocks.Last() is ListItemBuilder currentBlock)
{
var blockMatchCount = Regex.Matches(currentBlock.Builder.ToString(), "```").Count;
if (blockMatchCount > 0 && blockMatchCount % 2 != 0)
{
inCodeBlock = true;
}
else
{
inCodeBlock = false;
}
}
// The line was not blank.
previousLineWasBlank = false;
}
// Go to the next line.
actualEnd = lineInfo.EndOfLine;
}
var result = russianDolls[0].List;
ReplaceStringBuilders(result);
return(result);
}