/// <summary>
/// Parses a table block.
/// </summary>
/// <param name="markdown"> The markdown text. </param>
/// <param name="start"> The location of the first character in the block. </param>
/// <param name="endOfFirstLine"> The location of the end of the first line. </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 table block, or <c>null</c> if this is not a table block. </returns>
internal static TableBlock Parse(string markdown, int start, int endOfFirstLine, int maxEnd, int quoteDepth, out int actualEnd)
{
// A table is a line of text, with at least one vertical bar (|), followed by a line of
// of text that consists of alternating dashes (-) and vertical bars (|) and optionally
// vertical bars at the start and end. The second line must have at least as many
// interior vertical bars as there are interior vertical bars on the first line.
actualEnd = start;
// First thing to do is to check if there is a vertical bar on the line.
int barOrNewLineIndex = markdown.IndexOf('|', start, endOfFirstLine - start);
if (barOrNewLineIndex < 0)
return null;
var rows = new List<TableRow>();
// Parse the first row.
var firstRow = new TableRow();
start = firstRow.Parse(markdown, start, maxEnd, quoteDepth);
rows.Add(firstRow);
// Parse the contents of the second row.
var secondRowContents = new List<string>();
start = TableRow.ParseContents(markdown, start, maxEnd, quoteDepth, requireVerticalBar: false,
contentParser: (start2, end2) => secondRowContents.Add(markdown.Substring(start2, end2 - start2)));
// There must be at least as many columns in the second row as in the first row.
if (secondRowContents.Count < firstRow.Cells.Count)
return null;
// Check each column definition.
// Note: excess columns past firstRowColumnCount are ignored and can contain anything.
var columnDefinitions = new List<TableColumnDefinition>(firstRow.Cells.Count);
for (int i = 0; i < firstRow.Cells.Count; i++)
{
var cellContent = secondRowContents[i];
if (cellContent.Length == 0)
return null;
// The first and last characters can be '-' or ':'.
if (cellContent[0] != ':' && cellContent[0] != '-')
return null;
if (cellContent[cellContent.Length - 1] != ':' && cellContent[cellContent.Length - 1] != '-')
return null;
// Every other character must be '-'.
for (int j = 1; j < cellContent.Length - 1; j++)
if (cellContent[j] != '-')
return null;
// Record the alignment.
var columnDefinition = new TableColumnDefinition();
if (cellContent.Length > 1 && cellContent[0] == ':' && cellContent[cellContent.Length - 1] == ':')
columnDefinition.Alignment = ColumnAlignment.Center;
else if (cellContent[0] == ':')
columnDefinition.Alignment = ColumnAlignment.Left;
else if (cellContent[cellContent.Length - 1] == ':')
columnDefinition.Alignment = ColumnAlignment.Right;
columnDefinitions.Add(columnDefinition);
}
// Parse additional rows.
while (start < maxEnd)
{
var row = new TableRow();
start = row.Parse(markdown, start, maxEnd, quoteDepth);
if (row.Cells.Count == 0)
break;
rows.Add(row);
}
actualEnd = start;
return new TableBlock { ColumnDefinitions = columnDefinitions, Rows = rows };
}
