private void AppendRawNode(StringBuilder builder, string source, Shortcode node)
{
if (node.OpenBraces == node.CloseBraces)
{
builder.Append(source, node.SourceIndex, node.SourceLength + node.CloseBraces);
}
else
{
builder.Append(source, node.SourceIndex, node.SourceLength + 1);
}
}
public bool ReadShortcode(out Shortcode shortcode)
{
shortcode = null;
var style = ShortcodeStyle.Open;
if (_cursor.Char != '[')
{
return(false);
}
CreateCursor();
_cursor.Advance();
// Is it a closing tag?
if (_cursor.Char == '/')
{
style = ShortcodeStyle.Close;
_cursor.Advance();
}
// Reach Eof before end of shortcode
if (_cursor.Eof)
{
DiscardCursor();
return(false);
}
SkipWhiteSpace();
if (!ReadIdentifier())
{
DiscardCursor();
return(false);
}
Token identifier = _token;
SkipWhiteSpace();
Dictionary <string, string> arguments = null;
int argumentIndex = 0;
// Arguments?
while (ReadIdentifier() || ReadString())
{
// Is it a positioned argument?
if (_token.Type == "string")
{
arguments ??= new Dictionary <string, string>();
arguments[argumentIndex.ToString()] = DecodeString(_token.ToString());
argumentIndex += 1;
SkipWhiteSpace();
}
else
{
var argument = _token;
SkipWhiteSpace();
if (!ReadEqualSign())
{
DiscardCursor();
return(false);
}
SkipWhiteSpace();
if (ReadString())
{
arguments ??= new Dictionary <string, string>();
arguments[argument.ToString()] = DecodeString(_token.ToString());
}
else
{
DiscardCursor();
return(false);
}
SkipWhiteSpace();
}
}
// Is it a self-closing tag?
if (_cursor.Char == '/' && _cursor.PeekNext() == ']')
{
style = ShortcodeStyle.SelfClosing;
_cursor.Advance();
}
// Expect closing bracket
if (_cursor.Char != ']')
{
DiscardCursor();
return(false);
}
// Ignore shortcode if the next char is also ']', making it a comment
if (_cursor.PeekNext() == ']')
{
DiscardCursor();
return(false);
}
shortcode = new Shortcode(identifier.ToString(), style);
shortcode.Arguments = new Arguments(arguments);
PromoteCursor();
return(true);
}
private Shortcode ParseShortcode()
{
// Number of opening braces
var openBraces = 0;
// Number of closing braces
var closeBraces = 0;
Shortcode shortcode;
var style = ShortcodeStyle.Open;
// Start position of the shortcode
var start = _scanner.Cursor.Position;
if (!_scanner.ReadChar('['))
{
return(null);
}
openBraces += 1;
// Read all '[' so we can detect escaped tags
while (_scanner.ReadChar('['))
{
openBraces += 1;
}
// Is it a closing tag?
if (_scanner.ReadChar('/'))
{
style = ShortcodeStyle.Close;
}
// Reach Eof before end of shortcode
if (_scanner.Cursor.Eof)
{
_scanner.Cursor.ResetPosition(start);
return(null);
}
_scanner.SkipWhiteSpace();
if (!_scanner.ReadIdentifier(_result))
{
_scanner.Cursor.ResetPosition(start);
return(null);
}
var identifier = _result.Text;
_scanner.SkipWhiteSpace();
Dictionary <string, string> arguments = null;
int argumentIndex = 0;
// Arguments?
while (!_scanner.Cursor.Eof)
{
// Record location in case it doesn't have a value
var argumentStart = _scanner.Cursor.Position;
if (_scanner.ReadQuotedString(_result))
{
arguments ??= CreateArgumentsDictionary();
arguments[argumentIndex.ToString()] = Character.DecodeString(_result.Span.Slice(1, _result.Length - 2)).ToString();
argumentIndex += 1;
}
else if (_scanner.ReadIdentifier(_result))
{
_scanner.SkipWhiteSpace();
var argumentName = _result.Text;
// It might just be a value
if (_scanner.ReadChar('='))
{
_scanner.SkipWhiteSpace();
if (_scanner.ReadQuotedString(_result))
{
arguments ??= CreateArgumentsDictionary();
arguments[argumentName] = Character.DecodeString(_result.Span.Slice(1, _result.Length - 2)).ToString();
}
else if (_scanner.ReadValue(_result))
{
arguments ??= CreateArgumentsDictionary();
arguments[argumentName] = _result.Text.ToString();
}
else
{
_scanner.Cursor.ResetPosition(start);
return(null);
}
}
else
{
// Positional argument that looks like an identifier
_scanner.Cursor.ResetPosition(argumentStart);
if (_scanner.ReadValue(_result))
{
arguments ??= CreateArgumentsDictionary();
arguments[argumentIndex.ToString()] = _result.Text;
argumentIndex += 1;
}
else
{
_scanner.Cursor.ResetPosition(start);
break;
}
}
}
else if (_scanner.ReadValue(_result))
{
arguments ??= CreateArgumentsDictionary();
arguments[argumentIndex.ToString()] = _result.Text;
argumentIndex += 1;
}
else if (_scanner.Cursor.Match("/]"))
{
style = ShortcodeStyle.SelfClosing;
_scanner.Cursor.Advance();
break;
}
else if (_scanner.Cursor.Match(']'))
{
break;
}
else
{
_scanner.Cursor.ResetPosition(start);
return(null);
}
_scanner.SkipWhiteSpace();
}
// If we exited the loop due to EOF, exit
if (_scanner.Cursor.Eof || !_scanner.ReadChar(']'))
{
_scanner.Cursor.ResetPosition(start);
return(null);
}
closeBraces += 1;
// Read all ']' so we can detect escaped tags
while (_scanner.ReadChar(']'))
{
closeBraces += 1;
}
shortcode = new Shortcode(
identifier,
style,
openBraces,
closeBraces,
start.Offset,
_scanner.Cursor.Position - start - 1,
new Arguments(arguments)
);
return(shortcode);
public bool ReadShortcode(out Shortcode shortcode)
{
// Number of opening braces
var openBraces = 0;
// Number of closing braces
var closeBraces = 0;
shortcode = null;
var style = ShortcodeStyle.Open;
if (_cursor.Char != '[')
{
return(false);
}
CreateCursor();
// Start position of the shortcode
var index = _cursor.Offset;
// Read all '[' so we can detect escaped tags
do
{
openBraces += 1;
_cursor.Advance();
} while (_cursor.Char == '[');
// Is it a closing tag?
if (_cursor.Char == '/')
{
style = ShortcodeStyle.Close;
_cursor.Advance();
}
// Reach Eof before end of shortcode
if (_cursor.Eof)
{
DiscardCursor();
return(false);
}
SkipWhiteSpace();
if (!ReadIdentifier())
{
DiscardCursor();
return(false);
}
Token identifier = _token;
SkipWhiteSpace();
Dictionary <string, string> arguments = null;
int argumentIndex = 0;
// Arguments?
while (true)
{
if (ReadString())
{
arguments ??= CreateArgumentsDictionary();
arguments[argumentIndex.ToString()] = DecodeString(_token.ToString());
argumentIndex += 1;
}
else if (ReadIdentifier())
{
var argument = _token;
SkipWhiteSpace();
// It might just be a value
if (ReadEqualSign())
{
SkipWhiteSpace();
if (ReadString())
{
arguments ??= CreateArgumentsDictionary();
arguments[argument.ToString()] = DecodeString(_token.ToString());
}
else if (ReadValue())
{
arguments ??= CreateArgumentsDictionary();
arguments[argument.ToString()] = _token.ToString();
}
else
{
DiscardCursor();
return(false);
}
}
else
{
// Positional argument that looks like an identifier
_cursor.Seek(argument.Start);
if (ReadValue())
{
arguments ??= CreateArgumentsDictionary();
arguments[argumentIndex.ToString()] = _token.ToString();
argumentIndex += 1;
}
else
{
_cursor.Seek(argument.Start);
break;
}
}
}
else if (ReadValue())
{
arguments ??= CreateArgumentsDictionary();
arguments[argumentIndex.ToString()] = _token.ToString();
argumentIndex += 1;
}
else
{
break;
}
SkipWhiteSpace();
}
// Is it a self-closing tag?
if (_cursor.Char == '/' && _cursor.PeekNext() == ']')
{
style = ShortcodeStyle.SelfClosing;
_cursor.Advance();
}
// Expect closing bracket
if (_cursor.Char != ']')
{
DiscardCursor();
return(false);
}
// Read all ']' so we can detect escaped tags
do
{
closeBraces += 1;
_cursor.Advance();
} while (_cursor.Char == ']');
shortcode = new Shortcode(identifier.ToString(), style, openBraces, closeBraces, index, _cursor.Offset - index - 1);
shortcode.Arguments = new Arguments(arguments);
PromoteCursor();
return(true);
// Local function to use the same logic to create the arguments dictionary
Dictionary <string, string> CreateArgumentsDictionary()
{
return(new Dictionary <string, string>(StringComparer.OrdinalIgnoreCase));
}
}
private async ValueTask <string> FoldClosingTagsAsync(string input, List <Node> nodes, int index, int length, Context context)
{
// This method should not be called when nodes has a single RawText element.
// It's implementation assumes at least two nodes are provided.
using var sb = StringBuilderPool.GetInstance();
// The index of the next shortcode opening node
var cursor = index;
// Process the list
while (cursor <= index + length - 1)
{
Shortcode start = null;
var head = 0;
var tail = 0;
// Find the next opening tag
while (cursor <= index + length - 1 && start == null)
{
var node = nodes[cursor];
if (node is Shortcode shortCode)
{
if (shortCode.Style == ShortcodeStyle.Open)
{
head = cursor;
start = shortCode;
}
else
{
// These closing tags need to be rendered
sb.Builder.Append(input, shortCode.SourceIndex, shortCode.SourceLength + 1);
}
}
else
{
var text = node as RawText;
sb.Builder.Append(text.Buffer, text.Offset, text.Count);
}
cursor += 1;
}
// if start is null, then there is nothing to fold
if (start == null)
{
return(sb.Builder.ToString());
}
Shortcode end = null;
var depth = 1;
// Find a matching closing tag
while (cursor <= index + length - 1 && end == null)
{
if (nodes[cursor] is Shortcode shortCode)
{
if (String.Equals(start.Identifier, shortCode.Identifier, StringComparison.OrdinalIgnoreCase))
{
if (shortCode.Style == ShortcodeStyle.Open)
{
// We need to count all opening shortcodes matching the start to account for:
// [a] [a] [/a] [/a]
depth += 1;
}
else
{
depth -= 1;
if (depth == 0)
{
tail = cursor;
end = shortCode;
}
}
}
}
cursor += 1;
}
// Is it a single tag?
if (end == null)
{
cursor = head + 1;
// If there are more than one open/close brace we don't evaluate the shortcode
if (start.OpenBraces > 1 || start.CloseBraces > 1)
{
// We need to escape the braces if counts match
var bracesToSkip = start.OpenBraces == start.CloseBraces ? 1 : 0;
sb.Builder.Append('[', start.OpenBraces - bracesToSkip);
sb.Builder.Append(input, start.SourceIndex + start.OpenBraces, start.SourceLength - start.CloseBraces - start.OpenBraces + 1);
sb.Builder.Append(']', start.CloseBraces - bracesToSkip);
}
else
{
await AppendAsync(sb.Builder, input, start, null, context);
}
}
else
{
// Standard braces are made of 1 brace on each edge
var standardBraces = start.OpenBraces == 1 && start.CloseBraces == 1 && end.OpenBraces == 1 && end.CloseBraces == 1;
var balancedBraces = start.OpenBraces == end.CloseBraces && start.CloseBraces == end.OpenBraces;
if (standardBraces)
{
// Are the tags adjacent?
if (tail - head == 1)
{
start.Content = "";
await AppendAsync(sb.Builder, input, start, end, context);
}
// Is there a single node between the tags?
else if (tail - head == 2)
{
// Render the inner node (raw or shortcode)
var content = nodes[head + 1];
// Set it to the start shortcode
using (var sbContent = StringBuilderPool.GetInstance())
{
await AppendAsync(sbContent.Builder, input, content, null, context);
start.Content = sbContent.ToString();
}
// Render the start shortcode
await AppendAsync(sb.Builder, input, start, end, context);
}
// Fold the inner nodes
else
{
start.Content = await FoldClosingTagsAsync(input, nodes, head + 1, tail - head - 1, context);
await AppendAsync(sb.Builder, input, start, end, context);
}
}
else
{
// Balanced braces represent an escape sequence, e.g. [[upper]foo[/upper]] -> [upper]foo[/upper]
if (balancedBraces)
{
var bracesToSkip = start.OpenBraces == end.CloseBraces ? 1 : 0;
sb.Builder.Append('[', start.OpenBraces - bracesToSkip);
sb.Builder.Append(input, start.SourceIndex + start.OpenBraces, end.SourceIndex + end.SourceLength - end.CloseBraces - start.SourceIndex - start.OpenBraces + 1);
sb.Builder.Append(']', end.CloseBraces - bracesToSkip);
}
// Unbalanced braces only evaluate inner content, e.g. [upper]foo[/upper]]
else
{
// Are the tags adjacent?
if (tail - head == 1)
{
AppendRawNode(sb.Builder, input, start);
AppendRawNode(sb.Builder, input, end);
}
// Is there a single node between the tags?
else if (tail - head == 2)
{
// Render the inner node (raw or shortcode)
var content = nodes[head + 1];
AppendRawNode(sb.Builder, input, start);
await AppendAsync(sb.Builder, input, content, null, context);
AppendRawNode(sb.Builder, input, end);
}
// Fold the inner nodes
else
{
var content = await FoldClosingTagsAsync(input, nodes, head + 1, tail - head - 1, context);
AppendRawNode(sb.Builder, input, start);
sb.Builder.Append(content);
AppendRawNode(sb.Builder, input, end);
}
}
}
}
}
return(sb.Builder.ToString());
}
private async Task AppendAsync(StringBuilder builder, string source, Node start, Shortcode end, Context context)
{
switch (start)
{
case RawText raw:
builder.Append(raw.Buffer, raw.Offset, raw.Count);
return;
case Shortcode code:
foreach (var provider in Providers)
{
var result = await provider.EvaluateAsync(code.Identifier, code.Arguments, code.Content, context);
if (result != null)
{
builder.Append(result);
return;
}
}
// Return original content if no handler is found
if (end == null)
{
// No closing tag
builder.Append(source, code.SourceIndex, code.SourceLength + code.CloseBraces);
}
else
{
builder
.Append(source, code.SourceIndex, code.SourceLength + code.CloseBraces)
.Append(code.Content)
.Append(source, end.SourceIndex, end.SourceLength + end.CloseBraces)
;
}
break;
default:
throw new NotSupportedException();
}
}
private async ValueTask <string> FoldClosingTagsAsync(string input, List <Node> nodes, int index, int length, Context context)
{
// This method should not be called when nodes has a single RawText element.
// It's implementation assumes at least two nodes are provided.
using var sb = StringBuilderPool.GetInstance();
// The index of the next shortcode opening node
var cursor = index;
// Process the list
while (cursor <= index + length - 1)
{
Shortcode start = null;
var head = 0;
var tail = 0;
// Find the next opening tag
while (cursor < nodes.Count && start == null)
{
var node = nodes[cursor];
if (node is Shortcode shortCode)
{
if (shortCode.Style == ShortcodeStyle.Open)
{
head = cursor;
start = shortCode;
}
}
else
{
var text = node as RawText;
sb.Builder.Append(text.Text);
}
cursor += 1;
}
// if start is null, then there is nothing to fold
if (start == null)
{
return(sb.Builder.ToString());
}
Shortcode end = null;
var depth = 1;
// Find a matching closing tag
while (cursor <= index + length - 1 && end == null)
{
if (nodes[cursor] is Shortcode shortCode)
{
if (String.Equals(start.Identifier, shortCode.Identifier, StringComparison.OrdinalIgnoreCase))
{
if (shortCode.Style == ShortcodeStyle.Open)
{
// We need to count all opening shortcodes matching the start to account for:
// [a] [a] [/a] [/a]
depth += 1;
}
else
{
depth -= 1;
if (depth == 0)
{
tail = cursor;
end = shortCode;
}
}
}
}
cursor += 1;
}
// Is is a single tag?
if (end == null)
{
cursor = head + 1;
// If there are more than one open/close brace we don't evaluate the shortcode
if (start.OpenBraces > 1 || start.CloseBraces > 1)
{
// We need to escape the braces if counts match
var bracesToSkip = start.OpenBraces == start.CloseBraces ? 1 : 0;
sb.Builder.Append('[', start.OpenBraces - bracesToSkip);
sb.Builder.Append(input.Substring(start.SourceIndex + start.OpenBraces, start.SourceLength - start.CloseBraces - start.OpenBraces + 1));
sb.Builder.Append(']', start.CloseBraces - bracesToSkip);
}
else
{
sb.Builder.Append(await RenderAsync(start, context));
}
}
else
{
// If the braces are unbalanced we can't render the shortcode
var canRenderShortcode = start.OpenBraces == 1 && start.CloseBraces == 1 && end.OpenBraces == 1 && end.CloseBraces == 1;
if (canRenderShortcode)
{
// Are the tags adjacent?
if (tail - head == 1)
{
start.Content = "";
sb.Builder.Append(await RenderAsync(start, context));
}
// Is there a single Raw text between the tags?
else if (tail - head == 2)
{
var content = nodes[head + 1] as RawText;
start.Content = content.Text;
sb.Builder.Append(await RenderAsync(start, context));
}
// Fold the inner nodes
else
{
var content = await FoldClosingTagsAsync(input, nodes, head + 1, tail - head - 1, context);
start.Content = content;
sb.Builder.Append(await RenderAsync(start, context));
}
}
else
{
var bracesToSkip = start.OpenBraces == end.CloseBraces ? 1 : 0;
sb.Builder.Append('[', start.OpenBraces - bracesToSkip);
sb.Builder.Append(input.Substring(start.SourceIndex + start.OpenBraces, end.SourceIndex + end.SourceLength - end.CloseBraces - start.SourceIndex - start.OpenBraces + 1));
sb.Builder.Append(']', end.CloseBraces - bracesToSkip);
}
}
}
return(sb.Builder.ToString());
}