public static ExpressionNode Parse(Reader r)
{
var nodes = new List<ExpressionNode>();
var state = State.Start;
while (!r.End && state != State.End)
{
switch (state)
{
case State.Start:
state = ParseStart(r, nodes);
break;
case State.AfterMember:
state = ParseAfterMember(r, nodes);
break;
case State.BeforeMember:
state = ParseBeforeMember(r, nodes);
break;
}
}
if (state == State.BeforeMember)
{
throw new ExpressionParseException(r.Position, "Unexpected end of expression.");
}
for (int n = 0; n < nodes.Count - 1; ++n)
{
nodes[n].Next = nodes[n + 1];
}
return nodes.FirstOrDefault();
}
public static IList<object> Parse(Reader r, char open, char close)
{
if (r.Peek == open)
{
var result = new List<object>();
r.Take();
while (!r.End)
{
var literal = LiteralParser.Parse(r);
if (literal != null)
{
result.Add(literal);
}
else
{
throw new ExpressionParseException(r.Position, "Expected integer.");
}
r.SkipWhitespace();
if (r.End)
{
throw new ExpressionParseException(r.Position, "Expected ','.");
}
else if (r.TakeIf(close))
{
return result;
}
else
{
if (r.Take() != ',')
{
throw new ExpressionParseException(r.Position, "Expected ','.");
}
r.SkipWhitespace();
}
}
if (!r.End)
{
r.Take();
return result;
}
else
{
throw new ExpressionParseException(r.Position, "Expected ']'.");
}
}
return null;
}
public static IList<string> Parse(Reader r, char open, char close)
{
if (r.Peek == open)
{
var result = new List<string>();
r.Take();
while (!r.End)
{
var builder = new StringBuilder();
while (!r.End && r.Peek != ',' && r.Peek != close && !char.IsWhiteSpace(r.Peek))
{
builder.Append(r.Take());
}
if (builder.Length == 0)
{
throw new ExpressionParseException(r.Position, "Expected indexer argument.");
}
result.Add(builder.ToString());
r.SkipWhitespace();
if (r.End)
{
throw new ExpressionParseException(r.Position, "Expected ','.");
}
else if (r.TakeIf(close))
{
return result;
}
else
{
if (r.Take() != ',')
{
throw new ExpressionParseException(r.Position, "Expected ','.");
}
r.SkipWhitespace();
}
}
if (!r.End)
{
r.Take();
return result;
}
else
{
throw new ExpressionParseException(r.Position, "Expected ']'.");
}
}
return null;
}
public static ExpressionNode Build(string expression)
{
if (string.IsNullOrWhiteSpace(expression))
{
throw new ArgumentException("'expression' may not be empty.");
}
var reader = new Reader(expression);
var node = ExpressionParser.Parse(reader);
if (!reader.End)
{
throw new ExpressionParseException(reader.Position, "Expected end of expression.");
}
return node;
}
public static string Parse(Reader r)
{
if (IsValidIdentifierStart(r.Peek))
{
var result = new StringBuilder();
while (!r.End && IsValidIdentifierChar(r.Peek))
{
result.Append(r.Take());
}
return result.ToString();
}
else
{
return null;
}
}
private static State ParseStart(Reader r, IList<ExpressionNode> nodes)
{
if (ParseNot(r))
{
nodes.Add(new LogicalNotNode());
return State.Start;
}
else
{
var identifier = IdentifierParser.Parse(r);
if (identifier != null)
{
nodes.Add(new PropertyAccessorNode(identifier));
return State.AfterMember;
}
}
return State.End;
}
public static object Parse(Reader r)
{
if (char.IsDigit(r.Peek))
{
StringBuilder result = new StringBuilder();
while (!r.End)
{
if (char.IsDigit(r.Peek))
{
result.Append(r.Take());
}
else
{
break;
}
}
return int.Parse(result.ToString(), CultureInfo.InvariantCulture);
}
return null;
}
private static State ParseAfterMember(Reader r, IList<ExpressionNode> nodes)
{
if (ParseMemberAccessor(r))
{
return State.BeforeMember;
}
else
{
var args = ArgumentListParser.Parse(r, '[', ']');
if (args != null)
{
if (args.Count == 0)
{
throw new ExpressionParseException(r.Position, "Indexer may not be empty.");
}
nodes.Add(new IndexerNode(args));
return State.AfterMember;
}
}
return State.End;
}
private static State ParseBeforeMember(Reader r, IList<ExpressionNode> nodes)
{
var identifier = IdentifierParser.Parse(r);
if (identifier != null)
{
nodes.Add(new PropertyAccessorNode(identifier));
return State.AfterMember;
}
return State.End;
}
private static bool ParseMemberAccessor(Reader r)
{
return !r.End && r.TakeIf('.');
}
private static bool ParseNot(Reader r)
{
return !r.End && r.TakeIf('!');
}
internal ExpressionParseException(Reader r, string message)
: this(r.Position, message)
{
}