/// <summary>Attempts to parse key values from the specified text.</summary>
/// <param name='text'>Text to parse (not null).</param>
/// <param name="allowNamedValues">Set to true if the parser should accept named values
/// so syntax like Name='value'. If this is false, the parsing will fail on such constructs.</param>
/// <param name="allowNull">Set to true if the parser should accept null values.
/// If set to false, the parser will fail on null values.</param>
/// <param name='instance'>After invocation, the parsed key instance.</param>
/// <returns>
/// true if the key instance was parsed; false if there was a
/// syntactic error.
/// </returns>
/// <remarks>
/// The returned instance contains only string values. To get typed values, a call to
/// <see cref="TryConvertValues"/> is necessary.
/// </remarks>
private static bool TryParseFromUri(string text, bool allowNamedValues, bool allowNull, out KeyInstance instance)
{
Debug.Assert(text != null, "text != null");
Dictionary <string, object> namedValues = null;
List <object> positionalValues = null;
ExpressionLexer lexer = new ExpressionLexer(text);
Token currentToken = lexer.CurrentToken;
if (currentToken.Id == TokenId.End)
{
instance = Empty;
return(true);
}
instance = null;
do
{
if (currentToken.Id == TokenId.Identifier && allowNamedValues)
{
// Name-value pair.
if (positionalValues != null)
{
// We cannot mix named and non-named values.
return(false);
}
string identifier = lexer.CurrentToken.GetIdentifier();
lexer.NextToken();
if (lexer.CurrentToken.Id != TokenId.Equal)
{
return(false);
}
lexer.NextToken();
if (!lexer.CurrentToken.IsKeyValueToken)
{
return(false);
}
string namedValue = lexer.CurrentToken.Text;
WebUtil.CreateIfNull(ref namedValues);
if (namedValues.ContainsKey(identifier))
{
// Duplicate name.
return(false);
}
namedValues.Add(identifier, namedValue);
}
else if (currentToken.IsKeyValueToken || (allowNull && currentToken.Id == TokenId.NullLiteral))
{
// Positional value.
if (namedValues != null)
{
// We cannot mix named and non-named values.
return(false);
}
WebUtil.CreateIfNull(ref positionalValues);
positionalValues.Add(lexer.CurrentToken.Text);
}
else
{
return(false);
}
// Read the next token. We should be at the end, or find
// we have a comma followed by something.
lexer.NextToken();
currentToken = lexer.CurrentToken;
if (currentToken.Id == TokenId.Comma)
{
lexer.NextToken();
currentToken = lexer.CurrentToken;
if (currentToken.Id == TokenId.End)
{
// Trailing comma.
return(false);
}
}
}while (currentToken.Id != TokenId.End);
instance = new KeyInstance(namedValues, positionalValues);
return(true);
}
private static bool TryParseFromUri(string text, bool allowNamedValues, bool allowNull, out KeyInstance instance)
{
Dictionary <string, object> dictionary = null;
List <object> list = null;
ExpressionLexer lexer = new ExpressionLexer(text);
Token currentToken = lexer.CurrentToken;
if (currentToken.Id == TokenId.End)
{
instance = Empty;
return(true);
}
instance = null;
do
{
if ((currentToken.Id == TokenId.Identifier) && allowNamedValues)
{
if (list != null)
{
return(false);
}
string identifier = lexer.CurrentToken.GetIdentifier();
lexer.NextToken();
if (lexer.CurrentToken.Id != TokenId.Equal)
{
return(false);
}
lexer.NextToken();
if (!lexer.CurrentToken.IsKeyValueToken)
{
return(false);
}
string str2 = lexer.CurrentToken.Text;
WebUtil.CreateIfNull <Dictionary <string, object> >(ref dictionary);
if (dictionary.ContainsKey(identifier))
{
return(false);
}
dictionary.Add(identifier, str2);
}
else
{
if (!currentToken.IsKeyValueToken && (!allowNull || (currentToken.Id != TokenId.NullLiteral)))
{
return(false);
}
if (dictionary != null)
{
return(false);
}
WebUtil.CreateIfNull <List <object> >(ref list);
list.Add(lexer.CurrentToken.Text);
}
lexer.NextToken();
currentToken = lexer.CurrentToken;
if (currentToken.Id == TokenId.Comma)
{
lexer.NextToken();
currentToken = lexer.CurrentToken;
if (currentToken.Id == TokenId.End)
{
return(false);
}
}
}while (currentToken.Id != TokenId.End);
instance = new KeyInstance(dictionary, list);
return(true);
}