private static IKeyedVariableCollection ToVariableCollection(IEnumerable <string> parameterNames)
{
var result = new KeyedVariableCollection();
foreach (var parameterName in parameterNames)
{
if (result.Contains(parameterName))
{
Errors.ThrowParameterAlreadyDeclared(parameterName);
}
result.Add(parameterName);
}
return(result);
}
private Function ParseFunction(bool isDeclaration)
{
Contract.Requires(_currentFunction != null);
Contract.Ensures(_currentFunction != null);
var startPosition = Lookahead.StartPosition;
Match(TokenType.Function);
string name = null;
if (Lookahead.Type == TokenType.Ident)
{
name = Lookahead.Value;
if (_currentFunction.Outer != null && _currentFunction.Outer.NestedFunctions.Contains(name))
{
Errors.ThrowFunctionAlreadyDeclared(startPosition, name);
}
ReadNextToken();
}
var parameterNames = new KeyedVariableCollection();
Match(TokenType.LParenthesis);
if (Lookahead.Type != TokenType.RParenthesis)
{
if (Lookahead.Type != TokenType.Ident)
{
Errors.ThrowUnmatchedToken(TokenType.Ident, Lookahead);
}
parameterNames.Add(Lookahead.Value);
ReadNextToken();
while (Lookahead.Type == TokenType.Comma)
{
ReadNextToken();
if (Lookahead.Type != TokenType.Ident)
{
Errors.ThrowUnmatchedToken(TokenType.Ident, Lookahead);
}
var parameterName = Lookahead.Value;
if (parameterNames.Contains(parameterName))
{
Errors.ThrowParameterAlreadyDeclared(Lookahead.StartPosition, parameterName);
}
parameterNames.Add(parameterName);
ReadNextToken();
}
}
Match(TokenType.RParenthesis);
_currentFunction = new ParsingFunction(_currentFunction, name, startPosition.LineNo, parameterNames, isDeclaration);
Match(TokenType.LCurlyBrace);
_currentFunction.FunctionBody = ParseFunctionBody();
Match(TokenType.RCurlyBrace);
var result = _currentFunction.ToFunction();
_currentFunction = _currentFunction.Outer;
_currentFunction.NestedFunctions.Add(result);
return(result);
}