Arithmetica.Tokenization.Rewriting.WordRewriter.RewriteConstants C# (CSharp) Method

        private TokenStream RewriteConstants(TokenStream tokens)
        {
            List<Token> result = new List<Token>();
            foreach (Token token in tokens)
            {
                if (token.Type == TokenType.Word)
                {
                    string name = (string)token.Value;
                    if (_constants.ContainsKey(name))
                    {
                        name = name.ToLowerInvariant();
                        double value = _constants[name];
                        result.Add(new Token(TokenType.Constant, new Tuple<string, double>(name, value)));
                        continue;
                    }
                }
                result.Add(token);
            }
            return new TokenStream(result, tokens.Notation);
        }