private SelectColumnBase ParseColumn(List <string> wordList, List <SqlStatementError> errors)
{
var startWord = wordList[0];
var ascTokenIndex = 0;
var descTokenIndex = wordList.Count - 1;
var nextToken = wordList.Count > 1
? wordList[++ascTokenIndex]
: null;
if (nextToken == "(")
{
var functionName = startWord;
var functionLabel = "";
if (wordList[descTokenIndex] == ")")
{
functionLabel = startWord;
descTokenIndex--;
}
else
{
functionLabel = wordList[descTokenIndex];
descTokenIndex--;
if (wordList[descTokenIndex].NotIn(")", "as"))
{
throw new Exception($"Unexpected token after function '{wordList[wordList.Count - 2]}'");
}
if (wordList[descTokenIndex] == "as")
{
descTokenIndex--;
}
if (wordList[descTokenIndex] == ")")
{
descTokenIndex--;
}
}
var functionColumn = new SelectColumnFunction(functionName, functionLabel);
var argList = wordList.GetRange(2, descTokenIndex - 1);
var functionArgs = ParserUtils.SplitTokens(argList);
foreach (var functionArg in functionArgs)
{
functionColumn.Args.Add(ParseColumn(functionArg, errors));
}
return(functionColumn);
}
double number = 0;
SelectColumnBase selectColumn = null;
if (startWord.IsQuoted() || (double.TryParse(startWord, out number)))
{
object value = startWord.IsQuoted()
? startWord.CleanRaw()
: number.ToString();
var valueType = startWord.IsQuoted()
? typeof(string)
: typeof(double);
if (startWord.IsQuoted() == false && startWord.IndexOf(".", StringComparison.Ordinal) < 0)
{
valueType = typeof(int);
value = int.Parse(startWord);
}
if (wordList.Count > 3)
{
errors.Add(new SqlStatementError("Unknown tokens", 0));
return(null);
}
if (wordList.Count == 3)
{
if (wordList[1] != "as")
{
errors.Add(new SqlStatementError("Expecting 'As' keyword", 0));
return(null);
}
selectColumn = new RawSelectColumn(wordList[2], value)
{
ValueType = valueType
};
}
else if (wordList.Count == 2)
{
selectColumn = new RawSelectColumn(wordList[1], value)
{
ValueType = valueType
};
}
else
{
selectColumn = new RawSelectColumn(null, value)
{
ValueType = valueType
};
}
return(selectColumn);
}
if (char.IsLetter(startWord[0]))
{
if (wordList.Count > 3)
{
errors.Add(new SqlStatementError("Unknown tokens", 0));
return(null);
}
if (wordList.Count == 3)
{
if (wordList[1] != "as")
{
errors.Add(new SqlStatementError("Expecting 'As' keyword", 0));
return(null);
}
selectColumn = new FieldSelectColumn(wordList[2], startWord);
}
else if (wordList.Count == 2)
{
selectColumn = new FieldSelectColumn(wordList[1], startWord);
}
else
{
selectColumn = new FieldSelectColumn(null, startWord);
}
return(selectColumn);
}
throw new Exception("Unexpected function arguments.");
}
public TokenParserResults Parse(ParseArgs <SelectStatement> parseArgs)
{
var selectStatement = parseArgs.Statement;
var args = parseArgs.StatementArgs;
var statementParser = parseArgs.StatementsParser;
var results = new TokenParserResults();
var words = ParserUtils.GetWords(args).ToList();
var index = 0;
if (words.Any())
{
if (words[0] == "top")
{
if (words.Count >= 2)
{
var value = 0;
if (int.TryParse(words[1], out value))
{
selectStatement.Top = value;
index = 2;
}
else
{
results.Errors.Add(new SqlStatementError("Top expects a numerical value", 0));
}
}
else
{
results.Errors.Add(new SqlStatementError("Top without a numerical value", 0));
}
}
if (results.Errors.Any())
{
return(results);
}
var columns = ParserUtils.SplitTokens(words.GetRange(index, words.Count - index));
foreach (var wordList in columns)
{
if (wordList.Any() == false)
{
results.Errors.Add(new SqlStatementError("No column specified", 0));
return(results);
}
SelectColumnBase selectColumn = null;
var startWord = wordList[0];
double number = 0;
if (startWord.IsQuoted() || double.TryParse(startWord, out number))
{
object value = startWord.IsQuoted()
? startWord.CleanRaw()
: number.ToString();
var valueType = startWord.IsQuoted()
? typeof(string)
: typeof(double);
if (startWord.IsQuoted() == false && startWord.IndexOf(".", StringComparison.Ordinal) < 0)
{
valueType = typeof(int);
value = int.Parse(startWord);
}
if (wordList.Count > 3)
{
results.Errors.Add(new SqlStatementError("Unknown tokens", 0));
return(results);
}
if (wordList.Count == 3)
{
if (wordList[1] != "as")
{
results.Errors.Add(new SqlStatementError("Expecting 'As' keyword", 0));
return(results);
}
selectColumn = new RawSelectColumn(wordList[2], value)
{
ValueType = valueType
};
}
else if (wordList.Count == 2)
{
selectColumn = new RawSelectColumn(wordList[1], value)
{
ValueType = valueType
};
}
else
{
selectColumn = new RawSelectColumn(null, value)
{
ValueType = valueType
};
}
}
else if (startWord.StartsWith("*"))
{
if (wordList.Count > 1)
{
results.Errors.Add(new SqlStatementError("Found unsupported tokens after '*'", 0));
return(results);
}
selectColumn = new AllSelectColumn();
}
else if (startWord.StartsWith("+"))
{
if (wordList.Count > 1)
{
results.Errors.Add(new SqlStatementError("Found unsupported tokens after '+'", 0));
return(results);
}
selectColumn = new SystemSelectColumn();
}
else if (char.IsLetter(startWord[0]))
{
selectColumn = ParseColumn(wordList, results.Errors);
}
else if (startWord == "(")
{
var nextWord = wordList[1];
if (nextWord == "select")
{
var startIndex = 1;
var endIndex = wordList.FindLastIndex(x => x == ")");
var innerSql = string.Join(" ", wordList.GetRange(startIndex, endIndex - startIndex));
var statement = statementParser.ParseSelect(new SqlStatement()
{
Builder = new StringBuilder(innerSql)
});
if (statement.Errors.Any())
{
throw new Exception($"Unable to parse inner select statement '{innerSql}'");
}
var descTokenIndex = wordList.Count - 1;
var label = wordList[descTokenIndex];
descTokenIndex--;
if (wordList[descTokenIndex].NotIn(")", "as"))
{
throw new Exception($"Unexpected token after inner select '{innerSql}'");
}
if (wordList[descTokenIndex] == "as")
{
descTokenIndex--;
}
if (wordList[descTokenIndex] != ")")
{
throw new Exception($"Unexpected token after inner select '{innerSql}'");
}
selectColumn = new InnerSelectColumn(label, statement.Value);
}
}
if (selectColumn == null)
{
throw new NotSupportedException();
}
selectStatement.Columns.Add(selectColumn);
}
}
return(results);
}
