public static SqlToken MaybeGetKeywordSequence(this ITokenizer ITokenizer, params string[] allowed)
{
var lookup = new HashSet <string>(allowed);
var keywords = new List <SqlToken>();
while (true)
{
var next = ITokenizer.GetNext();
if (!next.IsType(SqlTokenType.Keyword))
{
ITokenizer.PutBack(next);
break;
}
if (!lookup.Contains(next.Value))
{
ITokenizer.PutBack(next);
break;
}
keywords.Add(next);
}
if (!keywords.Any())
{
return(null);
}
var combined = string.Join(" ", keywords.Select(k => k.Value));
return(SqlToken.Keyword(combined, keywords.First().Location));
}
public static SqlToken Peek(this ITokenizer ITokenizer)
{
var t = ITokenizer.GetNext();
ITokenizer.PutBack(t);
return(t);
}
private ISqlNode ParseSelectColumn(ITokenizer t)
{
var next = t.GetNext();
// "*"
if (next.Is(SqlTokenType.Symbol, "*"))
{
return(new SqlOperatorNode(next));
}
// TODO: Should change this to (<Variable> "=")? <SelectColumnExpression>
// <Variable> ("=" <SelectColumnExpression>)?
if (next.IsType(SqlTokenType.Variable))
{
if (t.NextIs(SqlTokenType.Symbol, "="))
{
var equalsOperator = t.GetNext();
var rvalue = ParseScalarExpression(t);
return(new SqlInfixOperationNode
{
Location = equalsOperator.Location,
Left = new SqlVariableNode(next),
Right = rvalue,
Operator = new SqlOperatorNode(equalsOperator)
});
}
}
t.PutBack(next);
// <SelectColumnExpression> (AS <Alias>)?
return(ParseMaybeAliasedScalar(t, ParseSelectColumnExpression));
}
public static bool NextIs(this ITokenizer ITokenizer, SqlTokenType type, string value, bool consume = false)
{
var t = ITokenizer.GetNext();
bool isSame = t.Type == type && t.Value == value;
if (!isSame)
{
ITokenizer.PutBack(t);
return(false);
}
if (!consume)
{
ITokenizer.PutBack(t);
}
return(true);
}
private ISqlNode ParseFunctionCall(ITokenizer t)
{
var name = t.GetNext();
if (name.Type != SqlTokenType.Keyword && name.Type != SqlTokenType.Identifier)
{
throw ParsingException.UnexpectedToken(SqlTokenType.Identifier, name);
}
// "COUNT" "(" "*" ")"
if (name.IsKeyword("COUNT"))
{
var openParen = t.Expect(SqlTokenType.Symbol, "(");
var maybeStar = t.Peek();
if (maybeStar.IsSymbol("*"))
{
t.GetNext();
t.Expect(SqlTokenType.Symbol, ")");
return(new SqlFunctionCallNode
{
Location = name.Location,
Name = new SqlKeywordNode(name),
Arguments = new SqlListNode <ISqlNode> {
new SqlOperatorNode(maybeStar)
}
});
}
// It's not *, so put everything back, fallthrough, and let the rest of the parsing happen
t.PutBack(openParen);
}
// TODO: "CONVERT" "(" <DataType>, <ScalarExpression> ("," <int>)? ")"
// "CAST" "(" <ScalarExpression> "AS" <DataType> ")"
if (name.IsKeyword("CAST"))
{
t.Expect(SqlTokenType.Symbol, "(");
var first = ParseScalarExpression(t);
t.Expect(SqlTokenType.Keyword, "AS");
var type = ParseDataType(t);
t.Expect(SqlTokenType.Symbol, ")");
return(new SqlCastNode
{
Location = name.Location,
Expression = first,
DataType = type
});
}
// <Name> "(" <ScalarExpressionList> ")"
return(new SqlFunctionCallNode
{
Location = name.Location,
Name = Facts.IsBuiltInFunctionName(name.Value) ? (ISqlNode) new SqlKeywordNode(name.Value.ToUpperInvariant(), name.Location) : new SqlIdentifierNode(name),
Arguments = ParseParenthesis(t, x => ParseList(x, ParseScalarExpression)).Expression
});
}
private SqlNumberNode ParseNumber(ITokenizer t)
{
var next = t.GetNext();
if (next.IsType(SqlTokenType.Number))
{
return(new SqlNumberNode(next));
}
t.PutBack(next);
return(null);
}
private ISqlNode ParseVariableOrObjectIdentifier(ITokenizer t)
{
var next = t.GetNext();
// <Variable>
if (next.IsType(SqlTokenType.Variable))
{
return(new SqlVariableNode(next));
}
t.PutBack(next);
return(ParseObjectIdentifier(t));
}
public static void Skip(this ITokenizer ITokenizer, SqlTokenType type)
{
while (true)
{
var t = ITokenizer.GetNext();
if (t.Type == SqlTokenType.EndOfInput || type == SqlTokenType.EndOfInput)
{
break;
}
if (t.Type != type)
{
ITokenizer.PutBack(t);
break;
}
}
}
private ISqlNode ParseVariableOrQualifiedIdentifier(ITokenizer t)
{
var next = t.GetNext();
// <Variable>
if (next.IsType(SqlTokenType.Variable))
{
return(new SqlVariableNode(next));
}
t.PutBack(next);
var identifier = ParseQualifiedIdentifier(t);
if (identifier != null)
{
return(identifier);
}
throw ParsingException.CouldNotParseRule(nameof(ParseVariableOrQualifiedIdentifier), next);
}
private ISqlNode ParseVariableOrConstant(ITokenizer t)
{
var next = t.GetNext();
if (next.IsType(SqlTokenType.Variable))
{
return(new SqlVariableNode(next));
}
if (next.IsType(SqlTokenType.QuotedString))
{
return(new SqlStringNode(next));
}
t.PutBack(next);
var number = ParseNumber(t);
if (number != null)
{
return(number);
}
throw ParsingException.CouldNotParseRule(nameof(ParseVariableOrConstant), next);
}
private ISqlNode ParseScalarExpression0(ITokenizer t)
{
// Terminal expression
// <MethodCall> | <Identifier> | <Variable> | <String> | <Number> | "(" <Expression> ")"
var next = t.Peek();
if (next.IsKeyword("TARGET", "SOURCE"))
{
return(ParseQualifiedIdentifier(t));
}
if (next.IsKeyword("CAST", "CONVERT", "COUNT"))
{
var name = t.GetNext();
if (t.Peek().IsSymbol("("))
{
t.PutBack(name);
return(ParseFunctionCall(t));
}
throw ParsingException.CouldNotParseRule(nameof(ParseScalarExpression0), next);
}
if (next.IsType(SqlTokenType.Identifier))
{
var name = t.GetNext();
if (t.Peek().IsSymbol("("))
{
t.PutBack(name);
return(ParseFunctionCall(t));
}
t.PutBack(name);
return(ParseQualifiedIdentifier(t));
}
if (next.IsType(SqlTokenType.Variable))
{
return(new SqlVariableNode(t.GetNext()));
}
if (next.IsType(SqlTokenType.QuotedString))
{
return(new SqlStringNode(t.GetNext()));
}
if (next.IsType(SqlTokenType.Number))
{
return(new SqlNumberNode(t.GetNext()));
}
if (next.IsSymbol("("))
{
// "(" (<QueryExpression> | <ScalarExpression>) ")"
// e.g. SET @x = (select 5) or INSERT INTO x(num) VALUES (1, 2, (select 3))
var value = ParseParenthesis(t, x =>
{
if (x.Peek().IsKeyword("SELECT"))
{
return(ParseQueryExpression(t));
}
return(ParseScalarExpression(t));
});
if (value.Expression is SqlSelectNode)
{
return(value);
}
return(value.Expression);
}
throw ParsingException.CouldNotParseRule(nameof(ParseScalarExpression0), next);
}
public SqlExecuteArgumentNode ParseExecArgument(ITokenizer t)
{
// (<parameter> "=")? (<Expression> | "DEFAULT" | <Variable> ("OUT"|"OUTPUT"))
var next = t.GetNext();
if (next.IsSymbol(";") || next.IsType(SqlTokenType.EndOfInput))
{
return(null);
}
if (next.IsKeyword("DEFAULT"))
{
var keyword = new SqlKeywordNode(next);
return(new SqlExecuteArgumentNode
{
Location = keyword.Location,
Value = keyword
});
}
if (next.IsType(SqlTokenType.Variable))
{
var lookahead = t.Peek();
if (lookahead.IsSymbol("="))
{
t.GetNext();
return(new SqlExecuteArgumentNode
{
Location = next.Location,
AssignVariable = new SqlVariableNode(next),
Value = ParseScalarExpression(t),
IsOut = t.NextIs(SqlTokenType.Keyword, "OUT", true) || t.NextIs(SqlTokenType.Keyword, "OUTPUT", true)
});
}
}
ISqlNode expression = null;
if (next.IsType(SqlTokenType.Identifier, SqlTokenType.Number, SqlTokenType.QuotedString, SqlTokenType.Variable))
{
t.PutBack(next);
expression = ParseScalarExpression(t);
}
else if (next.IsType(SqlTokenType.Keyword))
{
if (t.Peek().IsSymbol("("))
{
t.PutBack(next);
expression = ParseScalarExpression(t);
}
}
if (expression == null)
{
t.PutBack(next);
return(null);
}
return(new SqlExecuteArgumentNode
{
Location = next.Location,
Value = expression,
IsOut = t.NextIs(SqlTokenType.Keyword, "OUT", true) || t.NextIs(SqlTokenType.Keyword, "OUTPUT", true)
});
}
private ISqlNode ParseUnterminatedStatement(ITokenizer t)
{
t.Skip(SqlTokenType.Whitespace);
var keyword = t.Peek();
if (keyword.Type == SqlTokenType.Keyword)
{
if (keyword.Value == "SELECT")
{
return(ParseQueryExpression(t));
}
if (keyword.Value == "WITH")
{
return(ParseWithStatement(t));
}
if (keyword.Value == "INSERT")
{
return(ParseInsertStatement(t));
}
if (keyword.Value == "UPDATE")
{
return(ParseUpdateStatement(t));
}
if (keyword.Value == "DELETE")
{
return(ParseDeleteStatement(t));
}
if (keyword.Value == "DECLARE")
{
return(ParseDeclare(t));
}
if (keyword.Value == "EXEC" || keyword.Value == "EXECUTE")
{
return(ParseExecute(t));
}
if (keyword.Value == "BEGIN")
{
return(ParseBeginEndStatementList(t));
}
if (keyword.Value == "IF")
{
return(ParseIf(t));
}
if (keyword.Value == "MERGE")
{
return(ParseMergeStatement(t));
}
}
if (keyword.Type == SqlTokenType.Identifier || keyword.Type == SqlTokenType.Variable)
{
var id = t.GetNext();
var op = t.Peek();
t.PutBack(id);
if (op.IsSymbol(":="))
{
return(ParseSet(t));
}
}
// TODO: RETURN?
// TODO: THROW/TRY/CATCH
// TODO: WHILE/CONTINUE/BREAK
// TODO: CREATE/DROP/ALTER? Do we want to handle DDL statments here?
return(null);
}
private SqlOperatorNode ParseJoinOperator(ITokenizer t)
{
// "CROSS" ("APPLY" | "JOIN")
// "NATURAL" "JOIN"
// "INNER" "JOIN"
// ("LEFT" | "RIGHT")? "OUTER"? "JOIN"
var k = t.GetNext();
if (!k.IsKeyword())
{
t.PutBack(k);
return(null);
}
if (k.Value == "CROSS")
{
if (t.NextIs(SqlTokenType.Keyword, "APPLY", true))
{
return(new SqlOperatorNode("CROSS APPLY", k.Location));
}
if (t.NextIs(SqlTokenType.Keyword, "JOIN", true))
{
return(new SqlOperatorNode("CROSS JOIN", k.Location));
}
throw ParsingException.CouldNotParseRule(nameof(ParseJoinOperator), k);
}
if (k.Value == "NATURAL")
{
t.Expect(SqlTokenType.Keyword, "JOIN");
return(new SqlOperatorNode("NATURAL JOIN", k.Location));
}
if (k.Value == "INNER")
{
t.Expect(SqlTokenType.Keyword, "JOIN");
return(new SqlOperatorNode("INNER JOIN", k.Location));
}
var joinOperator = new List <SqlToken>();
var location = k.Location;
if (k.Value == "FULL" || k.Value == "LEFT" || k.Value == "RIGHT")
{
joinOperator.Add(k);
k = t.GetNext();
}
if (k.Value == "OUTER")
{
joinOperator.Add(k);
k = t.GetNext();
if (k.Value == "APPLY")
{
return(new SqlOperatorNode("OUTER APPLY"));
}
}
// TODO: hints: "MERGE" | "HASH" | "REDISTRIBUTE" | "REPLICATE" | "REDUCE"
if (k.Value == "JOIN")
{
joinOperator.Add(k);
var op = string.Join(" ", joinOperator.Select(j => j.Value));
return(new SqlOperatorNode(op, location));
}
if (joinOperator.Count > 0)
{
throw ParsingException.CouldNotParseRule(nameof(ParseJoinOperator), k);
}
t.PutBack(k);
return(null);
}