private SqlOrderByEntryNode ParseOrderTerm(ITokenizer t)
{
// ( <QualifiedIdentifier> | <Number> ) ("ASC" | "DESC")?
var identifier = ParseQualifiedIdentifier(t);
if (identifier == null)
{
if (t.Peek().IsType(SqlTokenType.Number))
{
var number = t.GetNext();
identifier = new SqlNumberNode(number);
}
}
if (identifier == null)
{
throw ParsingException.CouldNotParseRule(nameof(ParseOrderTerm), t.Peek());
}
var entry = new SqlOrderByEntryNode
{
Location = identifier.Location,
Source = identifier
};
var next = t.Peek();
if (next.IsKeyword("ASC") || next.IsKeyword("DESC"))
{
t.GetNext();
entry.Direction = next.Value;
}
return(entry);
}
private ISqlNode ParseMaybeAliasedScalar(ITokenizer t, Func <ITokenizer, ISqlNode> parse)
{
var node = parse(t);
var next = t.Peek();
if (next.IsKeyword("AS"))
{
var asToken = t.GetNext();
var alias = t.Expect(SqlTokenType.Identifier);
return(new SqlAliasNode
{
Location = asToken.Location,
Source = node,
Alias = new SqlIdentifierNode(alias)
});
}
if (next.IsType(SqlTokenType.Identifier))
{
t.GetNext();
return(new SqlAliasNode
{
Location = node.Location,
Source = node,
Alias = new SqlIdentifierNode(next)
});
}
return(node);
}
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));
}
private ISqlNode ParseInsertOnConflictClause(ITokenizer t)
{
if (!t.Peek().IsKeyword("ON"))
{
return(null);
}
t.GetNext();
t.Expect(SqlTokenType.Keyword, "CONFLICT");
t.Expect(SqlTokenType.Keyword, "DO");
var next = t.Peek();
if (next.IsKeyword("NOTHING"))
{
return(new SqlKeywordNode(t.GetNext()));
}
if (next.IsKeyword("UPDATE"))
{
var updateToken = t.Expect(SqlTokenType.Keyword, "UPDATE");
return(new SqlUpdateNode
{
Location = updateToken.Location,
SetClause = ParseUpdateSetClause(t),
WhereClause = ParseWhereClause(t)
});
}
throw new ParsingException("Cannot parse INSERT ... ON CONFLICT clause. Unexpected token " + next);
}
private ISqlNode ParseQualifiedIdentifier(ITokenizer t)
{
// ( <Qualifier> "." )? <Identifier>
var next = t.Peek();
if (!next.IsType(SqlTokenType.Identifier) && !next.IsType(SqlTokenType.Keyword))
{
return(null);
}
t.GetNext();
if (!t.Peek().Is(SqlTokenType.Symbol, "."))
{
return(new SqlIdentifierNode(next));
}
t.GetNext();
var qualifier = new SqlIdentifierNode(next);
var identifier = t.GetNext();
return(new SqlQualifiedIdentifierNode
{
Location = qualifier.Location,
Qualifier = qualifier,
Identifier = identifier.Is(SqlTokenType.Symbol, "*") ? (ISqlNode) new SqlOperatorNode("*") : new SqlIdentifierNode(identifier)
});
}
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 ISqlNode ParseTableOrSubexpression(ITokenizer t)
{
// <ObjectIdentifier> | <tableVariable> | "(" <QueryExpression> ")" | "(" <ValuesExpression> ")"
var lookahead = t.Peek();
// <ObjectIdentifier>
if (lookahead.IsType(SqlTokenType.Identifier))
{
return(ParseObjectIdentifier(t));
}
// <tableVariable>
if (lookahead.IsType(SqlTokenType.Variable))
{
return(new SqlVariableNode(t.GetNext()));
}
// "(" <Subexpression> ")"
if (lookahead.Is(SqlTokenType.Symbol, "("))
{
return(ParseParenthesis(t, ParseSubexpression));
}
throw ParsingException.CouldNotParseRule(nameof(ParseTableOrSubexpression), lookahead);
}
private ISqlNode ParseQuerySpecificiation(ITokenizer t)
{
// "SELECT" ...
var selectToken = t.Expect(SqlTokenType.Keyword, "SELECT");
var selectNode = new SqlSelectNode
{
Location = selectToken.Location
};
var modifier = t.Peek();
if (modifier.IsKeyword("ALL") || modifier.IsKeyword("DISTINCT"))
{
t.GetNext();
selectNode.Modifier = modifier.Value;
}
selectNode.Columns = ParseList(t, ParseSelectColumn);
selectNode.FromClause = ParseSelectFromClause(t);
selectNode.WhereClause = ParseWhereClause(t);
selectNode.GroupByClause = ParseSelectGroupByClause(t);
selectNode.HavingClause = ParseSelectHavingClause(t);
selectNode.OrderByClause = ParseSelectOrderByClause(t);
selectNode.TopLimitClause = ParseSelectLimitClause(t);
selectNode.OffsetClause = ParseSelectOffsetClause(t);
selectNode.FetchClause = ParseSelectFetchClause(t);
return(selectNode);
}
private SqlTopLimitNode ParseSelectTopClause(ITokenizer t)
{
// "TOP" "(" <Number> | <Variable> ")" "PERCENT"? "WITH TIES"?
// "TOP" <Number> | <Variable> "PERCENT"? "WITH TIES"?
if (!t.NextIs(SqlTokenType.Keyword, "TOP"))
{
return(null);
}
var topToken = t.GetNext();
var numberOrVariable = ParseMaybeParenthesis(t, ParseNumberOrVariable);
bool percent = t.NextIs(SqlTokenType.Keyword, "PERCENT", true);
bool withTies = false;
if (t.NextIs(SqlTokenType.Keyword, "WITH", true))
{
t.Expect(SqlTokenType.Keyword, "TIES");
withTies = true;
}
return(new SqlTopLimitNode {
Location = topToken.Location,
Value = numberOrVariable,
Percent = percent,
WithTies = withTies
});
}
private SqlStatementListNode ParseBeginEndStatementList(ITokenizer t)
{
t.Expect(SqlTokenType.Keyword, "BEGIN");
var statements = new SqlStatementListNode {
UseBeginEnd = true
};
while (true)
{
var lookahead = t.Peek();
if (lookahead.IsType(SqlTokenType.EndOfInput))
{
throw ParsingException.CouldNotParseRule(nameof(ParseBeginEndStatementList), lookahead);
}
if (lookahead.Is(SqlTokenType.Keyword, "END"))
{
t.GetNext();
break;
}
var statement = ParseStatement(t);
if (statement == null)
{
throw ParsingException.CouldNotParseRule(nameof(ParseBeginEndStatementList), t.Peek());
}
statements.Statements.Add(statement);
}
return(statements);
}
public static SqlToken Peek(this ITokenizer ITokenizer)
{
var t = ITokenizer.GetNext();
ITokenizer.PutBack(t);
return(t);
}
public SqlInsertNode ParseMergeNotMatched(ITokenizer t)
{
var insertToken = t.Expect(SqlTokenType.Keyword, "INSERT");
var insertNode = new SqlInsertNode
{
Location = insertToken.Location,
Columns = ParseInsertColumnList(t)
};
var next = t.Peek();
if (next.IsKeyword("VALUES"))
{
insertNode.Source = ParseValues(t);
}
else if (next.IsKeyword("DEFAULT"))
{
t.GetNext();
t.Expect(SqlTokenType.Keyword, "VALUES");
insertNode.Source = new SqlKeywordNode("DEFAULT VALUES");
}
else
{
throw new ParsingException("INSERT statement does not have a source");
}
return(insertNode);
}
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));
}
private SqlInfixOperationNode ParseUpdateColumnAssignExpression(ITokenizer t)
{
// (<Column> | <Variable>) <CompareOp> ("DEFAULT" | <Expression>)
var columnName = ParseVariableOrQualifiedIdentifier(t);
// TODO: Other assignment operators
var opToken = t.Expect(SqlTokenType.Symbol, "=", "+=", "-=", "*=", "/=", "%=", "&=", "^=", "|=");
ISqlNode rvalue;
var lookahead = t.Peek();
if (lookahead.Is(SqlTokenType.Keyword, "DEFAULT"))
{
t.GetNext();
rvalue = new SqlKeywordNode(lookahead);
}
else
{
rvalue = ParseScalarExpression(t);
}
return(new SqlInfixOperationNode
{
Left = columnName,
Location = columnName.Location,
Operator = new SqlOperatorNode(opToken),
Right = rvalue
});
}
private ISqlNode ParseCaseExpression(ITokenizer t)
{
// "CASE" <Expression>? <When>+ <Else>? "END"
var caseToken = t.Expect(SqlTokenType.Keyword, "CASE");
var caseNode = new SqlCaseNode
{
Location = caseToken.Location
};
if (!t.Peek().IsKeyword("WHEN"))
{
caseNode.InputExpression = ParseScalarExpression(t);
}
while (true)
{
var lookahead = t.Peek();
if (lookahead.IsKeyword("END"))
{
t.GetNext();
return(caseNode);
}
if (lookahead.IsKeyword("ELSE"))
{
t.GetNext();
caseNode.ElseExpression = ParseScalarExpression(t);
t.Expect(SqlTokenType.Keyword, "END");
return(caseNode);
}
if (lookahead.IsKeyword("WHEN"))
{
var whenNode = t.GetNext();
var condition = ParseBooleanExpression(t);
t.Expect(SqlTokenType.Keyword, "THEN");
var result = ParseScalarExpression(t);
caseNode.WhenExpressions.Add(new SqlCaseWhenNode
{
Location = whenNode.Location,
Condition = condition,
Result = result
});
continue;
}
throw ParsingException.CouldNotParseRule(nameof(ParseCaseExpression), lookahead);
}
}
public static SqlToken GetIdentifierOrKeyword(this ITokenizer ITokenizer)
{
var next = ITokenizer.GetNext();
if (next.IsType(SqlTokenType.Identifier) || next.IsType(SqlTokenType.Keyword))
{
return(next);
}
throw ParsingException.UnexpectedToken(SqlTokenType.Identifier, next);
}
private ISqlNode ParseSelectFromClause(ITokenizer t)
{
// ("FROM" <join>)?
if (!t.NextIs(SqlTokenType.Keyword, "FROM"))
{
return(null);
}
t.GetNext();
return(ParseJoin(t));
}
public static SqlToken Expect(this ITokenizer ITokenizer, SqlTokenType type)
{
var found = ITokenizer.GetNext();
if (found.Type != type)
{
throw ParsingException.UnexpectedToken(type, found);
}
return(found);
}
private ISqlNode ParseSelectHavingClause(ITokenizer t)
{
// "HAVING" <BooleanExpression>
if (!t.NextIs(SqlTokenType.Keyword, "HAVING"))
{
return(null);
}
t.GetNext();
return(ParseBooleanExpression(t));
}
private ISqlNode ParseWhereClause(ITokenizer t)
{
// "WHERE" <BooleanExpression>
if (!t.NextIs(SqlTokenType.Keyword, "WHERE"))
{
return(null);
}
t.GetNext();
return(ParseBooleanExpression(t));
}
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 ParseSelectGroupByClause(ITokenizer t)
{
// "GROUP" "BY" <IdentifierList>
if (!t.NextIs(SqlTokenType.Keyword, "GROUP"))
{
return(null);
}
t.GetNext();
t.Expect(SqlTokenType.Keyword, "BY");
return(ParseList(t, ParseQualifiedIdentifier));
}
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));
}
private ISqlNode ParseSelectOffsetClause(ITokenizer t)
{
if (!t.NextIs(SqlTokenType.Keyword, "OFFSET"))
{
return(null);
}
t.GetNext();
var offset = ParseNumberOrVariable(t);
t.Expect(SqlTokenType.Keyword, "ROW", "ROWS");
return(offset);
}
private SqlDataTypeNode ParseDataType(ITokenizer t)
{
// <Keyword> ("(" ("MAX" | <SizeList>)? ")")?
var next = t.GetNext();
// TODO: Array types
// TODO: Should we add TABLE declaration parsing?
if (next.IsKeyword("TABLE"))
{
return(null);
}
var dataType = new SqlDataTypeNode
{
Location = next.Location,
DataType = new SqlKeywordNode(next),
};
if (t.Peek().IsSymbol("("))
{
t.GetNext();
var lookahead = t.Peek();
if (lookahead.IsKeyword("MAX"))
{
dataType.Size = new SqlKeywordNode(t.GetNext());
}
else if (lookahead.IsType(SqlTokenType.Number))
{
dataType.Size = ParseList(t, ParseNumber);
}
else
{
throw ParsingException.CouldNotParseRule(nameof(ParseDataType), lookahead);
}
t.Expect(SqlTokenType.Symbol, ")");
}
return(dataType);
}
private ISqlNode ParseMaybeAliasedTable(ITokenizer t, Func <ITokenizer, ISqlNode> parse)
{
var node = parse(t);
var next = t.Peek();
SqlToken aliasToken = null;
Location location = null;
if (next.IsKeyword("AS"))
{
location = t.GetNext().Location;
aliasToken = t.GetIdentifierOrKeyword();
}
else if (next.IsType(SqlTokenType.Identifier))
{
aliasToken = t.GetNext();
}
if (aliasToken == null)
{
return(node);
}
var alias = new SqlAliasNode
{
Location = location ?? aliasToken.Location,
Source = node,
Alias = new SqlIdentifierNode(aliasToken)
};
if (t.Peek().IsSymbol("("))
{
alias.ColumnNames = ParseParenthesis(t, x => ParseList(x, ParseIdentifier)).Expression;
}
return(alias);
}
private ISqlNode ParseNumberOrVariable(ITokenizer t)
{
var next = t.GetNext();
if (next.IsType(SqlTokenType.Variable))
{
return(new SqlVariableNode(next));
}
if (next.IsType(SqlTokenType.Number))
{
return(new SqlNumberNode(next));
}
throw ParsingException.CouldNotParseRule(nameof(ParseNumberOrVariable), next);
}
private ISqlNode ParseSelectFetchClause(ITokenizer t)
{
if (!t.NextIs(SqlTokenType.Keyword, "FETCH"))
{
return(null);
}
t.GetNext();
t.Expect(SqlTokenType.Keyword, "FIRST", "NEXT");
var fetch = ParseNumberOrVariable(t);
t.Expect(SqlTokenType.Keyword, "ROW", "ROWS");
t.Expect(SqlTokenType.Keyword, "ONLY");
return(fetch);
}
private ISqlNode ParseScalarExpression1(ITokenizer t)
{
// "NULL" | ("-" | "+" | "~") <Expression0> | <Expression0>
var next = t.Peek();
if (next.IsKeyword("NULL"))
{
var nullToken = t.GetNext();
return(new SqlNullNode(nullToken));
}
if (next.IsSymbol("-", "+", "~"))
{
var op = t.GetNext();
var expr = ParseScalarExpression1(t);
return(new SqlPrefixOperationNode
{
Location = op.Location,
Operator = new SqlOperatorNode(op),
Right = expr
});
}
return(ParseScalarExpression0(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;
}
}
}