private Yytoken[] Lex(string value)
{
ArrayList tokens = new ArrayList();
using (StringReader reader = new StringReader(value))
{
OPathLexer lexer = new OPathLexer(reader);
Yytoken token;
while ((token = lexer.Lex()) != null)
{
tokens.Add(token);
}
}
return((Yytoken[])tokens.ToArray(typeof(Yytoken)));
}
public OrderBy Parse(Type type, string expression)
{
// Example expressions for an Employee query:
// "FirstName, LastName"
// "FirstName ASC, LastName DESC"
// "Company.Name"
// "Company.Name ASC"
// "Company.Address.State ASC"
// "Company.Name ASC, Company.Address.State ASC, FirstName ASC"
// "Company.Name ASC, HomeAddress.ZipCode, Company.Address.State DESC, ZipCode"
_expression = expression;
EntityMap entity = _maps[type];
if (entity == null)
{
throw new Exception("Type " + type + " does not have an entity mapping defined to the database.");
}
OrderByItemCollection items = new OrderByItemCollection();
OrderByJoinCollection joins = new OrderByJoinCollection();
using (StringReader reader = new StringReader(expression))
{
OPathLexer lexer = new OPathLexer(reader);
lexer.Lex();
while (lexer.CurrentToken != null)
{
OrderByItem item = ParseItem(lexer, entity, joins, null);
items.Add(item);
}
if (lexer.LastToken != null && lexer.LastToken.Type == TokenType.COMMA)
{
throw new OPathException("A trailing comma was detected in sort expression '" + expression + "'.");
}
}
return(new OrderBy(null, items, joins));
}
public OrderBy Parse(Type type, string expression)
{
// Example expressions for an Employee query:
// "FirstName, LastName"
// "FirstName ASC, LastName DESC"
// "Company.Name"
// "Company.Name ASC"
// "Company.Address.State ASC"
// "Company.Name ASC, Company.Address.State ASC, FirstName ASC"
// "Company.Name ASC, HomeAddress.ZipCode, Company.Address.State DESC, ZipCode"
_expression = expression;
EntityMap entity = _maps[type];
if( entity == null )
{
throw new Exception("Type " + type + " does not have an entity mapping defined to the database.");
}
OrderByItemCollection items = new OrderByItemCollection();
OrderByJoinCollection joins = new OrderByJoinCollection();
using( StringReader reader = new StringReader(expression) )
{
OPathLexer lexer = new OPathLexer(reader);
lexer.Lex();
while( lexer.CurrentToken != null )
{
OrderByItem item = ParseItem(lexer, entity, joins, null);
items.Add(item);
}
if( lexer.LastToken != null && lexer.LastToken.Type == TokenType.COMMA )
{
throw new OPathException("A trailing comma was detected in sort expression '" + expression + "'.");
}
}
return new OrderBy(null, items, joins);
}
private OrderByItem ParseItem(OPathLexer lexer, EntityMap entity, OrderByJoinCollection joins, OrderByJoin parentJoin)
{
Yytoken token = lexer.CurrentToken;
if (token.Type != TokenType.IDENT)
{
throw new OPathException("'" + token.Text + "' encountered where a property or relationship was expected in sort expression '" + _expression + "'.");
}
string propertyName = token.Text;
token = lexer.Lex();
if (token == null)
{
FieldMap field;
try
{
field = entity.GetFieldMap(propertyName);
}
catch
{
throw new OPathException(string.Format("The specified property '{0}' in the sort '{1}' is not defined in the entity map for type '{2}'.", propertyName, _expression, entity.Type));
}
return(new OrderByItem(propertyName, field, true, parentJoin));
}
if (token.Type != TokenType.PERIOD)
{
if (token.Type != TokenType.ASCEND && token.Type != TokenType.DESCEND && token.Type != TokenType.COMMA)
{
throw new OPathException("'" + token.Text + "' is not valid in sort expression '" + _expression + "'.");
}
FieldMap field;
try
{
field = entity.GetFieldMap(propertyName);
}
catch
{
throw new OPathException(string.Format("The specified property '{0}' in the sort '{1}' is not defined in the entity map for type '{2}'.", propertyName, _expression, entity.Type));
}
bool ascending = (token.Type != TokenType.DESCEND);
if (token.Type != TokenType.COMMA)
{
lexer.MoveToNext();
}
lexer.MoveToNext();
return(new OrderByItem(propertyName, field, ascending, parentJoin));
}
else // dot operator (.)
{
token = lexer.Lex();
if (token == null)
{
throw new OPathException("End of expression encountered where a property or relationship was expected in sort expression '" + _expression + "'.");
}
if (token.Type != TokenType.IDENT)
{
throw new OPathException("'" + token.Text + "' encountered where a property or relationship was expected in sort expression '" + _expression + "'.");
}
RelationMap relation = entity.Relation(propertyName);
if (relation == null)
{
throw new OPathException(string.Format("The specified relationship '{0}' in the sort expression '{1}' is not defined in the entity map for type '{2}'.", propertyName, _expression, entity.Type));
}
if (relation.Relationship != Relationship.Parent)
{
throw new Exception("Relationship '" + relation.Alias + "' is not a ManyToOne relation. Only ManyToOne relations are allowed in sort expressions.");
}
EntityMap relEntity = _maps[relation.Type];
OrderByJoin join = joins[propertyName];
if (join == null)
{
join = new OrderByJoin(relation);
joins.Add(join);
}
// recursive call
return(ParseItem(lexer, relEntity, join.NestedJoins, join));
}
}
public Expression Parse(string expression)
{
// reset our member vars
_args.Clear();
_ops.Clear();
_parameterCount = 0;
if (expression == null)
{
expression = string.Empty;
}
using (StringReader reader = new StringReader(expression))
{
OPathLexer lexer = new OPathLexer(reader);
Yytoken token;
while ((token = lexer.Lex()) != null)
{
#if DEBUG_PARSER
Debug.WriteLine("----------------------------------------");
DumpStacks("Starting Token: " + token.ToString());
#endif
ProcessToken(token, lexer);
#if DEBUG_PARSER
Debug.WriteLine("----------------------------------------\n");
Debug.WriteLine("");
#endif
}
}
#if DEBUG_PARSER
Debug.WriteLine("----------------------------------------");
Debug.WriteLine("Starting Final Reduction");
#endif
// see if we have a empty expression
if (_args.Count == 0)
{
return(new Empty());
}
// reduce remaining operators on the stack
while (_ops.Count > 0)
{
Reduce(); // reduce the stacks
}
#if DEBUG_PARSER
Debug.WriteLine("----------------------------------------");
Debug.WriteLine("");
#endif
// expression better be completely reduced
if (_args.Count > 1)
{
throw new OPathException("Expression is not valid.");
}
// return root of the tree
return((Expression)_args.Pop());
}
private void ProcessToken(Yytoken token, OPathLexer lexer)
{
switch (token.Type)
{
case TokenType.IDENT:
{
Property node = new Property(token.Text, new Context());
_args.Push(node);
break;
}
case TokenType.PARENT:
{
if (lexer.NextToken == null || lexer.NextToken.Type != TokenType.PERIOD)
{
throw new OPathException("Position " + token.Position + ": Parent relationship operator must be followed by a dot operator.");
}
Parent node = new Parent(new Context());
_args.Push(node);
break;
}
case TokenType.PARAM:
{
Parameter node = new Parameter(_parameterCount);
_parameterCount += 1;
_args.Push(node);
break;
}
case TokenType.CONST:
{
Literal node = new Literal(token.Value);
_args.Push(node);
break;
}
case TokenType.PERIOD:
{
Yytoken last = lexer.LastToken;
Yytoken next = lexer.NextToken;
if (last == null || next == null)
{
throw new OPathException("Position " + token.Position + ": The dot operator (.) cannot be at the very beginning or end of an expression.");
}
// dot operator not valid unless it follows a property/relationship identifier, parent operator, or filter
if (last.Type != TokenType.IDENT && last.Type != TokenType.PARENT && last.Type != TokenType.RBRACE)
{
throw new OPathException("Position " + token.Position + ": Dot operators cannot be used in this way.");
}
// parent operator cannot be after a property/relationship identifer
if (next.Type == TokenType.PARENT && last.Type != TokenType.PARENT)
{
throw new OPathException("Position " + token.Position + ": Parent relationship operators (^) cannot be used in this way.");
}
goto case TokenType.MODULO;
}
case TokenType.MINUS:
{
// change the token to a negation unless followed by a token that supports subtraction
Yytoken last = lexer.LastToken;
if (last == null || (last.Type != TokenType.CONST && last.Type != TokenType.IDENT && last.Type != TokenType.PARAM && last.Type != TokenType.RPAREN))
{
token.Type = TokenType.NEGATE;
}
goto case TokenType.COMMA;
}
case TokenType.COMMA:
case TokenType.OP_EQ:
case TokenType.OP_NE:
case TokenType.OP_GT:
case TokenType.OP_GE:
case TokenType.OP_LT:
case TokenType.OP_LE:
case TokenType.OP_LIKE:
case TokenType.AND:
case TokenType.OR:
case TokenType.NOT:
case TokenType.PLUS:
case TokenType.MULTIPLY:
case TokenType.DIVIDE:
case TokenType.MODULO:
{
if (_ops.Count == 0 || ComparePrecedence(token, (Yytoken)_ops.Peek()) > 0) // new token has higher precedence
{
_ops.Push(token);
}
else // new token has lower or same precedence
{
Reduce();
// process this token again
ProcessToken(token, lexer); // note: recursive call
}
break;
}
case TokenType.OP_IN:
case TokenType.FN_ISNULL:
case TokenType.FN_LEN:
case TokenType.FN_TRIM:
case TokenType.FN_LEFT:
case TokenType.FN_RIGHT:
case TokenType.FN_SUBSTR:
case TokenType.FN_UPPER:
case TokenType.FN_LOWER:
case TokenType.FN_EXISTS:
{
Yytoken nextToken = lexer.Lex();
if (nextToken.Type != TokenType.LPAREN)
{
throw new OPathException("Function '" + token.Text + "' must be followed by an opening parenthesis.");
}
_ops.Push(nextToken);
_ops.Push(token);
break;
}
case TokenType.LPAREN:
case TokenType.LBRACE:
{
_ops.Push(token);
break;
}
case TokenType.RPAREN:
{
if (_ops.Count == 0)
{
throw new OPathException("Closing parenthesis encountered without matching opening parenthesis.");
}
if (((Yytoken)_ops.Peek()).Type == TokenType.LPAREN)
{
_ops.Pop(); // "cancel" the operator pair
}
else
{
Reduce();
// process this token again
ProcessToken(token, lexer); // note: recursive call
}
break;
}
case TokenType.RBRACE:
{
if (_ops.Count == 0)
{
throw new OPathException("Closing brace encountered without matching opening brace.");
}
if (((Yytoken)_ops.Peek()).Type == TokenType.LBRACE)
{
Reduce(); // a final reduce to "cancel" the pair
}
else
{
Reduce();
// process this token again
ProcessToken(token, lexer); // note: recursive call
}
break;
}
default:
{
throw new NotSupportedException("Token type " + token.Type + " at position " + token.Position + " in expression is not supported.");
}
}
#if DEBUG_PARSER
DumpStacks("\nAfter Token: " + token.ToString());
#endif
}
private Yytoken[] Lex(string value)
{
ArrayList tokens = new ArrayList();
using( StringReader reader = new StringReader(value) )
{
OPathLexer lexer = new OPathLexer(reader);
Yytoken token;
while( (token = lexer.Lex()) != null )
{
tokens.Add(token);
}
}
return (Yytoken[])tokens.ToArray(typeof(Yytoken));
}
private OrderByItem ParseItem(OPathLexer lexer, EntityMap entity, OrderByJoinCollection joins, OrderByJoin parentJoin)
{
Yytoken token = lexer.CurrentToken;
if( token.Type != TokenType.IDENT )
{
throw new OPathException("'" + token.Text + "' encountered where a property or relationship was expected in sort expression '" + _expression + "'.");
}
string propertyName = token.Text;
token = lexer.Lex();
if( token == null )
{
FieldMap field;
try
{
field = entity.GetFieldMap(propertyName);
}
catch
{
throw new OPathException(string.Format("The specified property '{0}' in the sort '{1}' is not defined in the entity map for type '{2}'.", propertyName, _expression, entity.Type));
}
return new OrderByItem(propertyName, field, true, parentJoin);
}
if( token.Type != TokenType.PERIOD )
{
if( token.Type != TokenType.ASCEND && token.Type != TokenType.DESCEND && token.Type != TokenType.COMMA )
{
throw new OPathException("'" + token.Text + "' is not valid in sort expression '" + _expression + "'.");
}
FieldMap field;
try
{
field = entity.GetFieldMap(propertyName);
}
catch
{
throw new OPathException(string.Format("The specified property '{0}' in the sort '{1}' is not defined in the entity map for type '{2}'.", propertyName, _expression, entity.Type));
}
bool ascending = (token.Type != TokenType.DESCEND);
if( token.Type != TokenType.COMMA )
{
lexer.MoveToNext();
}
lexer.MoveToNext();
return new OrderByItem(propertyName, field, ascending, parentJoin);
}
else // dot operator (.)
{
token = lexer.Lex();
if( token == null )
{
throw new OPathException("End of expression encountered where a property or relationship was expected in sort expression '" + _expression + "'.");
}
if( token.Type != TokenType.IDENT )
{
throw new OPathException("'" + token.Text + "' encountered where a property or relationship was expected in sort expression '" + _expression + "'.");
}
RelationMap relation = entity.Relation(propertyName);
if( relation == null )
{
throw new OPathException(string.Format("The specified relationship '{0}' in the sort expression '{1}' is not defined in the entity map for type '{2}'.", propertyName, _expression, entity.Type));
}
if( relation.Relationship != Relationship.Parent )
{
throw new Exception("Relationship '" + relation.Alias + "' is not a ManyToOne relation. Only ManyToOne relations are allowed in sort expressions.");
}
EntityMap relEntity = _maps[relation.Type];
OrderByJoin join = joins[propertyName];
if( join == null )
{
join = new OrderByJoin(relation);
joins.Add(join);
}
// recursive call
return ParseItem(lexer, relEntity, join.NestedJoins, join);
}
}
public Expression Parse(string expression)
{
// reset our member vars
_args.Clear();
_ops.Clear();
_parameterCount = 0;
if( expression == null )
{
expression = string.Empty;
}
using( StringReader reader = new StringReader(expression) )
{
OPathLexer lexer = new OPathLexer(reader);
Yytoken token;
while( (token = lexer.Lex()) != null )
{
#if DEBUG_PARSER
Debug.WriteLine("----------------------------------------");
DumpStacks("Starting Token: " + token.ToString());
#endif
ProcessToken(token, lexer);
#if DEBUG_PARSER
Debug.WriteLine("----------------------------------------\n");
Debug.WriteLine("");
#endif
}
}
#if DEBUG_PARSER
Debug.WriteLine("----------------------------------------");
Debug.WriteLine("Starting Final Reduction");
#endif
// see if we have a empty expression
if( _args.Count == 0 )
{
return new Empty();
}
// reduce remaining operators on the stack
while( _ops.Count > 0 )
{
Reduce(); // reduce the stacks
}
#if DEBUG_PARSER
Debug.WriteLine("----------------------------------------");
Debug.WriteLine("");
#endif
// expression better be completely reduced
if( _args.Count > 1 )
{
throw new OPathException("Expression is not valid.");
}
// return root of the tree
return (Expression)_args.Pop();
}
private void ProcessToken(Yytoken token, OPathLexer lexer)
{
switch( token.Type )
{
case TokenType.IDENT:
{
Property node = new Property(token.Text, new Context());
_args.Push(node);
break;
}
case TokenType.PARENT:
{
if( lexer.NextToken == null || lexer.NextToken.Type != TokenType.PERIOD )
{
throw new OPathException("Position " + token.Position + ": Parent relationship operator must be followed by a dot operator.");
}
Parent node = new Parent(new Context());
_args.Push(node);
break;
}
case TokenType.PARAM:
{
Parameter node = new Parameter(_parameterCount);
_parameterCount += 1;
_args.Push(node);
break;
}
case TokenType.CONST:
{
Literal node = new Literal(token.Value);
_args.Push(node);
break;
}
case TokenType.PERIOD:
{
Yytoken last = lexer.LastToken;
Yytoken next = lexer.NextToken;
if( last == null || next == null )
{
throw new OPathException("Position " + token.Position + ": The dot operator (.) cannot be at the very beginning or end of an expression.");
}
// dot operator not valid unless it follows a property/relationship identifier, parent operator, or filter
if( last.Type != TokenType.IDENT && last.Type != TokenType.PARENT && last.Type != TokenType.RBRACE )
{
throw new OPathException("Position " + token.Position + ": Dot operators cannot be used in this way.");
}
// parent operator cannot be after a property/relationship identifer
if( next.Type == TokenType.PARENT && last.Type != TokenType.PARENT )
{
throw new OPathException("Position " + token.Position + ": Parent relationship operators (^) cannot be used in this way.");
}
goto case TokenType.MODULO;
}
case TokenType.MINUS:
{
// change the token to a negation unless followed by a token that supports subtraction
Yytoken last = lexer.LastToken;
if( last == null || (last.Type != TokenType.CONST && last.Type != TokenType.IDENT && last.Type != TokenType.PARAM && last.Type != TokenType.RPAREN) )
{
token.Type = TokenType.NEGATE;
}
goto case TokenType.COMMA;
}
case TokenType.COMMA:
case TokenType.OP_EQ:
case TokenType.OP_NE:
case TokenType.OP_GT:
case TokenType.OP_GE:
case TokenType.OP_LT:
case TokenType.OP_LE:
case TokenType.OP_LIKE:
case TokenType.AND:
case TokenType.OR:
case TokenType.NOT:
case TokenType.PLUS:
case TokenType.MULTIPLY:
case TokenType.DIVIDE:
case TokenType.MODULO:
{
if( _ops.Count == 0 || ComparePrecedence(token, (Yytoken)_ops.Peek()) > 0 ) // new token has higher precedence
{
_ops.Push(token);
}
else // new token has lower or same precedence
{
Reduce();
// process this token again
ProcessToken(token, lexer); // note: recursive call
}
break;
}
case TokenType.OP_IN:
case TokenType.FN_ISNULL:
case TokenType.FN_LEN:
case TokenType.FN_TRIM:
case TokenType.FN_LEFT:
case TokenType.FN_RIGHT:
case TokenType.FN_SUBSTR:
case TokenType.FN_UPPER:
case TokenType.FN_LOWER:
case TokenType.FN_EXISTS:
{
Yytoken nextToken = lexer.Lex();
if( nextToken.Type != TokenType.LPAREN )
{
throw new OPathException("Function '" + token.Text + "' must be followed by an opening parenthesis.");
}
_ops.Push(nextToken);
_ops.Push(token);
break;
}
case TokenType.LPAREN:
case TokenType.LBRACE:
{
_ops.Push(token);
break;
}
case TokenType.RPAREN:
{
if( _ops.Count == 0 ) throw new OPathException("Closing parenthesis encountered without matching opening parenthesis.");
if( ((Yytoken)_ops.Peek()).Type == TokenType.LPAREN )
{
_ops.Pop(); // "cancel" the operator pair
}
else
{
Reduce();
// process this token again
ProcessToken(token, lexer); // note: recursive call
}
break;
}
case TokenType.RBRACE:
{
if( _ops.Count == 0 ) throw new OPathException("Closing brace encountered without matching opening brace.");
if( ((Yytoken)_ops.Peek()).Type == TokenType.LBRACE )
{
Reduce(); // a final reduce to "cancel" the pair
}
else
{
Reduce();
// process this token again
ProcessToken(token, lexer); // note: recursive call
}
break;
}
default:
{
throw new NotSupportedException("Token type " + token.Type + " at position " + token.Position + " in expression is not supported.");
}
}
#if DEBUG_PARSER
DumpStacks("\nAfter Token: " + token.ToString());
#endif
}
