protected override object InternalVisit(SearchedCaseExpression node)
{
//TODO:node.Collation
Func <Environment, object> def = Visit <Func <Environment, object> >(node.ElseExpression);
//the key should be a predicate.
Dictionary <Func <Environment, object>, Func <Environment, object> > clauses = new Dictionary <Func <Environment, object>, Func <Environment, object> >();
foreach (var clause in node.WhenClauses)
{
clauses.Add(
Visit <Func <Environment, object> >(clause.WhenExpression),
Visit <Func <Environment, object> >(clause.ThenExpression)
);
}
return(new Func <Environment, object>((env) =>
{
foreach (var c in clauses)
{
if ((bool)c.Key(env))
{
return c.Value(env);
}
}
return def(env);
}));
}
public override void Visit(SearchedCaseExpression node) { this.action(node); }
protected override ScalarExpression ReplaceExpression(ScalarExpression expression, out string name)
{
name = null;
if (expression is CoalesceExpression coalesce)
{
var caseExpr = new SearchedCaseExpression();
foreach (var expr in coalesce.Expressions)
{
caseExpr.WhenClauses.Add(new SearchedWhenClause
{
WhenExpression = new BooleanIsNullExpression {
Expression = expr, IsNot = true
},
ThenExpression = expr
});
}
return(caseExpr);
}
if (expression is IIfCall iif)
{
var caseExpr = new SearchedCaseExpression
{
WhenClauses =
{
new SearchedWhenClause
{
WhenExpression = iif.Predicate,
ThenExpression = iif.ThenExpression
}
},
ElseExpression = iif.ElseExpression
};
return(caseExpr);
}
if (expression is LeftFunctionCall left)
{
var leftFunc = new FunctionCall
{
FunctionName = new Identifier {
Value = "LEFT"
}
};
foreach (var param in left.Parameters)
{
leftFunc.Parameters.Add(param);
}
return(leftFunc);
}
if (expression is NullIfExpression nullif)
{
var caseExpr = new SearchedCaseExpression
{
WhenClauses =
{
new SearchedWhenClause
{
WhenExpression = new BooleanComparisonExpression
{
ComparisonType = BooleanComparisonType.Equals,
FirstExpression = nullif.FirstExpression,
SecondExpression = nullif.SecondExpression
},
ThenExpression = new NullLiteral()
}
},
ElseExpression = nullif.FirstExpression
};
return(caseExpr);
}
if (expression is RightFunctionCall right)
{
var rightFunc = new FunctionCall
{
FunctionName = new Identifier {
Value = "RIGHT"
}
};
foreach (var param in right.Parameters)
{
rightFunc.Parameters.Add(param);
}
return(rightFunc);
}
if (expression is UnaryExpression unary && unary.Expression is IntegerLiteral integer && unary.UnaryExpressionType != UnaryExpressionType.BitwiseNot)
{
if (unary.UnaryExpressionType == UnaryExpressionType.Negative)
{
var value = Int32.Parse(integer.Value, CultureInfo.InvariantCulture);
integer.Value = (-value).ToString();
return(integer);
}
}
return(expression);
}
public override void ExplicitVisit(SearchedCaseExpression fragment)
{
_fragments.Add(fragment);
}
protected override object InternalVisit(SearchedCaseExpression node)
{
//TODO: node.Cursor
return(new SQLExpressionInterpreter(Database).Visit <object>(node));
}
protected override ScalarExpression ReplaceExpression(ScalarExpression expression, out string name)
{
name = null;
if (expression is CoalesceExpression coalesce)
{
var caseExpr = new SearchedCaseExpression();
foreach (var expr in coalesce.Expressions)
{
caseExpr.WhenClauses.Add(new SearchedWhenClause
{
WhenExpression = new BooleanIsNullExpression {
Expression = expr, IsNot = true
},
ThenExpression = expr
});
}
return(caseExpr);
}
if (expression is IIfCall iif)
{
var caseExpr = new SearchedCaseExpression
{
WhenClauses =
{
new SearchedWhenClause
{
WhenExpression = iif.Predicate,
ThenExpression = iif.ThenExpression
}
},
ElseExpression = iif.ElseExpression
};
return(caseExpr);
}
if (expression is LeftFunctionCall left)
{
var leftFunc = new FunctionCall
{
FunctionName = new Identifier {
Value = "LEFT"
}
};
foreach (var param in left.Parameters)
{
leftFunc.Parameters.Add(param);
}
return(leftFunc);
}
if (expression is NullIfExpression nullif)
{
var caseExpr = new SearchedCaseExpression
{
WhenClauses =
{
new SearchedWhenClause
{
WhenExpression = new BooleanComparisonExpression
{
ComparisonType = BooleanComparisonType.Equals,
FirstExpression = nullif.FirstExpression,
SecondExpression = nullif.SecondExpression
},
ThenExpression = new NullLiteral()
}
},
ElseExpression = nullif.FirstExpression
};
return(caseExpr);
}
if (expression is RightFunctionCall right)
{
var rightFunc = new FunctionCall
{
FunctionName = new Identifier {
Value = "RIGHT"
}
};
foreach (var param in right.Parameters)
{
rightFunc.Parameters.Add(param);
}
return(rightFunc);
}
return(expression);
}
private List <TableParsingResult> ExtractTableNamesFromSearchedCaseExpression(SearchedCaseExpression searchedCaseExpression)
{
List <TableParsingResult> result = new List <TableParsingResult>();
foreach (SearchedWhenClause whenClause in searchedCaseExpression.WhenClauses)
{
if (whenClause.ThenExpression is BinaryExpression binaryExpression)
{
var items1 = ExtractTablesFromBinaryExpression(binaryExpression);
result.AddIfNotExists(items1);
}
else
{
Debug.WriteLine($"SearchedWhenClause {whenClause.GetType().FullName} not analyzed");
}
}
return(result);
}
public gsScalarExpressionParserSearchedCase(ScalarExpression expression, string columnAlias)
: base(expression, columnAlias)
{
_ScalarExpression = expression as SearchedCaseExpression;
}
