public static Expression ReplaceTransparentIdentifiers(Expression expression)
{
Expression expressionBeforeRemove;
Expression expressionAfterRemove = expression;
// Run again and again until no replacements have been made.
do
{
expressionBeforeRemove = expressionAfterRemove;
expressionAfterRemove = new TransparentIdentifierRemovingExpressionVisitor().Visit(expressionAfterRemove);
} while (expressionAfterRemove != expressionBeforeRemove);
return(expressionAfterRemove);
}
public static Expression FlattenGroupingKey(Expression expression)
{
var visitor = new GroupingKeyFlattener();
expression = visitor.Visit(expression);
if (visitor._flattened)
{
expression = TransparentIdentifierRemovingExpressionVisitor.ReplaceTransparentIdentifiers(expression);
// When the grouping key is an array we have to unwrap it (e.g. group.Key[0] == variable)
if (expression.NodeType == ExpressionType.ArrayIndex &&
expression is BinaryExpression binaryExpression &&
binaryExpression.Left is NewArrayExpression newArray &&
binaryExpression.Right is ConstantExpression indexExpression &&
indexExpression.Value is int index)
{
return newArray.Expressions[index];
}
}
return expression;
}
public Expression Swap(Expression expression)
{
return(TransparentIdentifierRemovingExpressionVisitor.ReplaceTransparentIdentifiers(Visit(expression)));
}