public Expression ConvertFluentToQuery(Expression node)
{
node = node.Clone();
var artificialParent = new ExpressionStatement();
artificialParent.Expression = node;
DecompileQueries(node);
// After all queries were decompiled, detect degenerate queries (queries not property terminated with 'select' or 'group')
// and fix them, either by adding a degenerate select, or by combining them with another query.
foreach (QueryExpression query in artificialParent.Descendants.OfType <QueryExpression>())
{
QueryFromClause fromClause = (QueryFromClause)query.Clauses.First();
if (IsDegenerateQuery(query))
{
string identifierName = fromClause.Identifier;
// introduce select for degenerate query
query.Clauses.Add(new QuerySelectClause {
Expression = new IdentifierExpression(identifierName)
});
}
if (fromClause.Type.IsNull)
{
// See if the data source of this query is a degenerate query,
// and combine the queries if possible.
QueryExpression innerQuery = fromClause.Expression as QueryExpression;
while (IsDegenerateQuery(innerQuery))
{
QueryFromClause innerFromClause = (QueryFromClause)innerQuery.Clauses.First();
if (fromClause.Identifier != innerFromClause.Identifier && !innerFromClause.Identifier.StartsWith("<>"))
{
break;
}
// Replace the fromClause with all clauses from the inner query
fromClause.Remove();
foreach (var identifierChild in innerQuery.Descendants.OfType <Identifier>().Where(identifier => identifier.Name == innerFromClause.Identifier))
{
//When the identifier is "<>X", then replace it with the outer one
identifierChild.ReplaceWith(fromClause.IdentifierToken.Clone());
}
QueryClause insertionPos = null;
foreach (var clause in innerQuery.Clauses)
{
query.Clauses.InsertAfter(insertionPos, insertionPos = clause.Detach());
}
fromClause = innerFromClause;
innerQuery = fromClause.Expression as QueryExpression;
}
}
}
return(artificialParent.Expression.Clone());
}
bool TryRemoveTransparentIdentifier(QueryExpression query, QueryFromClause fromClause, QueryExpression innerQuery, string continuationIdentifier, out string transparentIdentifier)
{
transparentIdentifier = fromClause.Identifier;
Match match = selectTransparentIdentifierPattern.Match(innerQuery.Clauses.Last());
if (!match.Success)
{
return(false);
}
QuerySelectClause selectClause = (QuerySelectClause)innerQuery.Clauses.Last();
Expression nae1 = match.Get <Expression>("nae1").SingleOrDefault();
string nae1Name = ExtractExpressionName(ref nae1);
if (nae1Name == null)
{
return(false);
}
Expression nae2 = match.Get <Expression>("nae2").SingleOrDefault();
string nae2Name = ExtractExpressionName(ref nae2);
if (nae1Name == null)
{
return(false);
}
bool introduceLetClause = true;
var nae1Identifier = nae1 as IdentifierExpression;
var nae2Identifier = nae2 as IdentifierExpression;
if (nae1Identifier != null && nae2Identifier != null && nae1Identifier.Identifier == nae1Name && nae2Identifier.Identifier == nae2Name)
{
introduceLetClause = false;
}
if (nae1Name != continuationIdentifier)
{
if (nae2Name == continuationIdentifier)
{
//Members are in reversed order
string tempName = nae1Name;
Expression tempNae = nae1;
nae1Name = nae2Name;
nae1 = nae2;
nae2Name = tempName;
nae2 = tempNae;
}
else
{
return(false);
}
}
if (introduceLetClause && innerQuery.Clauses.OfType <QueryFromClause>().Any(from => from.Identifier == nae2Name))
{
return(false);
}
if (introduceLetClause && innerQuery.Clauses.OfType <QueryJoinClause>().Any(join => join.JoinIdentifier == nae2Name))
{
return(false);
}
// from * in (from x in ... select new { x = x, y = expr }) ...
// =>
// from x in ... let y = expr ...
fromClause.Remove();
selectClause.Remove();
// Move clauses from innerQuery to query
QueryClause insertionPos = null;
foreach (var clause in innerQuery.Clauses)
{
query.Clauses.InsertAfter(insertionPos, insertionPos = clause.Detach());
}
if (introduceLetClause)
{
query.Clauses.InsertAfter(insertionPos, new QueryLetClause {
Identifier = nae2Name, Expression = nae2.Detach()
});
}
return(true);
}