public ToStringExpressionVisitor(ParameterExpression param, CachedEntityExpression root)
{
this.root = root;
this.replacements = new Dictionary <ParameterExpression, Expression> {
{ param, root }
};
}
public static Expression <Func <PrimaryKey, string> > GetToString <T>(CachedTableConstructor constructor, Expression <Func <T, string> > lambda)
{
Table table = (Table)constructor.table;
var param = lambda.Parameters.SingleEx();
if (param.Type != table.Type)
{
throw new InvalidOperationException("incorrect lambda paramer type");
}
var pk = Expression.Parameter(typeof(PrimaryKey), "pk");
var root = new CachedEntityExpression(pk, typeof(T), constructor, null, null);
var visitor = new ToStringExpressionVisitor(param, root);
var result = visitor.Visit(lambda.Body);
return(Expression.Lambda <Func <PrimaryKey, string> >(result, pk));
}
private Expression BindMember(CachedEntityExpression n, Field field, Expression?prevPrimaryKey)
{
Expression body = GetField(field, n.Constructor, prevPrimaryKey);
ConstantExpression tab = Expression.Constant(n.Constructor.cachedTable, typeof(CachedTable <>).MakeGenericType(((Table)n.Constructor.table).Type));
Expression origin = Expression.Convert(Expression.Property(Expression.Call(tab, "GetRows", null), "Item", n.PrimaryKey.UnNullify()), n.Constructor.tupleType);
var result = ExpressionReplacer.Replace(body, new Dictionary <ParameterExpression, Expression> {
{ n.Constructor.origin, origin }
});
if (!n.PrimaryKey.Type.IsNullable())
{
return(result);
}
return(Expression.Condition(
Expression.Equal(n.PrimaryKey, Expression.Constant(null, n.PrimaryKey.Type)),
Expression.Constant(null, result.Type.Nullify()),
result.Nullify()));
}
