Object - part of the language, or part of Phobos?

[Steve Teale]

Jacob,

So lets say I've got a result set from a database. I was thinking it would be tidy
and convenient if you could dress the result set up as a random access range, and
just pop the current row into a user defined struct without having to copy each
field, and was wondering if D had sufficient introspection to let me do this in a
way that was reasonably robust. If the compiler could tell me the names of the
struct fields and the offsets, then I could get the column names and types from
the database, and bingo! But it cant.

Nonetheless, I was experimenting, and then I noticed that the class TypeInfo
OffsetTypeInfo[] offTi() method does not return anything useful.

That might be understandable if TypeInfo applied only to classes. Derived classes
could make this method do something useful. But it doesn't - you can get an
instance for __all types__ via typeid. So the implementation in the runtime should
provide some sensible information for structs. Hence this thread.

I can get the field types and offsets using templates defined in std.traits and
std.typecons, but there's no way to get the names of the fields.

However, I may still do it. The situation I'm considering is one where the
programmer is in charge and can make the call as to whether the convenience is
worth the risk. I can only protect her against type mismatches.

Steve