Got unknown return type

[MaxKingPor]

  --> src/lib.rs:21:1
   |
21 | #[pg_extern]
   | ^^^^^^^^^^^^
   |
   = help: message: called `Result::unwrap()` on an `Err` value: Error("Got unknown return type: ImplTrait(TypeImplTrait { impl_token: Impl, bounds: [Trait(TraitBound { paren_token: None, modifier: None, lifetimes: None, path: Path { leading_colon: None, segments: [PathSegment { ident: Ident { ident: \"Iterator\", span: #0 bytes(309..317) }, arguments: AngleBracketed(AngleBracketedGenericArguments { colon2_token: None, lt_token: Lt, args: [Binding(Binding { ident: Ident { ident: \"Item\", span: #0 bytes(318..322) }, eq_token: Eq, ty: Tuple(TypeTuple { paren_token: Paren, elems: [Macro(TypeMacro { mac: Macro { path: Path { leading_colon: None, segments: [PathSegment { ident: Ident { ident: \"name\", span: #0 bytes(326..330) }, arguments: None }] }, bang_token: Bang, delimiter: Paren(Paren), tokens: TokenStream [Ident { ident: \"a\", span: #0 bytes(332..333) }, Punct { ch: ',', spacing: Alone, span: #0 bytes(333..334) }, Ident { ident: \"i32\", span: #0 bytes(335..338) }] } }), Comma, Macro(TypeMacro { mac: Macro { path: Path { leading_colon: None, segments: [PathSegment { ident: Ident { ident: \"name\", span: #0 bytes(341..345) }, arguments: None }] }, bang_token: Bang, delimiter: Paren(Paren), tokens: TokenStream [Ident { ident: \"b\", span: #0 bytes(347..348) }, Punct { ch: ',', spacing: Alone, span: #0 bytes(348..349) }, Ident { ident: \"i32\", span: #0 bytes(350..353) }] } })] }) })], gt_token: Gt }) }] } })] })")

[workingjubilee]

You probably need to be using TableIterator<'a, T>.

[workingjubilee]

@MaxKingPor Does that answer your question?

#[pg_extern]
fn floop<'a>() -> TableIterator<'a, (name!(a, i32), name!(b, i32))> {
    TableIterator::new(None.into_iter())
}

容易理解吗？

[MaxKingPor]

@MaxKingPor Does that answer your question?

#[pg_extern]
fn floop<'a>() -> TableIterator<'a, (name!(a, i32), name!(b, i32))> {
    TableIterator::new(None.into_iter())
}

容易理解吗？

Thank you. But Your document has not been modified

[workingjubilee]

Ah, will fix that.

[kavirajk]

Also got similar error for following example.

#[pg_extern]
fn generate_series(start: i64, end: i64, step: default!(i64, 1)) -> impl std::iter::Iterator {
    (start..end).into_iter().step_by(step as usize).into_iter()
}

error: Got unknown return type: ImplTrait(TypeImplTrait { impl_token: Impl, bounds: [Trait(TraitBound { paren_token: None, modifier: None, lifetimes: None, path: Path { leading_colon: None, segments: [PathSegment { ident: Ident { ident: "std", span: #0 bytes(565..568) }, arguments: None }, Colon2, PathSegment { ident: Ident { ident: "iter", span: #0 bytes(570..574) }, arguments: None }, Colon2, PathSegment { ident: Ident { ident: "Iterator", span: #0 bytes(576..584) }, arguments: None }] } })] })
  --> src/lib.rs:25:1
   |
25 | #[pg_extern]
   | ^^^^^^^^^^^^
   |
   = note: this error originates in the attribute macro `pg_extern` (in Nightly builds, run with -Z macro-backtrace for more info)

Followed example from this video.
https://www.youtube.com/watch?v=RORkgaURcS0&t=555s&ab_channel=PostgresConference

So my understanding is pgx doesn't allow normal impl std::iterator::Iterator as return value any more? Instead I have to use one of the SetOfIterator or TableIterator only? But those two doesn't look like correct iterators for my use case here.

@workingjubilee

[workingjubilee]

wow didn't see this.

Yes, that's correct.

[workingjubilee]

As far as Postgres is concerned, fn generate_series<'a, T>(start: T, end: T, step: i64) -> SetOfIterator<'a, T>.