qraft_core/select/
group.rs

1//! Grouping helpers for `group by`.
2
3use crate::{
4    count_idents,
5    expression::Expression,
6    impl_for_all_tuples,
7    lower::{Instructions, LowerCtx},
8};
9
10/// Lowers one or more grouping expressions.
11pub trait LowerGroupBy {
12    /// Appends the grouping node or nodes to the lowering context.
13    fn lower_group_by(self, ctx: &mut LowerCtx);
14}
15
16impl<E> LowerGroupBy for E
17where
18    E: Expression,
19{
20    fn lower_group_by(self, ctx: &mut LowerCtx) {
21        self.lower(ctx);
22    }
23}
24
25macro_rules! impl_groupby_macro {
26    ($($T:ident),+) => {
27        impl<$($T,)+> LowerGroupBy for ($($T,)+)
28        where
29            $($T: LowerGroupBy,)+
30        {
31            fn lower_group_by(self, ctx: &mut LowerCtx) {
32                #[allow(non_snake_case)]
33                let ($($T,)+) = self;
34                $(
35                    $T.lower_group_by(ctx);
36                )+
37                let count = count_idents!($($T,)+);
38                ctx.instrs.push_seperated(count);
39            }
40        }
41    };
42}
43
44impl_for_all_tuples!(impl_groupby_macro);
qraft_core/select/group.rs

qraft_core/select/
group.rs
