diesel/query_builder/
clause_macro.rs

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1macro_rules! simple_clause {
2    (
3        $(#[$no_clause_meta: meta])*
4        $no_clause:ident,
5        $(#[$clause_meta: meta])*
6        $clause:ident,
7        $sql:expr
8    ) => {
9        simple_clause!(
10            $(#[$no_clause_meta])*
11            $no_clause,
12            $(#[$clause_meta])*
13            $clause,
14            $sql,
15            backend_bounds =
16        );
17    };
18
19    (
20        $(#[$no_clause_meta: meta])*
21        $no_clause:ident,
22        $(#[$clause_meta: meta])*
23        $clause:ident,
24        $sql:expr,
25        backend_bounds = $($backend_bounds:ident),*
26    ) => {
27        use crate::backend::{Backend, DieselReserveSpecialization};
28        use crate::result::QueryResult;
29        use crate::query_builder::QueryId;
30        use super::{QueryFragment, AstPass};
31
32        $(#[$no_clause_meta])*
33        #[derive(Debug, Clone, Copy, QueryId)]
34        pub struct $no_clause;
35
36        impl<DB> QueryFragment<DB> for $no_clause where
37            DB: Backend + DieselReserveSpecialization,
38        {
39            fn walk_ast<'b>(&'b self, _: AstPass<'_, 'b, DB>) -> QueryResult<()>
40            {
41                Ok(())
42            }
43        }
44
45        $(#[$clause_meta])*
46        #[derive(Debug, Clone, Copy, QueryId)]
47        pub struct $clause<Expr>(pub Expr);
48
49        impl<Expr, DB> QueryFragment<DB> for $clause<Expr> where
50            DB: Backend + DieselReserveSpecialization $(+ $backend_bounds)*,
51            Expr: QueryFragment<DB>,
52        {
53            fn walk_ast<'b>(&'b self, mut out: AstPass<'_, 'b, DB>) -> QueryResult<()>
54            {
55                out.push_sql($sql);
56                self.0.walk_ast(out.reborrow())?;
57                Ok(())
58            }
59        }
60    }
61}
diesel/query_builder/clause_macro.rs

diesel/query_builder/
clause_macro.rs
