diesel/expression/ops/
numeric.rs

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1use crate::backend::Backend;
2use crate::expression::{Expression, TypedExpressionType, ValidGrouping};
3use crate::query_builder::*;
4use crate::result::QueryResult;
5use crate::sql_types;
6
7macro_rules! numeric_operation {
8    ($name:ident, $op:expr) => {
9        #[doc(hidden)]
10        #[derive(Debug, Copy, Clone, QueryId, ValidGrouping)]
11        pub struct $name<Lhs, Rhs> {
12            lhs: Lhs,
13            rhs: Rhs,
14        }
15
16        impl<Lhs, Rhs> $name<Lhs, Rhs> {
17            // This function is used by `operator_allowed!`
18            // which is internally used by `table!`
19            // for "numeric" columns
20            #[doc(hidden)]
21            pub fn new(left: Lhs, right: Rhs) -> Self {
22                $name {
23                    lhs: left,
24                    rhs: right,
25                }
26            }
27        }
28
29        impl<Lhs, Rhs> Expression for $name<Lhs, Rhs>
30        where
31            Lhs: Expression,
32            Lhs::SqlType: sql_types::ops::$name,
33            Rhs: Expression,
34            <Lhs::SqlType as sql_types::ops::$name>::Output: TypedExpressionType,
35        {
36            type SqlType = <Lhs::SqlType as sql_types::ops::$name>::Output;
37        }
38
39        impl<Lhs, Rhs, DB> QueryFragment<DB> for $name<Lhs, Rhs>
40        where
41            DB: Backend,
42            Lhs: QueryFragment<DB>,
43            Rhs: QueryFragment<DB>,
44        {
45            fn walk_ast<'b>(&'b self, mut out: AstPass<'_, 'b, DB>) -> QueryResult<()>
46            {
47                out.push_sql("(");
48                self.lhs.walk_ast(out.reborrow())?;
49                out.push_sql($op);
50                self.rhs.walk_ast(out.reborrow())?;
51                out.push_sql(")");
52                Ok(())
53            }
54        }
55
56        impl_selectable_expression!($name<Lhs, Rhs>);
57        generic_numeric_expr!($name, A, B);
58    };
59}
60
61numeric_operation!(Add, " + ");
62numeric_operation!(Sub, " - ");
63numeric_operation!(Mul, " * ");
64numeric_operation!(Div, " / ");
diesel/expression/ops/numeric.rs

diesel/expression/ops/
numeric.rs
