diesel/macros/
ops.rs

1#[macro_export]
2/// Implements the Rust operator for a given type. If you create a new SQL
3/// function, which returns a type that you'd like to use an operator on, you
4/// should invoke this macro. Unfortunately, Rust disallows us from
5/// automatically implementing `Add` and other traits from `std::ops`, under its
6/// orphan rules.
7macro_rules! operator_allowed {
8    ($tpe:ty, $op:ident, $fn_name:ident) => {
9        impl<Rhs> ::std::ops::$op<Rhs> for $tpe
10        where
11            Rhs: $crate::expression::AsExpression<
12                <<$tpe as $crate::Expression>::SqlType as $crate::sql_types::ops::$op>::Rhs,
13            >,
14        {
15            type Output = $crate::expression::ops::$op<Self, Rhs::Expression>;
16
17            fn $fn_name(self, rhs: Rhs) -> Self::Output {
18                $crate::expression::ops::$op::new(self, rhs.as_expression())
19            }
20        }
21    };
22}
23
24#[macro_export]
25/// Indicates that an expression allows all numeric operators. If you create new
26/// SQL functions that return a numeric type, you should invoke this macro that
27/// type. Unfortunately, Rust disallows us from automatically implementing `Add`
28/// for types which implement `Expression`, under its orphan rules.
29macro_rules! numeric_expr {
30    ($tpe:ty) => {
31        operator_allowed!($tpe, Add, add);
32        operator_allowed!($tpe, Sub, sub);
33        operator_allowed!($tpe, Div, div);
34        operator_allowed!($tpe, Mul, mul);
35    };
36}
37
38#[macro_export]
39#[doc(hidden)]
40macro_rules! __diesel_generate_ops_impls_if_numeric {
41    ($column_name:ident, Nullable<$($inner:tt)::*>) => { __diesel_generate_ops_impls_if_numeric!($column_name, $($inner)::*); };
42
43    ($column_name:ident, SmallInt) => { numeric_expr!($column_name); };
44    ($column_name:ident, Int2) => { numeric_expr!($column_name); };
45    ($column_name:ident, Smallint) => { numeric_expr!($column_name); };
46    ($column_name:ident, SmallSerial) => { numeric_expr!($column_name); };
47
48    ($column_name:ident, Integer) => { numeric_expr!($column_name); };
49    ($column_name:ident, Int4) => { numeric_expr!($column_name); };
50    ($column_name:ident, Serial) => { numeric_expr!($column_name); };
51
52    ($column_name:ident, BigInt) => { numeric_expr!($column_name); };
53    ($column_name:ident, Int8) => { numeric_expr!($column_name); };
54    ($column_name:ident, Bigint) => { numeric_expr!($column_name); };
55    ($column_name:ident, BigSerial) => { numeric_expr!($column_name); };
56
57    ($column_name:ident, Float) => { numeric_expr!($column_name); };
58    ($column_name:ident, Float4) => { numeric_expr!($column_name); };
59
60    ($column_name:ident, Double) => { numeric_expr!($column_name); };
61    ($column_name:ident, Float8) => { numeric_expr!($column_name); };
62
63    ($column_name:ident, Numeric) => { numeric_expr!($column_name); };
64
65    ($column_name:ident, $non_numeric_type:ty) => {};
66}
67
68#[macro_export]
69#[doc(hidden)]
70macro_rules! date_time_expr {
71    ($tpe:ty) => {
72        operator_allowed!($tpe, Add, add);
73        operator_allowed!($tpe, Sub, sub);
74    };
75}
76
77#[macro_export]
78#[doc(hidden)]
79macro_rules! __diesel_generate_ops_impls_if_date_time {
80    ($column_name:ident, Nullable<$($inner:tt)::*>) => { __diesel_generate_ops_impls_if_date_time!($column_name, $($inner)::*); };
81    ($column_name:ident, Time) => { date_time_expr!($column_name); };
82    ($column_name:ident, Date) => { date_time_expr!($column_name); };
83    ($column_name:ident, Timestamp) => { date_time_expr!($column_name); };
84    ($column_name:ident, Timestamptz) => { date_time_expr!($column_name); };
85    ($column_name:ident, $non_date_time_type:ty) => {};
86}
diesel/macros/ops.rs

diesel/macros/
ops.rs
