diesel/macros/
static_cond.rs

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1#![cfg_attr(rustfmt, rustfmt_skip)] // https://github.com/rust-lang-nursery/rustfmt/issues/2754
2
3// Vendored from the static-cond crate as macro re-exports are not available in stable Rust.
4// https://github.com/durka/static-cond/blob/36aa2dd/src/lib.rs
5//
6// Code is dual licensed under MIT/Apache-2.0
7// Copyright (c) 2016 Alex Burka
8#[macro_export]
9#[doc(hidden)]
10macro_rules! static_cond {
11    // private rule to define and call the local macro
12    (@go $lhs:tt $rhs:tt $arm1:tt $arm2:tt) => {
13        // note that the inner macro has no captures (it can't, because there's no way to escape `$`)
14        macro_rules! __static_cond {
15            ($lhs $lhs) => $arm1;
16            ($lhs $rhs) => $arm2
17        }
18
19        __static_cond!($lhs $rhs);
20    };
21
22    // no else condition provided: fall through with empty else
23    (if $lhs:tt == $rhs:tt $then:tt) => {
24        $crate::static_cond!(if $lhs == $rhs $then else { });
25    };
26    (if $lhs:tt != $rhs:tt $then:tt) => {
27        $crate::static_cond!(if $lhs != $rhs $then else { });
28    };
29
30    // we evaluate a conditional by generating a new macro (in an inner scope, so name shadowing is
31    // not a big concern) and calling it
32    (if $lhs:tt == $rhs:tt $then:tt else $els:tt) => {
33        $crate::static_cond!(@go $lhs $rhs $then $els);
34    };
35    (if $lhs:tt != $rhs:tt $then:tt else $els:tt) => {
36        $crate::static_cond!(@go $lhs $rhs $els $then);
37    };
38}
diesel/macros/static_cond.rs

diesel/macros/
static_cond.rs
