caret/
lib.rs

1#![cfg_attr(docsrs, feature(doc_auto_cfg, doc_cfg))]
2#![doc = include_str!("../README.md")]
3// @@ begin lint list maintained by maint/add_warning @@
4#![allow(renamed_and_removed_lints)] // @@REMOVE_WHEN(ci_arti_stable)
5#![allow(unknown_lints)] // @@REMOVE_WHEN(ci_arti_nightly)
6#![warn(missing_docs)]
7#![warn(noop_method_call)]
8#![warn(unreachable_pub)]
9#![warn(clippy::all)]
10#![deny(clippy::await_holding_lock)]
11#![deny(clippy::cargo_common_metadata)]
12#![deny(clippy::cast_lossless)]
13#![deny(clippy::checked_conversions)]
14#![warn(clippy::cognitive_complexity)]
15#![deny(clippy::debug_assert_with_mut_call)]
16#![deny(clippy::exhaustive_enums)]
17#![deny(clippy::exhaustive_structs)]
18#![deny(clippy::expl_impl_clone_on_copy)]
19#![deny(clippy::fallible_impl_from)]
20#![deny(clippy::implicit_clone)]
21#![deny(clippy::large_stack_arrays)]
22#![warn(clippy::manual_ok_or)]
23#![deny(clippy::missing_docs_in_private_items)]
24#![warn(clippy::needless_borrow)]
25#![warn(clippy::needless_pass_by_value)]
26#![warn(clippy::option_option)]
27#![deny(clippy::print_stderr)]
28#![deny(clippy::print_stdout)]
29#![warn(clippy::rc_buffer)]
30#![deny(clippy::ref_option_ref)]
31#![warn(clippy::semicolon_if_nothing_returned)]
32#![warn(clippy::trait_duplication_in_bounds)]
33#![deny(clippy::unchecked_duration_subtraction)]
34#![deny(clippy::unnecessary_wraps)]
35#![warn(clippy::unseparated_literal_suffix)]
36#![deny(clippy::unwrap_used)]
37#![deny(clippy::mod_module_files)]
38#![allow(clippy::let_unit_value)] // This can reasonably be done for explicitness
39#![allow(clippy::uninlined_format_args)]
40#![allow(clippy::significant_drop_in_scrutinee)] // arti/-/merge_requests/588/#note_2812945
41#![allow(clippy::result_large_err)] // temporary workaround for arti#587
42#![allow(clippy::needless_raw_string_hashes)] // complained-about code is fine, often best
43#![allow(clippy::needless_lifetimes)] // See arti#1765
44#![allow(mismatched_lifetime_syntaxes)] // temporary workaround for arti#2060
45//! <!-- @@ end lint list maintained by maint/add_warning @@ -->
46
47/// Declare an integer type with some named elements.
48///
49/// This macro declares a struct that wraps an integer
50/// type, and allows any integer type as a value.  Some values of this type
51/// have names, and others do not, but they are all allowed.
52///
53/// This macro is suitable for protocol implementations that accept
54/// any integer on the wire, and have definitions for some of those
55/// integers.  For example, Tor cell commands are 8-bit integers, but
56/// not every u8 is a currently recognized Tor command.
57///
58/// # Examples
59/// ```
60/// use caret::caret_int;
61/// caret_int! {
62///     pub struct FruitID(u8) {
63///         AVOCADO = 7,
64///         PERSIMMON = 8,
65///         LONGAN = 99
66///     }
67/// }
68///
69/// // Known fruits work the way we would expect...
70/// let a_num: u8 = FruitID::AVOCADO.into();
71/// assert_eq!(a_num, 7);
72/// let a_fruit: FruitID = 8.into();
73/// assert_eq!(a_fruit, FruitID::PERSIMMON);
74/// assert_eq!(format!("I'd like a {}", FruitID::PERSIMMON),
75///            "I'd like a PERSIMMON");
76///
77/// // And we can construct unknown fruits, if we encounter any.
78/// let weird_fruit: FruitID = 202.into();
79/// assert_eq!(format!("I'd like a {}", weird_fruit),
80///            "I'd like a 202");
81/// ```
82#[macro_export]
83macro_rules! caret_int {
84    {
85       $(#[$meta:meta])*
86       $v:vis struct $name:ident ( $numtype:ty ) {
87           $(
88               $(#[$item_meta:meta])*
89               $id:ident = $num:literal
90           ),*
91           $(,)?
92      }
93    } => {
94        #[derive(PartialEq,Eq,Copy,Clone)]
95        $(#[$meta])*
96        $v struct $name($numtype);
97
98        impl From<$name> for $numtype {
99            fn from(val: $name) -> $numtype { val.0 }
100        }
101        impl From<$numtype> for $name {
102            fn from(num: $numtype) -> $name { $name(num) }
103        }
104        impl $name {
105            $(
106                $( #[$item_meta] )*
107                pub const $id: $name = $name($num) ; )*
108            fn to_str(self) -> Option<&'static str> {
109                match self {
110                    $( $name::$id => Some(stringify!($id)), )*
111                    _ => None,
112                }
113            }
114            /// Return true if this value is one that we recognize.
115            $v fn is_recognized(self) -> bool {
116                match self {
117                    $( $name::$id  => true, )*
118                    _ => false
119                }
120            }
121            /// Try to convert this value from one of the recognized names.
122            $v fn from_name(name: &str) -> Option<Self> {
123                match name {
124                    $( stringify!($id) => Some($name::$id), )*
125                    _ => None
126                }
127            }
128            /// Return the underlying integer that this value represents.
129            fn get(self) -> $numtype {
130                self.into()
131            }
132        }
133        impl std::fmt::Display for $name {
134            fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
135                match self.to_str() {
136                    Some(s) => write!(f, "{}", s),
137                    None => write!(f, "{}", self.0),
138                }
139            }
140        }
141        // `#[educe(Debug)]` could do this for us, but let's not deepen this macrology
142        impl std::fmt::Debug for $name {
143            fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
144                write!(f, "{}({})", stringify!($name), self)
145            }
146        }
147    };
148
149}