ip_macro/
lib.rs

1#![feature(proc_macro)]
2
3/// Macros for writing literal IP addresses.
4///
5/// This crate provides three macros:
6///
7/// * `ip!()`
8/// * `ipv4!()`
9/// * `ipv6!()`
10///
11/// All of these take a single argument: a string literal representing an IP
12/// address. `ipv4!()` and `ipv6!()` return an `Ipv4Addr` and `Ipv6Addr`,
13/// respectively. `ip!()` parses a generic `IpAddr`, which can be either an IPv4
14/// or an IPv6 address.
15///
16/// # Example
17///
18/// ```rust
19/// #![feature(proc_macro)]  // <- Don't forget this!
20///
21/// extern crate ip_macro;
22/// use ip_macro::ip;
23///
24/// fn main() {
25///     println!("There's no place like {}", ip!("127.0.0.1"));
26/// }
27/// ```
28
29extern crate proc_macro;
30#[macro_use]
31extern crate quote;
32extern crate syn;
33
34use proc_macro::TokenStream;
35use quote::Tokens;
36use std::fmt::Debug;
37use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};
38use std::str::FromStr;
39
40#[proc_macro]
41pub fn ip(input: TokenStream) -> TokenStream {
42    parse_ts(match parse_string_literal(input, "IP address") {
43        IpAddr::V4(addr) => {
44            let q = quote_ipv4(addr);
45            quote!(::std::net::IpAddr::V4(#q))
46        }
47        IpAddr::V6(addr) => {
48            let q = quote_ipv6(addr);
49            quote!(::std::net::IpAddr::V6(#q))
50        }
51    })
52}
53
54#[proc_macro]
55pub fn ipv4(input: TokenStream) -> TokenStream {
56    parse_ts(quote_ipv4(parse_string_literal(input, "IPv4 address")))
57}
58
59#[proc_macro]
60pub fn ipv6(input: TokenStream) -> TokenStream {
61    parse_ts(quote_ipv6(parse_string_literal(input, "IPv6 address")))
62}
63
64fn parse_string_literal<T>(input: TokenStream, expected: &'static str) -> T
65    where T: FromStr,
66          T::Err: Debug
67{
68    match syn::parse::string(&input.to_string()).expect("string literal").value.parse() {
69        Ok(r) => r,
70        Err(_) => panic!("invalid {}", expected),
71    }
72}
73
74fn quote_ipv4(addr: Ipv4Addr) -> Tokens {
75    let octets = addr.octets();
76    quote!(::std::net::Ipv4Addr::new(#(#octets),*))
77}
78
79fn quote_ipv6(addr: Ipv6Addr) -> Tokens {
80    let segments = addr.segments();
81    quote!(::std::net::Ipv6Addr::new(#(#segments),*))
82}
83
84fn parse_ts(tokens: Tokens) -> TokenStream {
85    tokens.as_str().parse().unwrap()
86}
ip_macro/lib.rs

ip_macro/
lib.rs
