reminder-bot/regex_command_attr/src/lib.rs

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#![deny(rust_2018_idioms)]
// FIXME: Remove this in a foreseeable future.
// Currently exists for backwards compatibility to previous Rust versions.
#![recursion_limit = "128"]
#[allow(unused_extern_crates)]
extern crate proc_macro;
use proc_macro::TokenStream;
use quote::quote;
use syn::{
parse::Error,
parse_macro_input, parse_quote,
spanned::Spanned,
Lit,
};
pub(crate) mod attributes;
pub(crate) mod consts;
pub(crate) mod structures;
#[macro_use]
pub(crate) mod util;
use attributes::*;
use consts::*;
use structures::*;
use util::*;
macro_rules! match_options {
($v:expr, $values:ident, $options:ident, $span:expr => [$($name:ident);*]) => {
match $v {
$(
stringify!($name) => $options.$name = propagate_err!($crate::attributes::parse($values)),
)*
_ => {
return Error::new($span, format_args!("invalid attribute: {:?}", $v))
.to_compile_error()
.into();
},
}
};
}
#[proc_macro_attribute]
pub fn command(attr: TokenStream, input: TokenStream) -> TokenStream {
let mut fun = parse_macro_input!(input as CommandFun);
let lit_name = if !attr.is_empty() {
parse_macro_input!(attr as Lit).to_str()
} else {
fun.name.to_string()
};
let mut options = Options::new();
for attribute in &fun.attributes {
let span = attribute.span();
let values = propagate_err!(parse_values(attribute));
let name = values.name.to_string();
let name = &name[..];
match_options!(name, values, options, span => [
permission_level;
supports_dm;
can_blacklist
]);
}
let Options {
permission_level,
supports_dm,
can_blacklist,
} = options;
propagate_err!(create_declaration_validations(&mut fun, DeclarFor::Command));
let res = parse_quote!(serenity::framework::standard::CommandResult);
create_return_type_validation(&mut fun, res);
let visibility = fun.visibility;
let name = fun.name.clone();
let body = fun.body;
let ret = fun.ret;
let n = name.with_suffix(COMMAND);
let cooked = fun.cooked.clone();
let command_path = quote!(crate::framework::Command);
populate_fut_lifetimes_on_refs(&mut fun.args);
let args = fun.args;
(quote! {
#(#cooked)*
pub static #n: #command_path = #command_path {
func: #name,
name: #lit_name,
required_perms: #permission_level,
supports_dm: #supports_dm,
can_blacklist: #can_blacklist,
};
#visibility fn #name<'fut> (#(#args),*) -> ::serenity::futures::future::BoxFuture<'fut, #ret> {
use ::serenity::futures::future::FutureExt;
async move { #(#body)* }.boxed()
}
})
.into()
}