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93 lines
3.1 KiB
Rust

use proc_macro2::{Ident, Span, TokenStream};
use proc_macro_crate::{crate_name, FoundCrate};
use quote::quote;
use syn::{parse::ParseStream, Error};
pub fn __make_absolute_path(name: &str, input: TokenStream) -> TokenStream {
match name {
// core and std are special because they don't appear in Cargo.toml
"core" => quote! { ::core #input },
"std" => quote! { ::std #input },
name => {
let prefix = match crate_name(name) {
Ok(found) => match found {
FoundCrate::Itself => quote! { crate },
FoundCrate::Name(name) => {
let name = Ident::new(&name, Span::call_site());
quote! { :: #name }
}
},
Err(e) => {
// proc_macro_crate failed to do its thing, so we try our best to
// not break other people's builds. Assume we're being called
// from another crate and the crate's author didn't rename us.
eprintln!("uwui_dsl: proc_macro_crate failed to resolve crate {name}, expect macro bugs!");
eprintln!("uwui_dsl: proc_macro_crate has this to say: \"{e}\"");
let name = Ident::new(name, Span::call_site());
quote! { :: #name }
}
};
quote! { #prefix #input }
}
}
}
macro_rules! absolute_path {
($crate_name:ident $(::$segment:ident)*) => {
$crate::util::__make_absolute_path(
stringify!($crate_name),
::quote::quote!($(::$segment)*)
)
};
}
pub(crate) use absolute_path;
macro_rules! use_absolute {
($($crate_name:ident $(::$path:ident)* as $name:ident),* $(,)?) => {
$(
#[allow(non_snake_case)]
let $name = $crate::util::absolute_path!($crate_name $(::$path)*);
)*
}
}
pub(crate) use use_absolute;
const RESERVED_IDENT_PREFIX: &str = "__uwui_";
pub fn make_reserved(name: &str, span: impl Into<Option<Span>>) -> Ident {
let span = span.into().unwrap_or_else(Span::call_site);
if name.starts_with(RESERVED_IDENT_PREFIX) {
Ident::new(name, span)
} else {
Ident::new(&format!("{RESERVED_IDENT_PREFIX}{name}"), span)
}
}
macro_rules! define_ident {
($($name:ident),* $(,)?) => {
$(
#[allow(non_snake_case)]
let $name = $crate::util::make_reserved(stringify!($name), None);
)*
}
}
pub(crate) use define_ident;
/// Recursively walk through a `ParseStream` and examine all identifiers.
/// Emit an error for any identifiers that start with [`RESERVED_IDENT_PREFIX`]
/// (`__uwui_`).
///
/// TODO: See if we can wrap ParseStream in a monad that does this check when
/// actually consuming the tokens
pub fn scan_for_reserved_idents(stream: ParseStream) -> syn::Result<ParseStream> {
let fork = stream.fork();
match scan_buf_for_ident_prefix(&fork, RESERVED_IDENT_PREFIX) {
Some(error) => Err(error),
None => Ok(stream),
}
}
fn scan_buf_for_ident_prefix(stream: ParseStream, prefix: &str) -> Option<Error> {
todo!()
}