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extern crate proc_macro;
extern crate proc_macro2;
extern crate syn;
#[macro_use]
extern crate quote;
use proc_macro::TokenStream;
use proc_macro2::Span;
use syn::*;
mod config;
mod endian;
mod enums;
mod gen;
mod meta;
mod parsertree;
mod structs;
use crate::config::Config;
use crate::endian::{set_object_endianness, ParserEndianness};
use crate::gen::*;
use crate::meta::attr::{MetaAttr, MetaAttrType};
use enums::impl_nom_enums;
use structs::{get_pre_post_exec, parse_struct};
#[proc_macro_derive(Nom, attributes(nom))]
pub fn nom(input: TokenStream) -> TokenStream {
let ast = parse_macro_input!(input as DeriveInput);
match impl_nom(&ast, false, ParserEndianness::Unspecified) {
Ok(ts) => ts,
Err(e) => e.to_compile_error().into(),
}
}
#[proc_macro_derive(NomBE, attributes(nom))]
pub fn nom_be(input: TokenStream) -> TokenStream {
let ast = parse_macro_input!(input as DeriveInput);
match impl_nom(&ast, false, ParserEndianness::BigEndian) {
Ok(ts) => ts,
Err(e) => e.to_compile_error().into(),
}
}
#[proc_macro_derive(NomLE, attributes(nom))]
pub fn nom_le(input: TokenStream) -> TokenStream {
let ast = parse_macro_input!(input as DeriveInput);
match impl_nom(&ast, false, ParserEndianness::LittleEndian) {
Ok(ts) => ts,
Err(e) => e.to_compile_error().into(),
}
}
pub(crate) fn get_extra_args(meta_list: &[MetaAttr]) -> Option<&proc_macro2::TokenStream> {
meta_list
.iter()
.find(|m| m.attr_type == MetaAttrType::ExtraArgs)
.and_then(MetaAttr::arg)
}
fn impl_nom(
ast: &syn::DeriveInput,
debug_derive: bool,
endianness: ParserEndianness,
) -> Result<TokenStream> {
let struct_name = ast.ident.to_string();
let meta = meta::parse_nom_top_level_attribute(&ast.attrs)?;
let mut config = Config::from_meta_list(struct_name, &meta)?;
config.debug_derive |= debug_derive;
set_object_endianness(ast.ident.span(), endianness, &meta, &mut config)?;
let (tl_pre, tl_post) = get_pre_post_exec(&meta, &config);
let s = match &ast.data {
syn::Data::Enum(_) => {
return impl_nom_enums(ast, &mut config);
}
syn::Data::Struct(ref s) => parse_struct(s, &mut config)?,
syn::Data::Union(_) => panic!("Unions not supported"),
};
let generics = &ast.generics;
let name = &ast.ident;
let (idents, parser_tokens): (Vec<_>, Vec<_>) = s
.parsers
.iter()
.map(|sp| {
let id = syn::Ident::new(&sp.name, Span::call_site());
(id, &sp.item)
})
.unzip();
let (pre, post): (Vec<_>, Vec<_>) = s
.parsers
.iter()
.map(|sp| (sp.pre_exec.as_ref(), sp.post_exec.as_ref()))
.unzip();
let idents2 = idents.clone();
let struct_def = match (s.empty, s.unnamed) {
(true, _) => quote! { ( #name ) },
(_, true) => quote! { ( #name ( #(#idents2),* ) ) },
(_, false) => quote! { ( #name { #(#idents2),* } ) },
};
let input_name = syn::Ident::new(&config.input_name, Span::call_site());
let orig_input_name = get_orig_input_name(&config);
let extra_args = get_extra_args(&meta);
let fn_body = quote! {
let #input_name = #orig_input_name;
#tl_pre
#(#pre let (#input_name, #idents) = #parser_tokens (#input_name) ?; #post)*
let struct_def = #struct_def;
#tl_post
Ok((#input_name, struct_def))
};
let fn_decl = gen_fn_decl(generics, extra_args, &config);
let (impl_generics, ty_generics, where_clause) = generics.split_for_impl();
let impl_tokens = quote! {
impl #impl_generics #name #ty_generics #where_clause {
#fn_decl
{
#fn_body
}
}
};
if config.debug_derive {
eprintln!("tokens:\n{}", impl_tokens);
}
Ok(impl_tokens.into())
}
#[deprecated(
since = "0.6.0",
note = "Please use the nom(DebugDerive) attribute instead"
)]
#[proc_macro_derive(NomDeriveDebug, attributes(nom))]
pub fn nom_derive_debug(input: TokenStream) -> TokenStream {
let ast = parse_macro_input!(input as DeriveInput);
match impl_nom(&ast, true, ParserEndianness::Unspecified) {
Ok(ts) => ts,
Err(e) => e.to_compile_error().into(),
}
}