use proc_macro::TokenStream;
use syn::parse::{Parse, ParseBuffer, ParseStream};
use syn::punctuated::Punctuated;
use syn::spanned::Spanned;
use syn::Token;
mod generator;
#[proc_macro]
pub fn derive(input: TokenStream) -> TokenStream {
let Args {
avx,
mut pairs,
print,
simd,
} = match syn::parse::<Builder>(input).and_then(Builder::build) {
Ok(s) => s,
Err(e) => return e.to_compile_error().into(),
};
pairs.sort_by_key(|p| p.ch);
for i in 0..pairs.len() - 1 {
let p1 = &pairs[i];
let p2 = &pairs[i + 1];
assert!(!(p1.ch == p2.ch), "{:?} and {:?} are repeated", p1, p2);
}
let code = generator::generate(&pairs, simd, avx);
if print {
eprintln!("{}", code);
}
code.parse().unwrap()
}
#[derive(Debug)]
pub(crate) struct Pair {
ch: u8,
quote: String,
}
impl Pair {
pub fn new<I: Into<String>>(ch: u8, quote: I) -> Self {
Pair {
ch,
quote: quote.into(),
}
}
}
struct Args {
pairs: Vec<Pair>,
avx: bool,
print: bool,
simd: bool,
}
struct MetaOpt<Lit: Parse> {
path: syn::Path,
_eq_token: Token![=],
lit: Lit,
}
impl<Lit: Parse> Parse for MetaOpt<Lit> {
fn parse<'a>(input: &'a ParseBuffer<'a>) -> syn::Result<Self> {
Ok(Self {
path: input.parse()?,
_eq_token: input.parse()?,
lit: input.parse()?,
})
}
}
struct Ch(u8);
impl Ch {
fn new(n: u8) -> Result<Self, ()> {
match n < (std::i8::MAX as u8) {
true => Ok(Ch(n)),
false => Err(()),
}
}
}
impl Parse for Ch {
fn parse(input: ParseStream) -> syn::Result<Self> {
use syn::Lit;
let lit: &Lit = &input.parse()?;
let map_err = |_: ()| syn::Error::new(lit.span(), "Only accept ASCII characters");
Ok(match lit {
Lit::Byte(v) => Ch::new(v.value()).map_err(map_err)?,
Lit::Char(v) => Ch::new(v.value() as u8).map_err(map_err)?,
Lit::Int(v) => v
.base10_parse::<i8>()
.map_err(|_| ())
.and_then(|x| Ch::new(x as u8))
.map_err(map_err)?,
_ => return Err(map_err(())),
})
}
}
struct PairBuilder {
ch: Ch,
_s: Token![->],
quote: syn::LitStr,
}
impl Parse for PairBuilder {
fn parse(input: ParseStream) -> syn::Result<Self> {
Ok(PairBuilder {
ch: input.parse()?,
_s: input.parse()?,
quote: input.parse()?,
})
}
}
struct Builder {
pairs: Punctuated<PairBuilder, Token![,]>,
_sep: Option<Token![;]>,
opts: Punctuated<MetaOpt<syn::LitBool>, Token![,]>,
}
impl Parse for Builder {
fn parse<'a>(input: &'a ParseBuffer<'a>) -> syn::Result<Self> {
Ok(Self {
pairs: Punctuated::parse_separated_nonempty(input)?,
_sep: input.parse()?,
opts: Punctuated::parse_terminated(input)?,
})
}
}
impl Builder {
fn build(self) -> syn::Result<Args> {
let Builder { pairs, opts, .. } = self;
let mut avx = true;
let mut print = false;
let mut simd = true;
for MetaOpt { path, lit, .. } in opts {
if path.is_ident("avx") {
avx = lit.value
} else if path.is_ident("print") {
print = lit.value;
} else if path.is_ident("simd") {
simd = lit.value;
} else {
return Err(syn::Error::new(
path.span(),
format!("invalid attribute '{:?}'", path.get_ident()),
));
}
}
Ok(Args {
pairs: pairs
.into_pairs()
.map(|x| x.into_value())
.map(|x| Pair::new(x.ch.0, x.quote.value()))
.collect(),
avx,
print,
simd,
})
}
}