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#![doc=include_str!("../README.md")]
mod int_range_ext;
mod util;
use util::RangeChecker;
use proc_macro::TokenStream;
use quote::{quote, ToTokens};
use syn::{parse_macro_input, spanned::Spanned, Error, ExprRange, ItemEnum, Meta, Type};
#[proc_macro_derive(IntType, attributes(default,))]
pub fn inttype(input: TokenStream) -> TokenStream {
let item = parse_macro_input!(input as ItemEnum);
let ident = &item.ident;
let Some(ty) = item.attrs.iter().find_map(|attr| {
let Meta::List(ref meta_list) = attr.meta else {
return None;
};
if !attr.path().is_ident("repr") {
return None;
}
syn::parse2::<Type>(meta_list.tokens.clone()).ok()
}) else {
// https://doc.rust-lang.org/reference/type-layout.html#primitive-representations
return Error::new(item.span(), "no #[repr(inttype)] provided.\n`inttype` can be one of `u8, u16, u32, u64, u128, usize, i8, i16, i32, i64, i128, and isize`.\n See https://doc.rust-lang.org/reference/type-layout.html#primitive-representations")
.into_compile_error().into();
};
let mut default_var = None;
let mut result = None;
let var = item
.variants
.iter()
.map(|v| {
if v.attrs.iter().any(|attr| attr.path().is_ident("default")) {
if default_var.is_some() {
result = Some(
Error::new(
v.span(),
"Multiple default variables supplied! should be only one!",
)
.into_compile_error(),
);
}
default_var = Some(&v.ident);
}
if !matches!(v.fields, syn::Fields::Unit) {
result = Some(
Error::new(v.span(), "every variant must be Unit kind, like `None`")
.into_compile_error(),
);
}
&v.ident
})
.collect::<Vec<_>>();
if let Some(ret) = result {
return ret.into();
}
let mut token_stream = quote! {
impl From<#ident> for #ty {
fn from(value: #ident) -> Self {
value as Self
}
}
};
let from = if let Some(default_var) = default_var {
quote! {
impl From<#ty> for #ident {
fn from(value: #ty) -> Self {
#![allow(non_upper_case_globals)]
#(
const #var: #ty = #ident::#var as #ty;
)*
match value {
#( #var => Self::#var, )*
_ => Self::#default_var,
}
}
}
}
} else {
quote! {
impl TryFrom<#ty> for #ident {
type Error = #ty;
fn try_from(value: #ty) -> Result<Self, Self::Error> {
#![allow(non_upper_case_globals)]
#(
const #var: #ty = #ident::#var as #ty;
)*
match value {
#( #var => Ok(Self::#var), )*
_ => Err(value)
}
}
}
}
};
token_stream.extend(from);
token_stream.into()
}
#[proc_macro_derive(IntRange, attributes(range,))]
pub fn new_inttype(input: TokenStream) -> TokenStream {
let item = parse_macro_input!(input as ItemEnum);
let ident = &item.ident;
let Some(ty) = item.attrs.iter().find_map(|attr| {
let Meta::List(ref meta_list) = attr.meta else {
return None;
};
if !attr.path().is_ident("repr") {
return None;
}
syn::parse2::<Type>(meta_list.tokens.clone()).ok()
}) else {
// https://doc.rust-lang.org/reference/type-layout.html#primitive-representations
return Error::new(item.span(), "no #[repr(inttype)] provided.\n`inttype` can be one of `u8, u16, u32, u64, u128, usize, i8, i16, i32, i64, i128, and isize`.\nSee https://doc.rust-lang.org/reference/type-layout.html#primitive-representations")
.into_compile_error().into();
};
let ty_str = ty.to_token_stream().to_string();
let mut checker = RangeChecker::new(ty_str.clone()).unwrap();
// let mut variants = Vec::with_capacity(item.variants.len());
let mut unit_variants = Vec::with_capacity(item.variants.len());
let mut unit_discriminant = Vec::with_capacity(item.variants.len());
let mut unnamed_variants = Vec::with_capacity(item.variants.len());
let mut unnamed_ranges = Vec::with_capacity(item.variants.len());
let mut ranges = Vec::with_capacity(item.variants.len());
for v in item.variants.iter() {
match &v.fields {
syn::Fields::Named(_) => {
return Error::new(
v.fields.span(),
"variant can only be Unit/Unamed kind, Examples: A=0,B(u8),",
)
.into_compile_error()
.into()
}
//#[repr(u8)] #[derive(IntType)] enum { #[range(1..5)]a(u8), }
syn::Fields::Unnamed(fields) => {
if fields.unnamed.len() != 1 {
return Error::new(
fields.span(),
format!(
"Unnamed variant can only have 1 field, here it must be {}",
ty.into_token_stream()
),
)
.into_compile_error()
.into();
}
if v.discriminant.is_some() {
return Error::new(
v.discriminant.as_ref().unwrap().1.span(),
"Unnamed variant can't have discriminant",
)
.into_compile_error()
.into();
}
for unamed in fields.unnamed.iter() {
if unamed.ty.to_token_stream().to_string() != ty_str {
return Error::new(
fields.span(),
format!(
"Unnamed variant's field must be the same type as its repr: {}",
ty.into_token_stream()
),
)
.into_compile_error()
.into();
}
}
let mut range_cnt = 0;
for attr in v.attrs.iter() {
if attr.path().is_ident("range") {
range_cnt += 1;
if range_cnt > 1 {
return Error::new(
attr.path().span(),
"Only one range attribute must be provided for Unnamed variant",
)
.into_compile_error()
.into();
}
let range: ExprRange = match attr.parse_args() {
Ok(r) => r,
Err(e) => return e.into_compile_error().into(),
};
// println!("cur ident: {}", v.ident.to_string());
// println!("range: {}", range.to_token_stream());
if let Err(e) = checker.substract(&range) {
return e.into_compile_error().into();
}
let inclusive_expr = checker.expr_to_inclusive_expr(&range).unwrap();
ranges.push(range);
unnamed_variants.push(&v.ident);
unnamed_ranges.push(inclusive_expr);
}
}
if range_cnt != 1 {
return Error::new(
fields.span(),
"one range attribute must be provided for Unnamed variant",
)
.into_compile_error()
.into();
}
}
//#[repr(u8)] #[derive(IntType)] enum { a=0, }
syn::Fields::Unit => {
if v.attrs.iter().any(|attr| attr.path().is_ident("range")) {
return Error::new(v.span(), "Unit variant should not have `range` attribute")
.into_compile_error()
.into();
}
// let s = v.ident.to_string();
// println!("v: {}", v.to_token_stream());
// println!("cur unit ident: {}", v.ident.to_string());
match v.discriminant.as_ref() {
Some((_, n)) => {
let s = n.to_token_stream().to_string();
let range =
syn::parse_str::<ExprRange>(format!("{}..={}", s, s).as_str()).unwrap();
if let Err(e) = checker.substract(&range) {
// println!("e.span(): {:?}", e.span());
return Error::new(n.span(), e.to_string())
.into_compile_error()
.into();
}
ranges.push(range);
unit_discriminant.push(n);
unit_variants.push(&v.ident);
}
None => {
return Error::new(v.span(), "must specify discriminant, like A=0")
.into_compile_error()
.into()
}
}
}
}
// println!("ident: {}", v.ident.to_string());
}
// println!("checker.is_empty(): {}", checker.is_empty());
// println!("ranges: {:?}", ranges.iter().map(|r| r.to_token_stream()).collect::<Vec<_>>());
// println!("ty: {}", ty.to_token_stream());
// println!("ident: {}", ident);
// println!("unit_variants: {:?}", unit_variants);
// println!("unit_discriminant: {:?}", unit_discriminant.iter().map(|r| r.to_token_stream()).collect::<Vec<_>>());
// println!("unnamed_variants: {:?}", unnamed_variants);
// println!("unnamed_ranges: {:?}", unnamed_ranges.iter().map(|r| r.to_token_stream()).collect::<Vec<_>>());
let mut token_stream = quote! {
impl From<#ident> for #ty {
fn from(value: #ident) -> Self {
match value {
#(
#ident::#unit_variants => #unit_discriminant,
)*
#(
#ident::#unnamed_variants(n) => n,
)*
}
}
}
// impl PartialEq<#ident> for #ty {
// fn eq(&self, other: &#ident) -> bool {
// match other {
// #(
// #ident::#unit_variants => #unit_discriminant == *self,
// )*
// #(
// #ident::#unnamed_variants(n) => *n == *self,
// )*
// }
// }
// }
// impl PartialEq<#ty> for #ident {
// fn eq(&self, other: &#ty) -> bool {
// match self {
// #(
// #ident::#unit_variants => #unit_discriminant == *other,
// )*
// #(
// #ident::#unnamed_variants(n) => *n == *other,
// )*
// }
// }
// }
impl #ident {
pub fn is_valid(&self) -> bool {
match self {
#(
Self::#unit_variants => true,
)*
#(
#[allow(unreachable_patterns)]
#[allow(non_contiguous_range_endpoints)]
Self::#unnamed_variants(n) => match n {
#unnamed_ranges => true,
_ => false,
},
)*
}
}
}
};
let ty_to_ident = if checker.is_empty() {
quote! {
impl From<#ty> for #ident {
fn from(value: #ty) -> Self {
match value {
#(
#unit_discriminant => Self::#unit_variants,
)*
#(
#unnamed_ranges => Self::#unnamed_variants(value),
)*
}
}
}
}
} else {
quote! {
impl TryFrom<#ty> for #ident {
type Error = #ty;
fn try_from(value: #ty) -> Result<Self, Self::Error> {
#[allow(unreachable_patterns)]
#[allow(non_contiguous_range_endpoints)]
match value {
#(
#unit_discriminant => Ok(Self::#unit_variants),
)*
#(
#unnamed_ranges => Ok(Self::#unnamed_variants(value)),
)*
_ => Err(value)
}
}
}
}
};
token_stream.extend(ty_to_ident);
token_stream.into()
}