quick arrays
support _
| -rw-r--r-- | Cargo.lock | 2 | ||||
| -rw-r--r-- | Cargo.toml | 2 | ||||
| -rw-r--r-- | src/lib.rs | 77 |
3 files changed, 59 insertions, 22 deletions
@@ -4,7 +4,7 @@ version = 4 [[package]] name = "amap" -version = "0.1.3" +version = "0.1.4" dependencies = [ "itertools", "proc-macro2", @@ -1,6 +1,6 @@ [package] name = "amap" -version = "0.1.3" +version = "0.1.4" authors = ["bend-n <[email protected]>"] description = "define `[Option<T>; N]` easily" edition = "2024" @@ -2,7 +2,7 @@ use itertools::Itertools; use proc_macro2::TokenStream; use quote::{ToTokens, quote}; use syn::{ - Error, Expr, Lit, Pat, PatConst, Stmt, Token, + Error, Expr, Lit, Pat, PatConst, PatWild, Stmt, Token, parse::{self, Parse, ParseStream}, parse_macro_input, punctuated::Punctuated, @@ -11,16 +11,32 @@ use syn::{ #[derive(Clone)] struct Index { - indices: Vec<Expr>, + indices: Indices, value: Expr, } -fn indices(index: &Pat) -> syn::Result<Vec<Expr>> { +#[derive(Clone)] +enum Indices { + Normal(Vec<Expr>), + Wild(PatWild), +} +fn indices(index: &Pat) -> syn::Result<Indices> { match index { Pat::Lit(v) => match &v.lit { Lit::Int(_) => Ok(vec![v.clone().into()]), _ => Err(Error::new_spanned(v, "must be numeric literal"))?, }, - Pat::Or(v) => v.cases.iter().map(indices).flatten_ok().collect(), + Pat::Or(v) => v + .cases + .iter() + .map(indices) + .map(|x| { + x.and_then(|x| match x { + Indices::Normal(x) => Ok(x), + Indices::Wild(x) => Err(Error::new_spanned(x, "cant have _ in |")), + }) + }) + .flatten_ok() + .collect(), Pat::Range(r) => { let s = r.span(); let r = r.clone(); @@ -71,11 +87,13 @@ fn indices(index: &Pat) -> syn::Result<Vec<Expr>> { }) }]) } + Pat::Wild(x) => return Ok(Indices::Wild(x.clone())), _ => Err(Error::new( index.span(), - "pattern must be literal(5) | or(5 | 4) | range(4..5) | const { .. }", + "pattern must be literal(5) | or(5 | 4) | range(4..5) | const { .. } | _", ))?, } + .map(Indices::Normal) } impl Parse for Index { @@ -103,28 +121,45 @@ impl Parse for Map { impl Map { fn into(self, d: TokenStream, f: impl Fn(&Expr) -> TokenStream + Copy) -> TokenStream { + let wild = self.0.iter().find_map(|x| match x.indices { + Indices::Normal(_) => None, + Indices::Wild(_) => Some(x.value.to_token_stream()), + }); + let w = wild.is_some(); let map = self .0 .into_iter() .zip(1..) .flat_map(|(Index { indices, value }, i)| { - indices.into_iter().map(move |x| { - let s = format!( - "duplicate / overlapping key @ pattern `{}` (#{i})", - x.to_token_stream() - .to_string() - .replace('{', "{{") - .replace('}', "}}") - ); - let value = f(&value); - quote! {{ - let (index, value) = { let (__ඞඞ, __set) = ((), ()); (#x, #value) }; - assert!(!__set[index], #s); - __set[index] = true; - __ඞඞ[index] = value; - }} + match indices { + Indices::Normal(x) => x, + _ => vec![], + } + .into_iter() + .map({ + move |x| { + let s = format!( + "duplicate / overlapping key @ pattern `{}` (#{i})", + x.to_token_stream() + .to_string() + .replace('{', "{{") + .replace('}', "}}") + ); + let value = if w { + value.to_token_stream() + } else { + f(&value) + }; + quote! {{ + let (index, value) = { let (__ඞඞ, __set) = ((), ()); (#x, #value) }; + assert!(!__set[index], #s); + __set[index] = true; + __ඞඞ[index] = value; + }} + } }) }); + let d = wild.unwrap_or(d); quote! {{ let mut __ඞඞ = [#d; _]; const fn steal<const N:usize, T>(_: &[T; N]) -> [bool; N] { [false; N] } @@ -154,6 +189,8 @@ impl Map { /// }; /// assert_eq!(X[44].as_ref().unwrap(), &Y::B); /// ``` +/// +/// Produces a `[T; N]` if a `_` branch is included. #[proc_macro] pub fn amap(input: proc_macro::TokenStream) -> proc_macro::TokenStream { parse_macro_input!(input as Map) |