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Merge pull request #39 from jewlexx/strip-enum
Add derive macro to strip enum of data
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,172 @@ | ||
| use proc_macro2::{Ident, TokenStream}; | ||
| use proc_macro_error2::{abort, abort_call_site}; | ||
| use quote::{quote, ToTokens}; | ||
| use syn::{spanned::Spanned, DeriveInput, Meta, Variant, Visibility}; | ||
|
|
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| fn ignore_variant(variant: &Variant) -> bool { | ||
| variant.attrs.iter().any(|attr| match attr.meta { | ||
| syn::Meta::List(ref list) if list.path.is_ident("stripped") => { | ||
| let mut ignored = false; | ||
|
|
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| let list_parser = syn::meta::parser(|meta| { | ||
| if meta.path.is_ident("ignore") { | ||
| ignored = true; | ||
| Ok(()) | ||
| } else { | ||
| Err(meta.error("unsupported property")) | ||
| } | ||
| }); | ||
|
|
||
| if let Err(err) = list.parse_args_with(list_parser) { | ||
| abort! { | ||
| err.span(), | ||
| "Failed to parse attribute: {}", err; | ||
| help = "Only supported properties on enum variants are `ignore`" | ||
| } | ||
| } | ||
|
|
||
| ignored | ||
| } | ||
| _ => abort!( | ||
| attr.span(), | ||
| "Expected list-style (i.e #[stripped(...)]), found other style attribute macro" | ||
| ), | ||
| }) | ||
| } | ||
|
|
||
| struct StrippedData { | ||
| ident: Ident, | ||
| variants: Vec<TokenStream>, | ||
| meta: Vec<Meta>, | ||
| vis: Visibility, | ||
| } | ||
|
|
||
| // struct MetaArgs { | ||
| // meta: Vec<Expr>, | ||
| // } | ||
|
|
||
| // impl Parse for MetaArgs { | ||
| // fn parse(input: syn::parse::ParseStream) -> syn::Result<Self> { | ||
| // input.peek3(token) | ||
| // } | ||
| // } | ||
|
|
||
| pub fn strip_enum(ast: &mut DeriveInput) -> TokenStream { | ||
| let data = &ast.data; | ||
| let attrs = &mut ast.attrs; | ||
|
|
||
| let info: StrippedData = match data { | ||
| syn::Data::Enum(ref e) => { | ||
| let variants = e | ||
| .variants | ||
| .iter() | ||
| .filter_map(|variant| { | ||
| if ignore_variant(variant) { | ||
| None | ||
| } else { | ||
| Some(variant.ident.to_token_stream()) | ||
| } | ||
| }) | ||
| .collect::<Vec<_>>(); | ||
|
|
||
| let default_ident = { | ||
| let ident = ast.ident.clone(); | ||
| let span = ident.span(); | ||
| move || Ident::new(&format!("{ident}Stripped"), span) | ||
| }; | ||
|
|
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| let new_ident = if let Some(info_attr_pos) = attrs | ||
| .iter() | ||
| .position(|attr| attr.path().is_ident("stripped")) | ||
| { | ||
| let info_attr = attrs.remove(info_attr_pos); | ||
|
|
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| let mut new_ident: Option<Ident> = None; | ||
|
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| let ident_parser = syn::meta::parser(|meta| { | ||
| if meta.path.is_ident("ident") { | ||
| new_ident = Some(meta.value()?.parse()?); | ||
| Ok(()) | ||
| } else { | ||
| Err(meta.error("unsupported property")) | ||
| } | ||
| }); | ||
|
|
||
| if let Err(err) = info_attr.parse_args_with(ident_parser) { | ||
| abort! { | ||
| err.span(), | ||
| "Failed to parse attribute: {}", err; | ||
| help = "Only supported properties on enum definitions are `ident`" | ||
| } | ||
| } | ||
|
|
||
| new_ident.unwrap_or_else(default_ident) | ||
| } else { | ||
| default_ident() | ||
| }; | ||
|
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||
| let meta_list: Vec<syn::Meta> = attrs | ||
| .iter() | ||
| .filter(|attr| attr.path().is_ident("stripped_meta")) | ||
| .flat_map(|meta_attr| match &meta_attr.meta { | ||
| Meta::List(meta_data) => match meta_data.parse_args::<syn::Meta>() { | ||
| Ok(meta) => vec![meta], | ||
| Err(err) => { | ||
| abort! { | ||
| err.span(), | ||
| "Failed to parse specified metadata: {}", err; | ||
| help = "Make sure the provided arguments are in the form of Rust metadata. (i.e the tokens contained within `#[...]`)" | ||
| } | ||
| } | ||
| }, | ||
| // Meta::NameValue(MetaNameValue { | ||
| // value: | ||
| // syn::Expr::Lit(syn::ExprLit { | ||
| // lit: syn::Lit::Str(path), | ||
| // .. | ||
| // }), | ||
| // .. | ||
| // }) => { | ||
| // if &path.value() == "inherit" { | ||
| // attrs | ||
| // .iter() | ||
| // .filter(|attr| !attr.path().is_ident("stripped_meta")) | ||
| // .map(|attr| attr.meta.clone()) | ||
| // .collect() | ||
| // } else { | ||
| // abort!(path.span(), "Expected `inherit`"); | ||
| // } | ||
| // } | ||
| _ => abort!( | ||
| meta_attr.span(), | ||
| "Expected #[stripped_meta(...)]. Found other style attribute." | ||
| ), | ||
| }) | ||
| .collect(); | ||
|
|
||
| StrippedData { | ||
| ident: new_ident, | ||
| variants, | ||
| meta: meta_list, | ||
| vis: ast.vis.clone(), | ||
| } | ||
| } | ||
| _ => abort_call_site!("`Strip` can only be derived for enums"), | ||
| }; | ||
|
|
||
| let StrippedData { | ||
| ident, | ||
| variants, | ||
| meta, | ||
| vis, | ||
| } = info; | ||
|
|
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| // panic!("{:?}", meta); | ||
|
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||
| quote! { | ||
| #(#[#meta])* | ||
| #vis enum #ident { | ||
| #(#variants),* | ||
| } | ||
| } | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,60 @@ | ||
| #![allow(dead_code)] | ||
|
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| use std::fmt::Display; | ||
|
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| use strum::{Display, EnumIter, IntoEnumIterator}; | ||
|
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| use quork_proc::Strip; | ||
|
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| pub fn enum_to_string<T: IntoEnumIterator + Display>() -> String { | ||
| T::iter().map(|v| v.to_string()).collect::<String>() | ||
| } | ||
|
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| struct DummyStruct; | ||
|
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| #[derive(Strip)] | ||
| #[stripped_meta(derive(EnumIter, Display))] | ||
| #[stripped_meta(strum(serialize_all = "kebab-case"))] | ||
| enum EnumWithData { | ||
| Test1(DummyStruct), | ||
| Test2(DummyStruct), | ||
| } | ||
|
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| #[test] | ||
| fn has_all_variants() { | ||
| let variants = enum_to_string::<EnumWithDataStripped>(); | ||
|
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| assert_eq!(variants, "test1test2"); | ||
| } | ||
|
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| #[derive(Strip)] | ||
| #[stripped_meta(derive(EnumIter, Display))] | ||
| #[stripped_meta(strum(serialize_all = "kebab-case"))] | ||
| enum EnumExclude { | ||
| Test1(DummyStruct), | ||
| #[stripped(ignore)] | ||
| Test2(DummyStruct), | ||
| Test3(DummyStruct), | ||
| } | ||
|
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| #[derive(Strip)] | ||
| #[stripped_meta(derive(EnumIter))] | ||
| #[stripped_meta(strum(serialize_all = "kebab-case"))] | ||
| enum EnumWithInherit { | ||
| Test1(DummyStruct), | ||
| } | ||
|
|
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| #[derive(Strip)] | ||
| #[stripped_meta(derive(EnumIter))] | ||
| #[stripped_meta(strum(serialize_all = "kebab-case"))] | ||
| #[stripped(ident = IChoseThisIdent)] | ||
| enum EnumWithCustomIdent { | ||
| Test1(DummyStruct), | ||
| } | ||
|
|
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| #[test] | ||
| fn excludes_no_hook_variant() { | ||
| let variants = enum_to_string::<EnumExcludeStripped>(); | ||
|
|
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| assert_eq!(variants, "test1test3"); | ||
| } |