Add derive macro to strip enum of data

quork-proc/Cargo.toml

@@ -20,3 +20,6 @@ proc-macro-error2 = "2.0"
 proc-macro2 = "1.0"
 quote = "1.0"
 syn = { version = "2.0", features = ["full"] }
+
+[dev-dependencies]
+strum = { version = "0.26", features = ["derive"] }

quork-proc/src/lib.rs

@@ -3,23 +3,34 @@
 #![warn(clippy::pedantic)]
 #![warn(missing_docs)]
 
+use proc_macro::TokenStream;
 use proc_macro_error2::proc_macro_error;
 use syn::{parse_macro_input, DeriveInput, LitStr};
 
 mod const_str;
 mod enum_list;
 mod from_tuple;
 mod new;
+mod strip_enum;
 mod time_fn;
 mod trim_lines;
 
 #[macro_use]
 extern crate quote;
 
+/// Create an additional enum with all values stripped
+#[proc_macro_derive(Strip, attributes(stripped_meta, stripped))]
+#[proc_macro_error]
+pub fn strip_enum(input: TokenStream) -> TokenStream {
+    let mut ast = parse_macro_input!(input as DeriveInput);
+
+    strip_enum::strip_enum(&mut ast).into()
+}
+
 /// Implement [`quork::ListVariants`] for enums
 #[proc_macro_derive(ListVariants)]
 #[proc_macro_error]
-pub fn derive_enum_list(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
+pub fn derive_enum_list(input: TokenStream) -> TokenStream {
     let ast = parse_macro_input!(input as DeriveInput);
     enum_list::enum_list(&ast).into()
 }
@@ -29,7 +40,7 @@ pub fn derive_enum_list(input: proc_macro::TokenStream) -> proc_macro::TokenStre
 ///
 /// Converts an enum variant to a string literal, within a constant context.
 #[proc_macro_derive(ConstStr)]
-pub fn derive_const_str(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
+pub fn derive_const_str(input: TokenStream) -> TokenStream {
     let ast = parse_macro_input!(input as DeriveInput);
     const_str::derive(&ast).into()
 }
@@ -39,15 +50,15 @@ pub fn derive_const_str(input: proc_macro::TokenStream) -> proc_macro::TokenStre
 /// Will follow the form of `new(field: Type, ...) -> Self`, where all fields are required.
 #[proc_macro_derive(New)]
 #[proc_macro_error]
-pub fn derive_new(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
+pub fn derive_new(input: TokenStream) -> TokenStream {
     let ast = parse_macro_input!(input as DeriveInput);
     new::derive(&ast).into()
 }
 
 /// Implement the [`std::convert::From`] trait for converting tuples into tuple structs
 #[proc_macro_derive(FromTuple)]
 #[proc_macro_error]
-pub fn derive_from_tuple(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
+pub fn derive_from_tuple(input: TokenStream) -> TokenStream {
     let ast = parse_macro_input!(input as DeriveInput);
     from_tuple::derive(&ast).into()
 }
@@ -59,10 +70,7 @@ pub fn derive_from_tuple(input: proc_macro::TokenStream) -> proc_macro::TokenStr
 /// You can pass "s", "ms", "ns"
 #[proc_macro_attribute]
 #[proc_macro_error]
-pub fn time(
-    args: proc_macro::TokenStream,
-    input: proc_macro::TokenStream,
-) -> proc_macro::TokenStream {
+pub fn time(args: TokenStream, input: TokenStream) -> TokenStream {
     let args_str = args.to_string();
     let fmt = match args_str.as_str() {
         "ms" | "milliseconds" => time_fn::TimeFormat::Milliseconds,
@@ -98,7 +106,6 @@ pub fn ltrim_lines(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
 
 /// Trim whitespace from the right of a string literal on each line
 #[proc_macro]
-#[deprecated = "Use trim_lines (renamed to avoid confusion)"]
 pub fn strip_lines(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
     let literal = parse_macro_input!(input as LitStr);
 
@@ -108,7 +115,7 @@ pub fn strip_lines(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
 /// Trim whitespace from the left and right of a string literal on each line
 #[proc_macro]
 #[deprecated = "Use rtrim_lines (renamed to avoid confusion)"]
-pub fn rstrip_lines(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
+pub fn rstrip_lines(input: TokenStream) -> proc_macro::TokenStream {
     let literal = parse_macro_input!(input as LitStr);
 
     trim_lines::trim_lines(&literal, &trim_lines::Alignment::Right).into()
@@ -117,7 +124,7 @@ pub fn rstrip_lines(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
 /// Trim whitespace from the left of a string literal on each line
 #[proc_macro]
 #[deprecated = "Use ltrim_lines (renamed to avoid confusion)"]
-pub fn lstrip_lines(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
+pub fn lstrip_lines(input: TokenStream) -> proc_macro::TokenStream {
     let literal = parse_macro_input!(input as LitStr);
 
     trim_lines::trim_lines(&literal, &trim_lines::Alignment::Left).into()

quork-proc/src/strip_enum.rs

@@ -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};
+
+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;
+
+            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)
+            };
+
+            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);
+
+                let mut new_ident: Option<Ident> = None;
+
+                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()
+            };
+
+            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;
+
+    // panic!("{:?}", meta);
+
+    quote! {
+        #(#[#meta])*
+        #vis enum #ident {
+            #(#variants),*
+        }
+    }
+}

quork-proc/tests/strip_enum.rs

@@ -0,0 +1,60 @@
+#![allow(dead_code)]
+
+use std::fmt::Display;
+
+use strum::{Display, EnumIter, IntoEnumIterator};
+
+use quork_proc::Strip;
+
+pub fn enum_to_string<T: IntoEnumIterator + Display>() -> String {
+    T::iter().map(|v| v.to_string()).collect::<String>()
+}
+
+struct DummyStruct;
+
+#[derive(Strip)]
+#[stripped_meta(derive(EnumIter, Display))]
+#[stripped_meta(strum(serialize_all = "kebab-case"))]
+enum EnumWithData {
+    Test1(DummyStruct),
+    Test2(DummyStruct),
+}
+
+#[test]
+fn has_all_variants() {
+    let variants = enum_to_string::<EnumWithDataStripped>();
+
+    assert_eq!(variants, "test1test2");
+}
+
+#[derive(Strip)]
+#[stripped_meta(derive(EnumIter, Display))]
+#[stripped_meta(strum(serialize_all = "kebab-case"))]
+enum EnumExclude {
+    Test1(DummyStruct),
+    #[stripped(ignore)]
+    Test2(DummyStruct),
+    Test3(DummyStruct),
+}
+
+#[derive(Strip)]
+#[stripped_meta(derive(EnumIter))]
+#[stripped_meta(strum(serialize_all = "kebab-case"))]
+enum EnumWithInherit {
+    Test1(DummyStruct),
+}
+
+#[derive(Strip)]
+#[stripped_meta(derive(EnumIter))]
+#[stripped_meta(strum(serialize_all = "kebab-case"))]
+#[stripped(ident = IChoseThisIdent)]
+enum EnumWithCustomIdent {
+    Test1(DummyStruct),
+}
+
+#[test]
+fn excludes_no_hook_variant() {
+    let variants = enum_to_string::<EnumExcludeStripped>();
+
+    assert_eq!(variants, "test1test3");
+}