feat(specctra_derive): implement for enums containing unnamed fields

crates/specctra-core/src/error.rs

@@ -15,6 +15,8 @@ pub enum ParseError {
     Expected(&'static str),
     #[error("expected \"({0}\"")]
     ExpectedStartOfList(&'static str),
+    #[error("expected one of: {0:?}")]
+    ExpectedStartOfListOneOf(&'static [&'static str]),
     #[error("expected \")\"")]
     ExpectedEndOfList,
     #[error("expected leaf value")]

crates/specctra-core/src/structure.rs

@@ -279,8 +279,7 @@ pub struct Padstack {
     pub attach: Option<bool>,
 }
 
-// TODO: derive for enums if more than this single one is needed
-#[derive(Debug, Clone, PartialEq)]
+#[derive(ReadDsn, WriteSes, Debug, Clone, PartialEq)]
 pub enum Shape {
     Circle(Circle),
     Rect(Rect),
@@ -288,33 +287,6 @@ pub enum Shape {
     Polygon(Polygon),
 }
 
-impl<R: std::io::BufRead> ReadDsn<R> for Shape {
-    fn read_dsn(tokenizer: &mut ListTokenizer<R>) -> Result<Self, ParseErrorContext> {
-        let ctx = tokenizer.context();
-        let name = tokenizer.consume_token()?.expect_any_start()?;
-        let value = match name.as_str() {
-            "circle" => Ok(Shape::Circle(tokenizer.read_value()?)),
-            "rect" => Ok(Shape::Rect(tokenizer.read_value()?)),
-            "path" => Ok(Shape::Path(tokenizer.read_value()?)),
-            "polygon" => Ok(Shape::Polygon(tokenizer.read_value()?)),
-            _ => Err(ParseError::Expected("a different keyword").add_context(ctx)),
-        };
-        tokenizer.consume_token()?.expect_end()?;
-        value
-    }
-}
-
-impl<W: std::io::Write> WriteSes<W> for Shape {
-    fn write_dsn(&self, writer: &mut ListWriter<W>) -> Result<(), std::io::Error> {
-        match self {
-            Self::Circle(inner) => writer.write_named("circle", inner),
-            Self::Rect(inner) => writer.write_named("rect", inner),
-            Self::Path(inner) => writer.write_named("path", inner),
-            Self::Polygon(inner) => writer.write_named("polygon", inner),
-        }
-    }
-}
-
 #[derive(ReadDsn, WriteSes, Debug, Clone, PartialEq)]
 pub struct Circle {
     #[anon]

crates/specctra_derive/src/read.rs

@@ -6,7 +6,7 @@ use proc_macro2::TokenStream;
 use quote::quote;
 use syn::ext::IdentExt;
 use syn::Type::Path;
-use syn::{Data, DeriveInput, Field, Fields};
+use syn::{Data, DeriveInput, Field, Fields, Variant};
 
 use crate::parse_attributes;
 use crate::FieldType;
@@ -40,8 +40,19 @@ fn impl_body(data: &Data) -> TokenStream {
             }
             _ => unimplemented!(),
         },
-        Data::Enum(_data) => {
-            todo!();
+        Data::Enum(data) => {
+            let (variantnames, variants): (TokenStream, TokenStream) =
+                data.variants.iter().map(impl_variant).unzip();
+            quote! {
+                let ctx = tokenizer.context();
+                let name = tokenizer.consume_token()?.expect_any_start()?;
+                let value = Ok(match name.as_str() {
+                    #variants
+                    _ => return Err(ParseError::ExpectedStartOfListOneOf(&[#variantnames]).add_context(ctx)),
+                });
+                tokenizer.consume_token()?.expect_end()?;
+                value
+            }
         }
         _ => unimplemented!(),
     }
@@ -88,3 +99,35 @@ fn impl_field(field: &Field) -> TokenStream {
         }
     }
 }
+
+fn impl_variant(variant: &Variant) -> (TokenStream, TokenStream) {
+    let name = &variant.ident;
+    let mut name_str = name.unraw().to_string();
+    name_str.make_ascii_lowercase();
+
+    let inner = match &variant.fields {
+        Fields::Unnamed(fields) => {
+            let all_parts =
+                core::iter::repeat(quote! { tokenizer.read_value()?, }).take(fields.unnamed.len());
+            quote! { Self::#name(#(#all_parts)*) }
+        }
+        Fields::Named(fields) => {
+            let fields = fields.named.iter().map(impl_field);
+
+            quote! {
+                Self::#name {
+                    #(#fields)*
+                }
+            }
+        }
+        Fields::Unit => unimplemented!(),
+    };
+    (
+        quote! {
+            #name_str,
+        },
+        quote! {
+            #name_str => #inner,
+        },
+    )
+}

crates/specctra_derive/src/write.rs

@@ -2,11 +2,11 @@
 //
 // SPDX-License-Identifier: MIT
 
-use proc_macro2::TokenStream;
+use proc_macro2::{Span, TokenStream};
 use quote::quote;
 use syn::ext::IdentExt;
 use syn::Type::Path;
-use syn::{Data, DeriveInput, Field, Fields};
+use syn::{punctuated::Punctuated, Data, DeriveInput, Field, Fields, Ident, Variant};
 
 use crate::parse_attributes;
 use crate::FieldType;
@@ -41,6 +41,17 @@ fn impl_body(data: &Data) -> TokenStream {
             }
             _ => unimplemented!(),
         },
+        Data::Enum(data) => {
+            let variants = data.variants.iter().map(impl_variant);
+
+            quote! {
+                match self {
+                    #(#variants)*
+                }
+
+                Ok(())
+            }
+        }
         _ => unimplemented!(),
     }
 }
@@ -87,3 +98,30 @@ fn impl_field(field: &Field) -> TokenStream {
         }
     }
 }
+
+fn impl_variant(variant: &Variant) -> TokenStream {
+    let name = &variant.ident;
+    let mut name_str = name.unraw().to_string();
+    name_str.make_ascii_lowercase();
+
+    match &variant.fields {
+        Fields::Unnamed(fields) => {
+            let names: Vec<_> = (0..fields.unnamed.len())
+                .map(|i| Ident::new(&format!("inner__{}", i), Span::mixed_site()))
+                .collect();
+            let mut select = Punctuated::<_, syn::Token![,]>::new();
+            for i in &names {
+                select.push(i.clone());
+            }
+            let fields = names.into_iter().map(|name| {
+                quote! { writer.write_value(#name)?; }
+            });
+            quote! { Self::#name(#select) => {
+                writer.write_token(ListToken::Start { name: #name_str.to_string() })?;
+                #(#fields)*
+                writer.write_token(ListToken::End)?;
+            }, }
+        }
+        _ => unimplemented!(),
+    }
+}