WIP: use HdlOption[the_type_var] or UInt[123 + n] for creating types

crates/fayalite-proc-macros-impl/src/hdl_enum.rs

@@ -0,0 +1,657 @@
+use crate::{
+    hdl_type_common::{
+        common_derives, get_target, ItemOptions, MakeHdlTypeExpr, MaybeParsed, ParsedGenerics,
+        ParsedType, SplitForImpl, TypesParser, WrappedInConst,
+    },
+    Errors, HdlAttr, PairsIterExt,
+};
+use proc_macro2::TokenStream;
+use quote::{format_ident, quote_spanned, ToTokens};
+use syn::{
+    parse_quote_spanned,
+    punctuated::{Pair, Punctuated},
+    token::{Brace, Paren},
+    Attribute, Field, FieldMutability, Fields, FieldsNamed, FieldsUnnamed, Generics, Ident,
+    ItemEnum, ItemStruct, Token, Type, Variant, Visibility,
+};
+
+crate::options! {
+    #[options = VariantOptions]
+    pub(crate) enum VariantOption {}
+}
+
+crate::options! {
+    #[options = FieldOptions]
+    pub(crate) enum FieldOption {}
+}
+
+#[derive(Clone, Debug)]
+pub(crate) struct ParsedVariantField {
+    pub(crate) paren_token: Paren,
+    pub(crate) attrs: Vec<Attribute>,
+    pub(crate) options: HdlAttr<FieldOptions>,
+    pub(crate) ty: MaybeParsed<ParsedType, Type>,
+    pub(crate) comma_token: Option<Token![,]>,
+}
+
+#[derive(Clone, Debug)]
+pub(crate) struct ParsedVariant {
+    pub(crate) attrs: Vec<Attribute>,
+    pub(crate) options: HdlAttr<VariantOptions>,
+    pub(crate) ident: Ident,
+    pub(crate) field: Option<ParsedVariantField>,
+}
+
+impl ParsedVariant {
+    fn parse(
+        errors: &mut Errors,
+        variant: Variant,
+        generics: &MaybeParsed<ParsedGenerics, Generics>,
+    ) -> Self {
+        let Variant {
+            mut attrs,
+            ident,
+            fields,
+            discriminant,
+        } = variant;
+        let options = errors
+            .unwrap_or_default(HdlAttr::parse_and_take_attr(&mut attrs))
+            .unwrap_or_default();
+        let field = match fields {
+            Fields::Unnamed(FieldsUnnamed {
+                paren_token,
+                unnamed,
+            }) if unnamed.len() == 1 => {
+                let (field, comma_token) = unnamed.into_pairs().next().unwrap().into_tuple();
+                let Field {
+                    mut attrs,
+                    vis,
+                    mutability,
+                    ident: _,
+                    colon_token: _,
+                    ty,
+                } = field;
+                let options = errors
+                    .unwrap_or_default(HdlAttr::parse_and_take_attr(&mut attrs))
+                    .unwrap_or_default();
+                if !matches!(vis, Visibility::Inherited) {
+                    errors.error(
+                        &vis,
+                        "enum variant fields must not have a visibility specifier",
+                    );
+                }
+                if !matches!(mutability, FieldMutability::None) {
+                    // FIXME: use mutability as the spanned tokens,
+                    // blocked on https://github.com/dtolnay/syn/issues/1717
+                    errors.error(&ty, "field mutability is not supported");
+                }
+                Some(ParsedVariantField {
+                    paren_token,
+                    attrs,
+                    options,
+                    ty: TypesParser::maybe_run(generics.as_ref(), ty, errors),
+                    comma_token,
+                })
+            }
+            Fields::Unit => None,
+            Fields::Unnamed(fields) if fields.unnamed.is_empty() => None,
+            Fields::Named(fields) if fields.named.is_empty() => None,
+            Fields::Unnamed(_) | Fields::Named(_) => {
+                errors.error(
+                    fields,
+                    "enum variant must either have no fields or a single parenthesized field",
+                );
+                None
+            }
+        };
+        if let Some((eq, _)) = discriminant {
+            errors.error(eq, "custom enum discriminants are not allowed");
+        }
+        Self {
+            attrs,
+            options,
+            ident,
+            field,
+        }
+    }
+}
+
+#[derive(Clone, Debug)]
+pub(crate) struct ParsedEnum {
+    pub(crate) attrs: Vec<Attribute>,
+    pub(crate) options: HdlAttr<ItemOptions>,
+    pub(crate) vis: Visibility,
+    pub(crate) enum_token: Token![enum],
+    pub(crate) ident: Ident,
+    pub(crate) generics: MaybeParsed<ParsedGenerics, Generics>,
+    pub(crate) brace_token: Brace,
+    pub(crate) variants: Punctuated<ParsedVariant, Token![,]>,
+    pub(crate) match_variant_ident: Ident,
+}
+
+impl ParsedEnum {
+    fn parse(item: ItemEnum) -> syn::Result<Self> {
+        let ItemEnum {
+            mut attrs,
+            vis,
+            enum_token,
+            ident,
+            mut generics,
+            brace_token,
+            variants,
+        } = item;
+        let mut errors = Errors::new();
+        let mut options = errors
+            .unwrap_or_default(HdlAttr::<ItemOptions>::parse_and_take_attr(&mut attrs))
+            .unwrap_or_default();
+        errors.ok(options.body.validate());
+        let ItemOptions {
+            outline_generated: _,
+            connect_inexact: _,
+            target: _,
+            custom_bounds,
+            no_static: _,
+        } = options.body;
+        attrs.retain(|attr| {
+            if attr.path().is_ident("repr") {
+                errors.error(attr, "#[repr] is not supported on #[hdl] enums");
+                false
+            } else {
+                true
+            }
+        });
+        let generics = if custom_bounds.is_some() {
+            MaybeParsed::Unrecognized(generics)
+        } else if let Some(generics) = errors.ok(ParsedGenerics::parse(&mut generics)) {
+            MaybeParsed::Parsed(generics)
+        } else {
+            MaybeParsed::Unrecognized(generics)
+        };
+        let variants = Punctuated::from_iter(
+            variants
+                .into_pairs()
+                .map_pair_value(|v| ParsedVariant::parse(&mut errors, v, &generics)),
+        );
+        errors.finish()?;
+        Ok(Self {
+            attrs,
+            options,
+            vis,
+            enum_token,
+            generics,
+            brace_token,
+            variants,
+            match_variant_ident: format_ident!("__{}__MatchVariant", ident),
+            ident,
+        })
+    }
+}
+
+impl ToTokens for ParsedEnum {
+    fn to_tokens(&self, tokens: &mut TokenStream) {
+        let Self {
+            attrs,
+            options,
+            vis,
+            enum_token,
+            ident,
+            generics,
+            brace_token,
+            variants,
+            match_variant_ident,
+        } = self;
+        let ItemOptions {
+            outline_generated: _,
+            connect_inexact,
+            target,
+            custom_bounds: _,
+            no_static,
+        } = &options.body;
+        let target = get_target(target, ident);
+        let mut struct_attrs = attrs.clone();
+        struct_attrs.push(common_derives(ident.span()));
+        struct_attrs.push(parse_quote_spanned! {ident.span()=>
+            #[allow(non_snake_case)]
+        });
+        let struct_fields = Punctuated::from_iter(variants.pairs().map_pair_value_ref(
+            |ParsedVariant {
+                 attrs: _,
+                 options,
+                 ident,
+                 field,
+             }| {
+                let VariantOptions {} = options.body;
+                let colon_token;
+                let ty = if let Some(ParsedVariantField {
+                    paren_token,
+                    attrs: _,
+                    options,
+                    ty,
+                    comma_token: _,
+                }) = field
+                {
+                    let FieldOptions {} = options.body;
+                    colon_token = Token![:](paren_token.span.open());
+                    ty.clone().into()
+                } else {
+                    colon_token = Token![:](ident.span());
+                    parse_quote_spanned! {ident.span()=>
+                        ()
+                    }
+                };
+                Field {
+                    attrs: vec![],
+                    vis: vis.clone(),
+                    mutability: FieldMutability::None,
+                    ident: Some(ident.clone()),
+                    colon_token: Some(colon_token),
+                    ty,
+                }
+            },
+        ));
+        ItemStruct {
+            attrs: struct_attrs,
+            vis: vis.clone(),
+            struct_token: Token![struct](enum_token.span),
+            ident: ident.clone(),
+            generics: generics.into(),
+            fields: if struct_fields.is_empty() {
+                Fields::Unit
+            } else {
+                Fields::Named(FieldsNamed {
+                    brace_token: *brace_token,
+                    named: struct_fields,
+                })
+            },
+            semi_token: None,
+        }
+        .to_tokens(tokens);
+        let (impl_generics, type_generics, where_clause) = generics.split_for_impl();
+        if let MaybeParsed::Parsed(generics) = generics {
+            generics.make_runtime_generics(tokens, vis, ident, &target, |context| {
+                let fields: Vec<_> = variants
+                    .iter()
+                    .map(|ParsedVariant { ident, field, .. }| {
+                        if let Some(ParsedVariantField {
+                            ty: MaybeParsed::Parsed(ty),
+                            ..
+                        }) = field
+                        {
+                            let expr = ty.make_hdl_type_expr(context);
+                            quote_spanned! {ident.span()=>
+                                #ident: #expr,
+                            }
+                        } else {
+                            quote_spanned! {ident.span()=>
+                                #ident: (),
+                            }
+                        }
+                    })
+                    .collect();
+                parse_quote_spanned! {ident.span()=>
+                    #target {
+                        #(#fields)*
+                    }
+                }
+            })
+        }
+        let mut wrapped_in_const = WrappedInConst::new(tokens, ident.span());
+        let tokens = wrapped_in_const.inner();
+        {
+            let mut wrapped_in_const = WrappedInConst::new(tokens, ident.span());
+            let tokens = wrapped_in_const.inner();
+            let mut enum_attrs = attrs.clone();
+            enum_attrs.push(parse_quote_spanned! {ident.span()=>
+                #[allow(dead_code)]
+            });
+            ItemEnum {
+                attrs: enum_attrs,
+                vis: vis.clone(),
+                enum_token: *enum_token,
+                ident: ident.clone(),
+                generics: generics.into(),
+                brace_token: *brace_token,
+                variants: Punctuated::from_iter(variants.pairs().map_pair_value_ref(
+                    |ParsedVariant {
+                         attrs,
+                         options: _,
+                         ident,
+                         field,
+                     }| Variant {
+                        attrs: attrs.clone(),
+                        ident: ident.clone(),
+                        fields: match field {
+                            Some(ParsedVariantField {
+                                paren_token,
+                                attrs,
+                                options: _,
+                                ty,
+                                comma_token,
+                            }) => Fields::Unnamed(FieldsUnnamed {
+                                paren_token: *paren_token,
+                                unnamed: Punctuated::from_iter([Pair::new(
+                                    Field {
+                                        attrs: attrs.clone(),
+                                        vis: Visibility::Inherited,
+                                        mutability: FieldMutability::None,
+                                        ident: None,
+                                        colon_token: None,
+                                        ty: ty.clone().into(),
+                                    },
+                                    *comma_token,
+                                )]),
+                            }),
+                            None => Fields::Unit,
+                        },
+                        discriminant: None,
+                    },
+                )),
+            }
+            .to_tokens(tokens);
+        }
+        let mut enum_attrs = attrs.clone();
+        enum_attrs.push(parse_quote_spanned! {ident.span()=>
+            #[allow(dead_code, non_camel_case_types)]
+        });
+        ItemEnum {
+            attrs: enum_attrs,
+            vis: vis.clone(),
+            enum_token: *enum_token,
+            ident: match_variant_ident.clone(),
+            generics: generics.into(),
+            brace_token: *brace_token,
+            variants: Punctuated::from_iter(variants.pairs().map_pair_value_ref(
+                |ParsedVariant {
+                     attrs,
+                     options: _,
+                     ident,
+                     field,
+                 }| Variant {
+                    attrs: attrs.clone(),
+                    ident: ident.clone(),
+                    fields: match field {
+                        Some(ParsedVariantField {
+                            paren_token,
+                            attrs,
+                            options: _,
+                            ty,
+                            comma_token,
+                        }) => Fields::Unnamed(FieldsUnnamed {
+                            paren_token: *paren_token,
+                            unnamed: Punctuated::from_iter([Pair::new(
+                                Field {
+                                    attrs: attrs.clone(),
+                                    vis: Visibility::Inherited,
+                                    mutability: FieldMutability::None,
+                                    ident: None,
+                                    colon_token: None,
+                                    ty: parse_quote_spanned! {ident.span()=>
+                                        ::fayalite::expr::Expr<#ty>
+                                    },
+                                },
+                                *comma_token,
+                            )]),
+                        }),
+                        None => Fields::Unit,
+                    },
+                    discriminant: None,
+                },
+            )),
+        }
+        .to_tokens(tokens);
+        for (index, ParsedVariant { ident, field, .. }) in variants.iter().enumerate() {
+            if let Some(ParsedVariantField { ty, .. }) = field {
+                quote_spanned! {ident.span()=>
+                    #[automatically_derived]
+                    impl #impl_generics #target #type_generics
+                    #where_clause
+                    {
+                        #[allow(non_snake_case, dead_code)]
+                        #vis fn #ident<__V: ::fayalite::expr::ToExpr<Type = #ty>>(
+                            self,
+                            v: __V,
+                        ) -> ::fayalite::expr::Expr<Self> {
+                            ::fayalite::expr::ToExpr::to_expr(
+                                &::fayalite::expr::ops::EnumLiteral::new(
+                                    self,
+                                    #index,
+                                    ::fayalite::__std::option::Option::Some(
+                                        ::fayalite::expr::Expr::canonical(
+                                            ::fayalite::expr::ToExpr::to_expr(&v),
+                                        ),
+                                    ),
+                                ),
+                            )
+                        }
+                    }
+                }
+            } else {
+                quote_spanned! {ident.span()=>
+                    #[automatically_derived]
+                    impl #impl_generics #target #type_generics
+                    #where_clause
+                    {
+                        #[allow(non_snake_case, dead_code)]
+                        #vis fn #ident(self) -> ::fayalite::expr::Expr<Self> {
+                            ::fayalite::expr::ToExpr::to_expr(
+                                &::fayalite::expr::ops::EnumLiteral::new(
+                                    self,
+                                    #index,
+                                    ::fayalite::__std::option::Option::None,
+                                ),
+                            )
+                        }
+                    }
+                }
+            }
+            .to_tokens(tokens);
+        }
+        let from_canonical_body_fields = Vec::from_iter(variants.iter().enumerate().map(
+            |(index, ParsedVariant { ident, field, .. })| {
+                let ident_str = ident.to_string();
+                let val = if field.is_some() {
+                    let missing_value_msg = format!("expected variant {ident} to have a field");
+                    quote_spanned! {ident.span()=>
+                        ::fayalite::ty::Type::from_canonical(ty.expect(#missing_value_msg))
+                    }
+                } else {
+                    quote_spanned! {ident.span()=>
+                        ::fayalite::__std::assert!(ty.is_none());
+                    }
+                };
+                quote_spanned! {ident.span()=>
+                    #ident: {
+                        let ::fayalite::enum_::EnumVariant {
+                            name,
+                            ty,
+                        } = variants[#index];
+                        ::fayalite::__std::assert_eq!(&*name, #ident_str);
+                        #val
+                    },
+                }
+            },
+        ));
+        let match_active_scope_match_arms = Vec::from_iter(variants.iter().enumerate().map(
+            |(index, ParsedVariant { ident, field, .. })| {
+                if field.is_some() {
+                    quote_spanned! {ident.span()=>
+                        #index => #match_variant_ident::#ident(
+                            ::fayalite::expr::ToExpr::to_expr(
+                                &::fayalite::expr::ops::VariantAccess::new_unchecked(
+                                    variant_access.base(),
+                                    variant_access.variant_index(),
+                                ),
+                            ),
+                        ),
+                    }
+                } else {
+                    quote_spanned! {ident.span()=>
+                        #index => #match_variant_ident::#ident,
+                    }
+                }
+            },
+        ));
+        let variants_body_variants = Vec::from_iter(variants.iter().map(
+            |ParsedVariant {
+                 attrs: _,
+                 options,
+                 ident,
+                 field,
+             }| {
+                let VariantOptions {} = options.body;
+                let ident_str = ident.to_string();
+                match field {
+                    Some(ParsedVariantField { options, .. }) => {
+                        let FieldOptions {} = options.body;
+                        quote_spanned! {ident.span()=>
+                            ::fayalite::enum_::EnumVariant {
+                                name: ::fayalite::intern::Intern::intern(#ident_str),
+                                ty: ::fayalite::__std::option::Option::Some(
+                                    ::fayalite::ty::Type::canonical(&self.#ident),
+                                ),
+                            },
+                        }
+                    }
+                    None => quote_spanned! {ident.span()=>
+                        ::fayalite::enum_::EnumVariant {
+                            name: ::fayalite::intern::Intern::intern(#ident_str),
+                            ty: ::fayalite::__std::option::Option::None,
+                        },
+                    },
+                }
+            },
+        ));
+        let variants_len = variants.len();
+        quote_spanned! {ident.span()=>
+            #[automatically_derived]
+            impl #impl_generics ::fayalite::ty::Type for #target #type_generics
+            #where_clause
+            {
+                type BaseType = ::fayalite::enum_::Enum;
+                type MaskType = ::fayalite::int::Bool;
+                type MatchVariant = #match_variant_ident #type_generics;
+                type MatchActiveScope = ::fayalite::module::Scope;
+                type MatchVariantAndInactiveScope = ::fayalite::enum_::EnumMatchVariantAndInactiveScope<Self>;
+                type MatchVariantsIter = ::fayalite::enum_::EnumMatchVariantsIter<Self>;
+
+                fn match_variants(
+                    this: ::fayalite::expr::Expr<Self>,
+                    module_builder: &mut ::fayalite::module::ModuleBuilder<::fayalite::module::NormalModule>,
+                    source_location: ::fayalite::source_location::SourceLocation,
+                ) -> <Self as ::fayalite::ty::Type>::MatchVariantsIter {
+                    module_builder.enum_match_variants_helper(this, source_location)
+                }
+                fn mask_type(&self) -> <Self as ::fayalite::ty::Type>::MaskType {
+                    ::fayalite::int::Bool
+                }
+                fn canonical(&self) -> ::fayalite::ty::CanonicalType {
+                    ::fayalite::ty::CanonicalType::Enum(::fayalite::enum_::Enum::new(::fayalite::enum_::EnumType::variants(self)))
+                }
+                #[track_caller]
+                #[allow(non_snake_case)]
+                fn from_canonical(canonical_type: ::fayalite::ty::CanonicalType) -> Self {
+                    let ::fayalite::ty::CanonicalType::Enum(enum_) = canonical_type else {
+                        ::fayalite::__std::panic!("expected enum");
+                    };
+                    let variants = ::fayalite::enum_::EnumType::variants(&enum_);
+                    ::fayalite::__std::assert_eq!(variants.len(), #variants_len, "enum has wrong number of variants");
+                    Self {
+                        #(#from_canonical_body_fields)*
+                    }
+                }
+                fn source_location() -> ::fayalite::source_location::SourceLocation {
+                    ::fayalite::source_location::SourceLocation::caller()
+                }
+            }
+            #[automatically_derived]
+            impl #impl_generics ::fayalite::enum_::EnumType for #target #type_generics
+            #where_clause
+            {
+                fn match_activate_scope(
+                    v: <Self as ::fayalite::ty::Type>::MatchVariantAndInactiveScope,
+                ) -> (<Self as ::fayalite::ty::Type>::MatchVariant, <Self as ::fayalite::ty::Type>::MatchActiveScope) {
+                    let (variant_access, scope) = v.activate();
+                    (
+                        match variant_access.variant_index() {
+                            #(#match_active_scope_match_arms)*
+                            #variants_len.. => ::fayalite::__std::panic!("invalid variant index"),
+                        },
+                        scope,
+                    )
+                }
+                fn variants(&self) -> ::fayalite::intern::Interned<[::fayalite::enum_::EnumVariant]> {
+                    ::fayalite::intern::Intern::intern(&[
+                        #(#variants_body_variants)*
+                    ][..])
+                }
+            }
+        }
+        .to_tokens(tokens);
+        if let (None, MaybeParsed::Parsed(generics)) = (no_static, &self.generics) {
+            let static_generics = generics.clone().for_static_type();
+            let (static_impl_generics, static_type_generics, static_where_clause) =
+                static_generics.split_for_impl();
+            let static_type_body_variants =
+                Vec::from_iter(variants.iter().map(|ParsedVariant { ident, field, .. }| {
+                    if let Some(_) = field {
+                        quote_spanned! {ident.span()=>
+                            #ident: ::fayalite::ty::StaticType::TYPE,
+                        }
+                    } else {
+                        quote_spanned! {ident.span()=>
+                            #ident: (),
+                        }
+                    }
+                }));
+            let type_properties = format_ident!("__type_properties", span = ident.span());
+            let type_properties_variants =
+                Vec::from_iter(variants.iter().map(|ParsedVariant { ident, field, .. }| {
+                    let variant = if let Some(ParsedVariantField { ty, .. }) = field {
+                        quote_spanned! {ident.span()=>
+                            ::fayalite::__std::option::Option::Some(
+                                <#ty as ::fayalite::ty::StaticType>::TYPE_PROPERTIES,
+                            )
+                        }
+                    } else {
+                        quote_spanned! {ident.span()=>
+                            ::fayalite::__std::option::Option::None
+                        }
+                    };
+                    quote_spanned! {ident.span()=>
+                        let #type_properties = #type_properties.variant(#variant);
+                    }
+                }));
+            quote_spanned! {ident.span()=>
+                #[automatically_derived]
+                impl #static_impl_generics ::fayalite::ty::StaticType
+                for #target #static_type_generics
+                #static_where_clause
+                {
+                    const TYPE: Self = Self {
+                        #(#static_type_body_variants)*
+                    };
+                    const MASK_TYPE: <Self as ::fayalite::ty::Type>::MaskType =
+                        ::fayalite::int::Bool;
+                    const TYPE_PROPERTIES: ::fayalite::ty::TypeProperties = {
+                        let #type_properties = ::fayalite::enum_::EnumTypePropertiesBuilder::new();
+                        #(#type_properties_variants)*
+                        #type_properties.finish()
+                    };
+                    const MASK_TYPE_PROPERTIES: ::fayalite::ty::TypeProperties =
+                        <::fayalite::int::Bool as ::fayalite::ty::StaticType>::TYPE_PROPERTIES;
+                }
+            }
+            .to_tokens(tokens);
+        }
+    }
+}
+
+pub(crate) fn hdl_enum(item: ItemEnum) -> syn::Result<TokenStream> {
+    let item = ParsedEnum::parse(item)?;
+    let outline_generated = item.options.body.outline_generated;
+    let mut contents = item.to_token_stream();
+    if outline_generated.is_some() {
+        contents = crate::outline_generated(contents, "hdl-enum-");
+    }
+    Ok(contents)
+}