Add derive macro for enums

Signed-off-by: trivernis <trivernis@protonmail.com>

derive/Cargo.toml

@@ -11,4 +11,7 @@ proc-macro = true
 [dependencies]
 proc-macro2 = "1.0.46"
 quote = "1.0.21"
-syn = "1.0.101"
+
+[dependencies.syn]
+version = "1"
+features = ["full"]

derive/src/lib.rs

@@ -1,8 +1,9 @@
 use proc_macro::TokenStream;
+use proc_macro2::Span;
 use quote::quote;
 use syn::{
-    parse_macro_input, parse_quote, DataStruct, DeriveInput, FieldsNamed, FieldsUnnamed, Generics,
-    WhereClause, WherePredicate,
+    parse_macro_input, parse_quote, DataEnum, DataStruct, DeriveInput, FieldsNamed, FieldsUnnamed,
+    Generics, Variant, WhereClause, WherePredicate,
 };
 
 #[proc_macro_derive(RustyValue)]
@@ -13,7 +14,7 @@ pub fn derive_value(input: TokenStream) -> TokenStream {
 fn derive(input: DeriveInput) -> TokenStream {
     match &input.data {
         syn::Data::Struct(s) => derive_struct(&input, s),
-        syn::Data::Enum(_) => todo!(),
+        syn::Data::Enum(e) => derive_enum(&input, e),
         syn::Data::Union(_) => panic!("unions are currently unsupported"),
     }
 }
@@ -45,7 +46,7 @@ fn derive_struct(input: &DeriveInput, struct_data: &DataStruct) -> TokenStream {
 
                         Value::Struct(Struct{
                             name: #name.to_string(),
-                            fields: StructFields::Named(values),
+                            fields: Fields::Named(values),
                         })
                     }
                 }
@@ -71,7 +72,7 @@ fn derive_struct(input: &DeriveInput, struct_data: &DataStruct) -> TokenStream {
 
                         Value::Struct(Struct{
                             name: #name.to_string(),
-                            fields: StructFields::Unnamed(values),
+                            fields: Fields::Unnamed(values),
                         })
                     }
                 }
@@ -80,13 +81,107 @@ fn derive_struct(input: &DeriveInput, struct_data: &DataStruct) -> TokenStream {
         syn::Fields::Unit => TokenStream::from(quote! {
                 impl #impl_generics rusty_value::RustyValue for #ident #ty_generics #where_clause {
                     fn into_rusty_value(self) -> rusty_value::Value {
-                        Value::Unit(#name.to_string())
+                        use rusty_value::*;
+                        Value::Struct(Struct{
+                            name: #name.to_string(),
+                            fields: Fields::Unit,
+                        })
                     }
                 }
         }),
     }
 }
 
+fn derive_enum(input: &DeriveInput, enum_data: &DataEnum) -> TokenStream {
+    let ident = &input.ident;
+    let (impl_generics, ty_generics, _) = input.generics.split_for_impl();
+    let where_clause = add_rusty_bound(&input.generics);
+    let variant_matchers = enum_data
+        .variants
+        .iter()
+        .map(|v| create_enum_value_match(ident, v))
+        .collect::<Vec<_>>();
+
+    TokenStream::from(quote! {
+        impl #impl_generics rusty_value::RustyValue for #ident #ty_generics #where_clause {
+            fn into_rusty_value(self) -> rusty_value::Value {
+                let enum_val = match self {
+                    #( #variant_matchers )*
+                };
+                rusty_value::Value::Enum(enum_val)
+            }
+        }
+    })
+}
+
+fn create_enum_value_match(ident: &syn::Ident, variant: &Variant) -> proc_macro2::TokenStream {
+    let enum_name = ident.to_string();
+    let variant_ident = &variant.ident;
+    let variant_name = variant_ident.to_string();
+
+    match &variant.fields {
+        syn::Fields::Named(FieldsNamed { named, .. }) => {
+            let field_idents = named.iter().map(|f| &f.ident).collect::<Vec<_>>();
+            let field_names = named
+                .iter()
+                .map(|f| f.ident.as_ref().unwrap().to_string())
+                .collect::<Vec<_>>();
+            let field_count = named.len();
+
+            quote! {
+                #ident::#variant_ident { #( #field_idents, )* } => {
+                    use rusty_value::*;
+
+                    let mut fields = std::collections::HashMap::with_capacity(#field_count);
+                    #(
+                        fields.insert(#field_names.to_string(), #field_idents.into_rusty_value());
+                    )*
+                    Enum {
+                        name: #enum_name.to_string(),
+                        variant: #variant_name.to_string(),
+                        fields: Fields::Named(fields)
+                    }
+                }
+            }
+        }
+        syn::Fields::Unnamed(FieldsUnnamed { unnamed, .. }) => {
+            let field_names = unnamed
+                .iter()
+                .enumerate()
+                .map(|(i, _)| syn::Ident::new(&format!("f{i}"), Span::call_site()))
+                .collect::<Vec<_>>();
+            let field_count = unnamed.len();
+
+            quote! {
+                #ident::#variant_ident ( #( #field_names, )* ) => {
+                    use rusty_value::*;
+
+                    let mut fields = Vec::with_capacity(#field_count);
+                    #(
+                        fields.push(#field_names.into_rusty_value());
+                    )*
+                    Enum {
+                        name: #enum_name.to_string(),
+                        variant: #variant_name.to_string(),
+                        fields: Fields::Unnamed(fields)
+                    }
+                }
+            }
+        }
+        syn::Fields::Unit => quote! {
+            #ident::#variant_ident => {
+                use rusty_value::*;
+
+                Enum {
+                    name: #enum_name.to_string(),
+                    variant: #variant_name.to_string(),
+                    fields: Fields::Unit
+                }
+            }
+        },
+    }
+}
+
 fn add_rusty_bound(generics: &Generics) -> WhereClause {
     let trait_bound: proc_macro2::TokenStream = parse_quote!(rusty_value::RustyValue);
 

src/value.rs

@@ -7,26 +7,26 @@ pub enum Value {
     Enum(Enum),
     Map(HashMap<HashablePrimitive, Value>),
     List(Vec<Value>),
-    Unit(String),
 }
 
 #[derive(Clone, Debug, PartialEq)]
 pub struct Enum {
     pub name: String,
     pub variant: String,
-    pub value: Box<Value>,
+    pub fields: Fields,
 }
 
 #[derive(Clone, Debug, PartialEq)]
 pub struct Struct {
     pub name: String,
-    pub fields: StructFields,
+    pub fields: Fields,
 }
 
 #[derive(Clone, Debug, PartialEq)]
-pub enum StructFields {
+pub enum Fields {
     Named(HashMap<String, Value>),
     Unnamed(Vec<Value>),
+    Unit,
 }
 
 #[derive(Clone, Debug, PartialEq, PartialOrd)]

tests/enums.rs

@@ -0,0 +1,138 @@
+use rusty_value::{Fields, RustyValue, Value};
+use rusty_value_derive::*;
+
+#[allow(dead_code)]
+#[derive(RustyValue)]
+enum TestEnumNamed {
+    Named { foo: String },
+    Named2 { foo: String, bar: u64 },
+}
+
+#[test]
+fn it_handles_enums_with_named_fields() {
+    let enum_value = TestEnumNamed::Named2 {
+        foo: String::from("hello"),
+        bar: 12,
+    };
+    let value = enum_value.into_rusty_value();
+    dbg!(&value);
+
+    if let Value::Enum(e) = value {
+        assert_eq!(&e.name, "TestEnumNamed");
+        assert_eq!(&e.variant, "Named2");
+
+        if let Fields::Named(n) = e.fields {
+            assert_eq!(n.len(), 2);
+        } else {
+            panic!("Enum variant doesn't have named fields")
+        }
+    } else {
+        panic!("Value is not an enum")
+    }
+}
+#[allow(dead_code)]
+#[derive(RustyValue)]
+enum TestEnumUnnamed {
+    Unnamed1(String, u8),
+    Unnamed2(u8),
+}
+
+#[test]
+fn it_handles_enums_with_unamed_fields() {
+    let enum_value = TestEnumUnnamed::Unnamed1(String::from("hello"), 12);
+    let value = enum_value.into_rusty_value();
+    dbg!(&value);
+
+    if let Value::Enum(e) = value {
+        assert_eq!(&e.name, "TestEnumUnnamed");
+        assert_eq!(&e.variant, "Unnamed1");
+
+        if let Fields::Unnamed(n) = e.fields {
+            assert_eq!(n.len(), 2);
+        } else {
+            panic!("Enum variant doesn't have unnamed fields")
+        }
+    } else {
+        panic!("Value is not an enum")
+    }
+}
+
+#[allow(dead_code)]
+#[derive(RustyValue)]
+enum TestEnumUnit {
+    Unit1,
+    Unit2,
+}
+
+#[test]
+fn it_handles_unit_enums() {
+    let enum_val = TestEnumUnit::Unit1;
+    let value = enum_val.into_rusty_value();
+    dbg!(&value);
+
+    if let Value::Enum(e) = value {
+        assert_eq!(&e.name, "TestEnumUnit");
+        assert_eq!(&e.variant, "Unit1");
+
+        if let Fields::Unit = e.fields {
+            assert!(true)
+        } else {
+            panic!("Enum is variant is not a unit")
+        }
+    } else {
+        panic!("Value is not an enum")
+    }
+}
+
+#[derive(RustyValue)]
+enum TestGeneric<R: Clone> {
+    CloneVar(R),
+}
+
+#[test]
+fn it_handles_generic_enums() {
+    let enum_val = TestGeneric::CloneVar(String::from("test"));
+    let value = enum_val.into_rusty_value();
+    dbg!(&value);
+
+    if let Value::Enum(e) = value {
+        assert_eq!(&e.name, "TestGeneric");
+        assert_eq!(&e.variant, "CloneVar");
+
+        if let Fields::Unnamed(u) = e.fields {
+            assert_eq!(u.len(), 1)
+        } else {
+            panic!("Enum is variant is not an unnamed enum")
+        }
+    } else {
+        panic!("Value is not an enum")
+    }
+}
+
+#[allow(dead_code)]
+#[derive(RustyValue)]
+enum TestMixed<R: Clone> {
+    CloneVar(R),
+    Unit,
+    Named { val: R, val2: u8 },
+}
+
+#[test]
+fn it_handles_mixed_enums() {
+    let enum_val = TestMixed::<String>::Unit;
+    let value = enum_val.into_rusty_value();
+    dbg!(&value);
+
+    if let Value::Enum(e) = value {
+        assert_eq!(&e.name, "TestMixed");
+        assert_eq!(&e.variant, "Unit");
+
+        if let Fields::Unit = e.fields {
+            assert!(true)
+        } else {
+            panic!("Enum is variant is not a unit")
+        }
+    } else {
+        panic!("Value is not an enum")
+    }
+}

tests/structs.rs

@@ -1,4 +1,4 @@
-use rusty_value::{RustyValue, StructFields, Value};
+use rusty_value::{Fields, RustyValue, Value};
 use rusty_value_derive::*;
 
 #[derive(RustyValue)]
@@ -19,7 +19,7 @@ fn it_handles_named_fields() {
     if let Value::Struct(s) = value {
         assert_eq!(&s.name, "TestStructNamed");
 
-        if let StructFields::Named(fields) = s.fields {
+        if let Fields::Named(fields) = s.fields {
             assert_eq!(fields.len(), 2);
         } else {
             panic!("Struct wasn't serialized as named struct")
@@ -41,7 +41,7 @@ fn it_handles_unnamed_fields() {
     if let Value::Struct(s) = value {
         assert_eq!(&s.name, "TestStructUnnamed");
 
-        if let StructFields::Unnamed(fields) = s.fields {
+        if let Fields::Unnamed(fields) = s.fields {
             assert_eq!(fields.len(), 2);
         } else {
             panic!("Struct wasn't serialized as unnamed struct")
@@ -60,8 +60,13 @@ fn it_handles_unit_structs() {
     let value = test_struct.into_rusty_value();
     dbg!(&value);
 
-    if let Value::Unit(s) = value {
-        assert_eq!(&s, "TestStructUnit");
+    if let Value::Struct(s) = value {
+        assert_eq!(&s.name, "TestStructUnit");
+        if let Fields::Unit = s.fields {
+            assert!(true);
+        } else {
+            panic!("Struct wasn't serialized as unit struct")
+        }
     } else {
         panic!("Struct wasn't serialized as struct");
     }
@@ -81,7 +86,7 @@ fn it_handles_generics() {
     if let Value::Struct(s) = value {
         assert_eq!(&s.name, "GenericStruct");
 
-        if let StructFields::Named(fields) = s.fields {
+        if let Fields::Named(fields) = s.fields {
             assert_eq!(fields.len(), 1);
         } else {
             panic!("Struct wasn't serialized as named struct")