add display attribute for Enum macro #1518

async-graphql · May 9, 2024 · a355af3 · a355af3
1 parent 733729a
commit a355af3
Show file tree

Hide file tree

Showing 4 changed files with 41 additions and 0 deletions.
diff --git a/derive/src/args.rs b/derive/src/args.rs
@@ -381,6 +381,8 @@ pub struct Enum {
     #[darling(default)]
     pub name: Option<String>,
     #[darling(default)]
+    pub display: bool,
+    #[darling(default)]
     pub name_type: bool,
     #[darling(default)]
     pub rename_items: Option<RenameRule>,

diff --git a/derive/src/enum.rs b/derive/src/enum.rs
@@ -41,6 +41,7 @@ pub fn generate(enum_args: &args::Enum) -> GeneratorResult<TokenStream> {
         .unwrap_or_else(|| quote! {::std::option::Option::None});
 
     let mut enum_items = Vec::new();
+    let mut enum_names = Vec::new();
     let mut items = Vec::new();
     let mut schema_enum_items = Vec::new();
 
@@ -75,6 +76,7 @@ pub fn generate(enum_args: &args::Enum) -> GeneratorResult<TokenStream> {
             .unwrap_or_else(|| quote! {::std::option::Option::None});
 
         enum_items.push(item_ident);
+        enum_names.push(gql_item_name.clone());
         items.push(quote! {
             #crate_name::resolver_utils::EnumItem {
                 name: #gql_item_name,
@@ -136,6 +138,25 @@ pub fn generate(enum_args: &args::Enum) -> GeneratorResult<TokenStream> {
         .into());
     }
 
+    let display = if enum_args.display {
+        let items = enum_items.iter().zip(&enum_names).map(|(item, name)| {
+            quote! {
+                #ident::#item => #name,
+            }
+        });
+        Some(quote! {
+            impl ::std::fmt::Display for #ident {
+                fn fmt(&self, f: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result {
+                    f.write_str(match self {
+                        #(#items)*
+                    })
+                }
+            }
+        })
+    } else {
+        None
+    };
+
     let visible = visible_fn(&enum_args.visible);
     let expanded = quote! {
         #[allow(clippy::all, clippy::pedantic)]
@@ -217,6 +238,7 @@ pub fn generate(enum_args: &args::Enum) -> GeneratorResult<TokenStream> {
         }
 
         #remote_conversion
+        #display
     };
     Ok(expanded.into())
 }
diff --git a/src/docs/enum.md b/src/docs/enum.md
@@ -8,6 +8,7 @@ Define a GraphQL enum
 |--------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------|----------|
 | name         | Enum name                                                                                                                                                                        | string | Y        |
 | name_type    | If `true`, the enum name will be specified from [`async_graphql::TypeName`](https://docs.rs/async-graphql/latest/async_graphql/trait.TypeName.html) trait                        | bool   | Y        |
+| display      | Implements `std::fmt::Display` for the enum type                                                                                                                                 | bool   | Y        |
 | rename_items | Rename all the fields according to the given case convention. The possible values are "lowercase", "UPPERCASE", "PascalCase", "camelCase", "snake_case", "SCREAMING_SNAKE_CASE". | string | Y        |
 | remote       | Derive a remote enum                                                                                                                                                             | string | Y        |
 | visible      | If `false`, it will not be displayed in introspection. *[See also the Book](https://async-graphql.github.io/async-graphql/en/visibility.html).*                                  | bool   | Y        |

diff --git a/tests/enum.rs b/tests/enum.rs
@@ -92,3 +92,19 @@ pub async fn test_remote_enum() {
     let _: remote::RemoteEnum = LocalEnum::A.into();
     let _: LocalEnum = remote::RemoteEnum::A.into();
 }
+
+#[tokio::test]
+pub async fn test_display() {
+    #[derive(Enum, Copy, Clone, Eq, PartialEq)]
+    #[graphql(display)]
+    enum MyEnum {
+        A,
+        #[graphql(name = "bbb")]
+        B,
+        C,
+    }
+
+    assert_eq!(MyEnum::A.to_string(), "A");
+    assert_eq!(MyEnum::B.to_string(), "bbb");
+    assert_eq!(MyEnum::C.to_string(), "C");
+}