Add Kind trait

Author: greyblake

README.md

@@ -62,14 +62,12 @@ impl Kinded for Drink {
 
 The `Kinded` trait allows to build abstract functions that can be used with different enum types.
 
-## Iterating
+## Get all kind variants
 
-The kind type gets implementation of `::all()` associated function, which returns an iterator over all kind variants.
-For example:
+The kind type gets implementation of `::all()` associated function, which returns a vector with all kind variants:
 
 ```rs
-let all_drink_kinds: Vec<_> = DrinkKind::all().collect();
-assert_eq!(all_drink_kinds, vec![DrinkKind::Mate, DrinkKind::Coffee, DrinkKind::Tea]);
+assert_eq!(DrinkKind::all(), vec![DrinkKind::Mate, DrinkKind::Coffee, DrinkKind::Tea]);
 ```
 
 

kinded/src/lib.rs

@@ -61,10 +61,9 @@
 //!
 //! The `Kinded` trait allows to build abstract functions that can be used with different enum types.
 //!
-//! ## Iterating
+//! ## Get all kind variants
 //!
-//! The kind type gets implementation of `::all()` associated function, which returns an iterator over all kind variants.
-//! For example:
+//! The kind type gets implementation of `::all()` associated function, which returns a vector with all kind variants:
 //!
 //! ```
 //! use kinded::Kinded;
@@ -76,8 +75,7 @@
 //!     Tea { variety: String, caffeine: bool }
 //! }
 //!
-//! let all_drink_kinds: Vec<_> = DrinkKind::all().collect();
-//! assert_eq!(all_drink_kinds, vec![DrinkKind::Mate, DrinkKind::Coffee, DrinkKind::Tea]);
+//! assert_eq!(DrinkKind::all(), vec![DrinkKind::Mate, DrinkKind::Coffee, DrinkKind::Tea]);
 //! ```
 //!
 //! ## Attributes
@@ -194,4 +192,4 @@ mod traits;
 
 pub use errors::ParseKindError;
 pub use kinded_macros::Kinded;
-pub use traits::Kinded;
+pub use traits::{Kinded, Kind};

kinded/src/traits.rs

@@ -3,7 +3,13 @@ use ::core::fmt::Debug;
 /// A trait that can be implemented by a main enum type.
 /// Typically should be derived with `#[derive(kinded::Kinded)]`.
 pub trait Kinded {
-    type Kind: PartialEq + Eq + Debug + Clone + Copy;
+    type Kind: PartialEq + Eq + Debug + Clone + Copy + Kind;
 
+    /// Get a kind variant without data.
     fn kind(&self) -> Self::Kind;
 }
+
+pub trait Kind: PartialEq + Eq + Debug + Clone + Copy {
+    /// Return a vector with all possible kind variants.
+    fn all() -> Vec<Self>;
+}

kinded_macros/src/gen/kind_enum.rs

@@ -7,12 +7,14 @@ pub fn gen_kind_enum(meta: &Meta) -> TokenStream {
     let impl_from_traits = gen_impl_from_traits(meta);
     let impl_display_trait = gen_impl_display_trait(meta);
     let impl_from_str_trait = gen_impl_from_str_trait(meta);
+    let impl_kind_trait = gen_impl_kind_trait(meta);
 
     quote!(
         #kind_enum_definition
         #impl_from_traits
         #impl_display_trait
         #impl_from_str_trait
+        #impl_kind_trait
     )
 }
 
@@ -29,10 +31,10 @@ fn gen_definition(meta: &Meta) -> TokenStream {
         }                                                                      // }
 
         impl #kind_name {                                                      // impl DrinkKind {
-            pub fn all() -> impl Iterator<Item = #kind_name> {                 //     pub fn all() -> impl Iterator<Item = DrinkKind> {
-                [                                                              //         [
+            pub fn all() -> Vec<#kind_name> {                                  //     pub fn all() -> Vec<DrinkKind> {
+                vec![                                                          //         vec![
                     #(#kind_name::#variant_names),*                            //             DrinkKind::Mate, DrinkKind::Coffee, DrinkKind::Tea
-                ].into_iter()                                                  //         ]
+                ]                                                              //         ]
             }                                                                  //     }
         }                                                                      // }
     )
@@ -131,3 +133,15 @@ fn gen_impl_from_str_trait(meta: &Meta) -> TokenStream {
         }
     )
 }
+
+fn gen_impl_kind_trait(meta: &Meta) -> TokenStream {
+    let kind_name = meta.kind_name();
+
+    quote!(
+        impl ::kinded::Kind for #kind_name {
+            fn all() -> Vec<#kind_name> {
+                Self::all()
+            }
+        }
+    )
+}

test_suite/src/lib.rs

@@ -13,7 +13,7 @@ enum Role {
     },
 }
 
-mod base_enum {
+mod main_enum {
     use super::*;
 
     mod fn_kind {
@@ -271,13 +271,26 @@ mod kind_enum {
                 assert_eq!("MySQL".parse::<DbKind>().unwrap(), DbKind::MySQL);
             }
         }
+
+        mod kind_trait {
+            use crate::RoleKind;
+
+            fn get_all_kinds<T: kinded::Kind>() -> Vec<T> {
+                T::all()
+            }
+
+            #[test]
+            fn should_implement_kind_trait() {
+                let kinds = get_all_kinds::<RoleKind>();
+                assert_eq!(kinds, vec![RoleKind::Guest, RoleKind::User, RoleKind::Admin])
+            }
+        }
     }
 
     #[test]
     fn should_provide_all_function_that_returns_iterator() {
-        let kinds: Vec<_> = RoleKind::all().collect();
         assert_eq!(
-            kinds,
+            RoleKind::all(),
             vec![RoleKind::Guest, RoleKind::User, RoleKind::Admin],
         )
     }