refactor(ecs): replace Pair ctor functions with builder

1 files changed, 61 insertions, 0 deletions

diff --git a/ecs/src/util.rs b/ecs/src/util.rs
index 9ab4dc6..2ab78cd 100644
--- a/ecs/src/util.rs
+++ b/ecs/src/util.rs
@@ -300,6 +300,67 @@ macro_rules! gen_mask_64 {
 
 pub(crate) use gen_mask_64;
 
+macro_rules! impl_multiple {
+    (
+        $type: ident,
+        ($(impl$(<$($generic: tt$(: $bound: ident)?),*>)? _<$($type_param: ty),*>),*)
+        ($($ty_param_matcher: ident),*) => {
+            $($item_tt: tt)*
+        }
+    ) => {
+        const _: () = {
+            $crate::util::impl_multiple!(
+                @(make_gen_item_macro)
+                _gen_multiple_impl_item,
+                ($($ty_param_matcher),*),
+                ($($item_tt)*)
+            );
+
+            $(
+                impl $(<$($generic$(: $bound)?,)*>)? $type<$($type_param),*>
+                {
+                    _gen_multiple_impl_item!($($type_param),*);
+                }
+            )*
+        };
+    };
+
+    (
+        @(make_gen_item_macro)
+        $name: ident,
+        ($($ty_param_matcher: ident),*),
+        ($($transcriber: tt)*)
+    ) => {
+        $crate::util::impl_multiple!(
+            @(make_gen_item_macro)
+            ($), $name, ($($ty_param_matcher),*), ($($transcriber)*)
+        );
+    };
+
+    (
+        @(make_gen_item_macro)
+        ($dollar: tt),
+        $name: ident,
+        ($($ty_param_matcher: ident),*),
+        ($($transcriber: tt)*)
+    ) => {
+        $crate::util::impl_multiple!(
+            @(make_gen_item_macro)
+            $name, ($($dollar$ty_param_matcher: ty),*) => {
+                $($transcriber)*
+            }
+        );
+    };
+
+    (@(make_gen_item_macro) $name: ident, $($rule: tt)*) => {
+        macro_rules! $name {
+            $($rule)*
+        }
+    };
+}
+
+pub(crate) use impl_multiple;
+
 mod sealed
 {
     pub trait Sealed {}