From 8c8363fe993e20f2209173a9deae59e9fd02b574 Mon Sep 17 00:00:00 2001
From: wandalen <wandalen.me@gmail.com>
Date: Wed, 27 Mar 2024 14:34:21 +0200
Subject: [PATCH] experimenting

---
 module/core/former/src/axiomatic.rs           | 21 ++++++++++++++++++-
 module/core/former/src/vector.rs              |  9 ++++----
 .../inc/former_tests/container_former_vec.rs  | 12 ++++++++---
 3 files changed, 33 insertions(+), 9 deletions(-)

diff --git a/module/core/former/src/axiomatic.rs b/module/core/former/src/axiomatic.rs
index c180edef24..879fa3ec60 100644
--- a/module/core/former/src/axiomatic.rs
+++ b/module/core/former/src/axiomatic.rs
@@ -39,7 +39,7 @@ pub trait FormerDefinition : Sized
 /// - `Storage`: The type of the container being processed.
 /// - `Context`: The type of the context that might be altered or returned upon completion.
 
-// xxx2 : contunue. try
+// xxx2 : continue. try
 // pub trait FormingEnd< Definition : FormerDefinitionTypes > : Default
 pub trait FormingEnd< Definition : FormerDefinitionTypes >
 {
@@ -105,6 +105,25 @@ where
   }
 }
 
+// xxx : improve description
+/// Use `NoEnd` to fill parameter FormingEnd in struct where parameter exists, but it is not needed.
+/// It might be needed if the same struct is used as `FormerDefinitionTypes` and as `FormerDefinition`, because the first one does not have information aboud End function.
+/// Similar logic which `std::marker::PhantomData` has behind.
+#[ derive( Debug, Default ) ]
+pub struct NoEnd;
+
+impl< Definition > FormingEnd< Definition >
+for NoEnd
+where
+  Definition : FormerDefinitionTypes< Context = () >,
+{
+  #[ inline( always ) ]
+  fn call( &self, storage : Definition::Storage, _context : core::option::Option< () > ) -> Definition::Formed
+  {
+    unreachable!();
+  }
+}
+
 /// A wrapper around a closure to be used as a `FormingEnd`.
 ///
 /// This struct allows for dynamic dispatch of a closure that matches the
diff --git a/module/core/former/src/vector.rs b/module/core/former/src/vector.rs
index da59e7e122..c170e12368 100644
--- a/module/core/former/src/vector.rs
+++ b/module/core/former/src/vector.rs
@@ -51,7 +51,7 @@ pub struct VectorDefinition< E, Context = (), Formed = Vec< E >, End = ReturnSto
 
 impl< E, Context, Formed > FormerDefinitionTypes
 // for VectorDefinition< E, Context, Formed >
-for VectorDefinition< E, Context, Formed, ReturnStorage >
+for VectorDefinition< E, Context, Formed, NoEnd >
 // for VectorDefinition< E, Context, Formed, End >
 // where
   // End : FormingEnd< Self >,
@@ -64,9 +64,9 @@ for VectorDefinition< E, Context, Formed, ReturnStorage >
 impl< E, Context, Formed, End > FormerDefinition
 for VectorDefinition< E, Context, Formed, End >
 where
-  End : FormingEnd< VectorDefinition< E, Context, Formed, ReturnStorage > >,
+  End : FormingEnd< VectorDefinition< E, Context, Formed, NoEnd > >,
 {
-  type Types = VectorDefinition< E, Context, Formed, ReturnStorage >;
+  type Types = VectorDefinition< E, Context, Formed, NoEnd >;
   type End = End;
 }
 
@@ -99,7 +99,6 @@ impl< E > VecExt< E > for Vec< E >
 
 mod sealed
 {
-  use super::Vec;
   pub trait Sealed {}
-  impl< E > Sealed for Vec< E > {}
+  impl< E > Sealed for super::Vec< E > {}
 }
diff --git a/module/core/former/tests/inc/former_tests/container_former_vec.rs b/module/core/former/tests/inc/former_tests/container_former_vec.rs
index 048af90f1f..7aeb920776 100644
--- a/module/core/former/tests/inc/former_tests/container_former_vec.rs
+++ b/module/core/former/tests/inc/former_tests/container_former_vec.rs
@@ -4,6 +4,8 @@ use super::*;
 #[ allow( unused_imports ) ]
 use collection_tools::Vec;
 
+//
+
 #[ test ]
 fn definitions()
 {
@@ -28,9 +30,13 @@ fn definitions()
   }
 
   // f1( former::VectorDefinition::< String, () >::default() );
-  f2( former::VectorDefinition::< String, (), Vec< String >, the_module::ReturnStorage >::default() );
-  f3::< former::VectorDefinition< String, (), Vec< String >, the_module::ReturnStorage >, the_module::ReturnStorage >( the_module::ReturnStorage );
-  f3::< < former::VectorDefinition< String, (), Vec< String >, the_module::ReturnStorage > as the_module::FormerDefinition >::Types, the_module::ReturnStorage >( the_module::ReturnStorage );
+  f2( former::VectorDefinition::< String, (), Vec< String >, the_module::NoEnd >::default() );
+  f3::< former::VectorDefinition< String, (), Vec< String >, the_module::NoEnd >, the_module::ReturnStorage >( the_module::ReturnStorage );
+  f3::< < former::VectorDefinition< String, (), Vec< String >, the_module::NoEnd > as the_module::FormerDefinition >::Types, the_module::ReturnStorage >( the_module::ReturnStorage );
+
+  // assert_eq!( 0, 1 );
+
+  let vec : Vec< String > = vec![ "a".into(), "b".into(), "c".into() ];
 
 }