move nix files. test default provider override.

README.md

···
 
 However, for many users, a transposed attribute set, `<aspect>.<class>`, can be more intuitive. It often feels more natural to nest classes within aspects rather than the other way around.
 
-This project provides a small, dependency-free [`transpose`](default.nix) primitive that is powerful enough to implement [cross-aspect dependencies](aspects.nix) for any Nix configuration class. It also includes a [flake-parts module](flakeModule.nix) that transforms `flake.aspects` into `flake.modules`.
+This project provides a small, dependency-free [`transpose`](nix/default.nix) primitive that is powerful enough to implement [cross-aspect dependencies](nix/aspects.nix) for any Nix configuration class. It also includes a [flake-parts module](nix/flakeModule.nix) that transforms `flake.aspects` into `flake.modules`.
 
 <table>
 <tr>
···
 
 ## Usage
 
-### As a Dependency-Free Library (`./default.nix`)
+### As a Dependency-Free Library (`./nix/default.nix`)
 
-The [`transpose`](default.nix) library accepts an optional `emit` function that can be used to ignore items, modify them, or generate multiple items from a single input.
+The [`transpose`](nix/default.nix) library accepts an optional `emit` function that can be used to ignore items, modify them, or generate multiple items from a single input.
 
 ```nix
-let transpose = import ./default.nix { lib = pkgs.lib; }; in
+let transpose = import ./nix/default.nix { lib = pkgs.lib; }; in
 transpose { a.b.c = 1; } # => { b.a.c = 1; }
 ```
 
-This `emit` function is utilized by the [`aspects`](aspects.nix) library (both libraries are independent of flakes) to manage cross-aspect, same-class module dependencies.
+This `emit` function is utilized by the [`aspects`](nix/aspects.nix) library (both libraries are independent of flakes) to manage cross-aspect, same-class module dependencies.
 
 ### As a Dendritic Flake-Parts Module (`flake.aspects` option)
 

checkmate.nix

···
   perSystem =
     { lib, ... }:
     let
-      transpose = import ./. { inherit lib; };
+      transpose = import ./nix { inherit lib; };
 
       mkFlake =
         mod:
···
           {
             systems = [ ];
             imports = [
-              ./flakeModule.nix
+              ./nix/flakeModule.nix
               inputs.flake-parts.flakeModules.modules
               mod
               (fooMod "aspectOne")
···
                 {
                   systems = [ ];
                   imports = [
-                    ./flakeModule.nix
+                    ./nix/flakeModule.nix
                     inputs.flake-parts.flakeModules.modules
                   ];
                 };
···
             expected = [
               "1"
               "mundo"
+            ];
+          in
+          {
+            inherit expr expected;
+          };
+
+        aspects."test override default provider" =
+          let
+            flake = mkFlake {
+              flake.aspects =
+                { aspects, ... }:
+                {
+                  aspectOne.includes = [ (aspects.aspectTwo "hello") ];
+                  aspectOne.classOne = { }; # required for propagation
+
+                  aspectTwo.__functor =
+                    _: message:
+                    { class, aspect-chain }:
+                    { aspect, ... }:
+                    {
+                      classOne.bar = [
+                        aspect.name
+                        message
+                        class
+                      ] ++ aspect-chain;
+                    };
+                  aspectTwo.classOne.bar = [ "itself not included" ];
+                };
+            };
+
+            expr = (evalMod "classOne" flake.modules.classOne.aspectOne).bar;
+            expected = [
+              "<function body>"
+              "hello"
+              "classOne"
+              "aspectOne"
             ];
           in
           {

flake.nix

···
 {
   outputs = _: {
-    __functor = _: import ./.;
-    flakeModule = ./flakeModule.nix;
+    __functor = _: import ./nix;
+    flakeModule = ./nix/flakeModule.nix;
   };
 }