Add templates for python derivation.nix and default.nix

Remove poetryshell template, but keep poetry2nix template for cases I
still want it

templates

@@ -207,7 +207,7 @@ nix-mode
 
 (pkgs "pkgs = import " (p "<nixpkgs>") " {};")
 (poetry2nix "poetry2nix = (builtins.getFlake \"github:nix-community/poetry2nix\").lib.mkPoetry2Nix {inherit pkgs;};")
-(pythonshell "let" n
+(pyshell "let" n
          > "pkgs = import " (p "<nixpkgs>") " {};" n
          > "in pkgs.mkShellNoCC {" n
          > "packages = with pkgs; [" n
@@ -219,25 +219,19 @@ nix-mode
          > "export LD_LIBRARY_PATH=${pkgs.stdenv.cc.cc.lib}/lib:${pkgs.zlib}/lib" n
          > "'';" n
          > "}")
-(poetryshell "# See https://github.com/nix-community/poetry2nix/blob/master/docs/edgecases.md#cases" n
-             "# for edgecases like setuptools not found" n
-             "let" n
+(pyderivation "{ buildPythonPackage, " (p "poetry-core" build) ", " (p "" dependencies) "}:" n
+              "buildPythonPackage {" n
+              > "pname = \"" (p "package") "\";" n
+              > "version = \"" (p "0.1.0") "\";" n
+              > "src = ./.;" n
+              > "build-system = [ " (s build)" ];" n
+              > "dependencies = [ " (string-replace "," "" dependencies) " ];" n
+              > "}")
+(pydefault "let" n
            > "pkgs = import " (p "<nixpkgs>") " { };" n
-             > "poetry2nix = (builtins.getFlake \"github:nix-community/poetry2nix\").lib.mkPoetry2Nix {inherit pkgs;};" n
-             > "poetryEnv = let " n
-             > "projectDir = " (p "./.") ";" n
-             > "in (poetry2nix.mkPoetryEnv {" n
-             > "inherit projectDir;" n
-             > "overrides = poetry2nix.defaultPoetryOverrides;" n
-             > "python = " (p "pkgs.python3Full") ";" n
-             > "editablePackageSources = {" (p "package") "= projectDir;};" n
-             > "extraPackages = (ps: [" q  "]);" n
-             > "preferWheels = true;" n
-             > "groups = [\"dev\"];" n
-             > "extras = [\"*\"];" n
-             > "});" n
+           > "python3 = " (p "pkgs.python3") ";" n
            "in" n
-             > "poetryEnv.env")
+           > "python3.pkgs.callPackage ./derivation.nix {" q "}")
 
 envrc-file-mode