Add snack run and fixup script

default.nix

@@ -1,16 +1,48 @@
-{ pkgs ? import <nixpkgs> {} }:
+{ pkgs ? import ./nix {} }:
 
 { snack-lib = import ./snack/default.nix { inherit pkgs; };
   snack-exe = pkgs.writeScriptBin "snack"
       ''
-        set -e
-        case $1 in
+        set -euo pipefail
+
+        SNACK_NIX=snack.nix
+
+        while [[ $# -gt 0 ]]
+        do
+        key="$1"
+
+        case $key in
+            -f|--snack-nix)
+            SNACK_NIX="$2"
+            shift
+            shift
+            ;;
+            run|build|ghci)
+            COMMAND="$1"
+            shift # past argument
+            ;;
+            *)    # unknown option
+            echo "unknown option: $1"
+            exit 1
+            ;;
+        esac
+        done
+        echo "snack nix: $SNACK_NIX"
+        echo "command: $COMMAND"
+
+        case $COMMAND in
           build)
-            ${pkgs.nix}/bin/nix-build snack.nix
+            ${pkgs.nix}/bin/nix-build --no-out-link -A build $SNACK_NIX
             ;;
           ghci)
-            res=$(${pkgs.nix}/bin/nix-build -A ghci snack.nix)
+            res=$(${pkgs.nix}/bin/nix-build --no-out-link -A ghci $SNACK_NIX)
             $res/bin/ghci
+            ;;
+          run)
+            res=$(${pkgs.nix}/bin/nix-build --no-out-link -A build $SNACK_NIX)
+            echo "running $res"
+            $res/out
+            ;;
         esac
       '';
 }

nix/default.nix

@@ -2,19 +2,6 @@
 import (import nixpkgs) {
   config = { allowUnfree = true; };
   overlays = [
-    (self: super: { snack-lib = import ../snack {};} )
-    (self: super: { snack-lib-with = extra: import ../snack extra;} )
-    (self: super: { snack = self.writeScriptBin "snack"
-      ''
-        set -e
-        case $1 in
-          build)
-            ${self.nix}/bin/nix-build snack.nix
-            ;;
-          ghci)
-            res=$(${self.nix}/bin/nix-build -A ghci snack.nix)
-            $res/bin/ghci
-        esac
-      ''; })
+    (self: super: { snack = import ../. {}; })
   ];
 }

script/test

@@ -1,7 +1,7 @@
 #!/usr/bin/env nix-shell
 #!nix-shell -i bash
 #!nix-shell -I nixpkgs=./nix
-#!nix-shell -p snack
+#!nix-shell -p snack.snack-exe
 #!nix-shell --pure
 # vim: ft=sh sw=2 et
 
@@ -15,8 +15,8 @@ pushd tests/template-haskell
 snack build
 popd
 
-pushd tests/template-haskell-2/code
-snack build
+pushd tests/template-haskell-2
+snack build -f code/snack.nix
 popd
 
 pushd tests/template-haskell-3

tests/packages/snack.nix

@@ -1,6 +1,6 @@
 let
   pkgs = import ../../nix {};
-  snack = pkgs.snack-lib;
+  snack = pkgs.snack.snack-lib;
 in
   snack.executable
     { main = "Foo";

tests/template-haskell-2/code/snack.nix

@@ -1,6 +1,6 @@
 let
   pkgs = import ../../../nix {};
-  snack = pkgs.snack-lib;
+  snack = pkgs.snack.snack-lib;
 in
   snack.executable
     { main = "Main";

tests/template-haskell-3/snack.nix

@@ -1,13 +1,11 @@
 let
   pkgs = import ../../nix {};
-  snack = pkgs.snack-lib;
+  snack = pkgs.snack.snack-lib;
 in
   snack.executable
     { main = "Main";
       src = ./.;
       dependencies = ["file-embed"];
       extra-files =
-        # "assets/foo.txt", which is just
-        # filterSource (p == "assets/foo.txt") ./.
         (modName: if modName == "Main" then [ "assets/foo.txt" ] else []);
     }

tests/template-haskell/snack.nix

@@ -1,6 +1,6 @@
 let
   pkgs = import ../../nix {};
-  snack = pkgs.snack-lib;
+  snack = pkgs.snack.snack-lib;
 in
   snack.executable
     { main = "Main";