Merge request #748 shell.nix: use Haskell notation, explicit attrs

Author: Anton-Latukha

default.nix

@@ -76,8 +76,8 @@
 , executableNamesToShellComplete ? [ "hnix" ]
 
 
-# Include Hoogle into derivation
-, withHoogle  ? true
+# Include Hoogle executable and DB into derivation
+, withHoogle  ? false
 
 
 # Nix by default updates and uses locally configured nixpkgs-unstable channel

shell.nix

@@ -1 +1,7 @@
-{} @ attrs: (import ./. attrs).env
+attrs@{...}:
+let defaultAttrs = {
+  # Defaults are put in this form deliberately. Details: #748
+  withHoogle = true;
+  compiler = "ghc8101";
+};
+in (import ./. (defaultAttrs // attrs)).env