lib: implement `setPrio`

For when `hiPrio` and `lowPrio` are not enough.

1 files changed, 6 insertions, 5 deletions

diff --git a/lib/meta.nix b/lib/meta.nix
index 199030c103a..2e83c4247dd 100644
--- a/lib/meta.nix
+++ b/lib/meta.nix
@@ -41,16 +41,18 @@ rec {
     let x = builtins.parseDrvName name; in "${x.name}-${suffix}-${x.version}");
 
 
-  /* Apply a function to each derivation and only to derivations in an attrset
+  /* Apply a function to each derivation and only to derivations in an attrset.
   */
   mapDerivationAttrset = f: set: lib.mapAttrs (name: pkg: if lib.isDerivation pkg then (f pkg) else pkg) set;
 
+  /* Set the nix-env priority of the package.
+  */
+  setPrio = priority: addMetaAttrs { inherit priority; };
 
   /* Decrease the nix-env priority of the package, i.e., other
      versions/variants of the package will be preferred.
   */
-  lowPrio = drv: addMetaAttrs { priority = 10; } drv;
-
+  lowPrio = setPrio 10;
 
   /* Apply lowPrio to an attrset with derivations
   */
@@ -60,8 +62,7 @@ rec {
   /* Increase the nix-env priority of the package, i.e., this
      version/variant of the package will be preferred.
   */
-  hiPrio = drv: addMetaAttrs { priority = -10; } drv;
-
+  hiPrio = setPrio (-10);
 
   /* Apply hiPrio to an attrset with derivations
   */