* Move the implementation of the ‘derivation’ primop into a separate

  file.

2 files changed, 32 insertions, 1 deletions

diff --git a/corepkgs/Makefile.am b/corepkgs/Makefile.am
index 86d7027ed06e..a8de601657b1 100644
--- a/corepkgs/Makefile.am
+++ b/corepkgs/Makefile.am
@@ -1,6 +1,6 @@
 all-local: config.nix
 
-files = nar.nix buildenv.nix buildenv.pl unpack-channel.nix unpack-channel.sh
+files = nar.nix buildenv.nix buildenv.pl unpack-channel.nix unpack-channel.sh derivation.nix
 
 install-exec-local:
 	$(INSTALL) -d $(DESTDIR)$(datadir)/nix/corepkgs
diff --git a/corepkgs/derivation.nix b/corepkgs/derivation.nix
new file mode 100644
index 000000000000..0e16ad6fa300
--- /dev/null
+++ b/corepkgs/derivation.nix
@@ -0,0 +1,31 @@
+attrs:
+
+let
+
+  strict = derivationStrict attrs;
+  
+  attrValues = attrs:
+    map (name: builtins.getAttr name attrs) (builtins.attrNames attrs);
+    
+  outputToAttrListElement = output:
+    { name = output;
+      value = attrs // {
+        outPath = builtins.getAttr (output + "Path") strict;
+        drvPath = strict.drvPath;
+        type = "derivation";
+        currentOutput = output;
+      } // outputsAttrs // { all = allList; };
+    };
+    
+  outputsList =
+    if attrs ? outputs
+    then map outputToAttrListElement attrs.outputs
+    else [ (outputToAttrListElement "out") ];
+    
+  outputsAttrs = builtins.listToAttrs outputsList;
+  
+  allList = attrValues outputsAttrs;
+  
+  head = if attrs ? outputs then builtins.head attrs.outputs else "out";
+  
+in builtins.getAttr head outputsAttrs