diff options
| -rw-r--r-- | lib/fixed-points.nix | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/lib/fixed-points.nix b/lib/fixed-points.nix index a11b5a6f4bdc..5039a45cc3f1 100644 --- a/lib/fixed-points.nix +++ b/lib/fixed-points.nix @@ -71,8 +71,19 @@ rec { # Same as `makeExtensible` but the name of the extending attribute is # customized. - makeExtensibleWithCustomName = extenderName: rattrs: - fix' rattrs // { - ${extenderName} = f: makeExtensibleWithCustomName extenderName (extends f rattrs); - }; + makeExtensibleWithCustomName = extenderName: makeExtensibleWithInterface + (fixedPoint: extend: fixedPoint // { ${extenderName} = extend; }); + + # Similar to `makeExtensible`, but expects you to implement the + # final interface for the result. Specifically, it takes an extra + # argument: a function that takes the final result and the `extend` + # function as arguments, and returns a transformed result + # (preferably one that contains the `extend` function). This is + # mainly useful for getting to choose what to name the `extend` + # function in the resulting attribute set. But it's also useful for + # having an internal structure that extensions can see, but the user + # facing code cannot. + makeExtensibleWithInterface = interface: fext: interface + (fix' fext) + (f: makeExtensibleWithInterface interface (extends f fext)); } |