Port fixed-point.nix

Function/composeExtensions.dhall

@@ -0,0 +1,18 @@
+λ(nix : ../NixPrelude.dhall) →
+  let Set = ../Set/Type.dhall
+
+  let Set/mergeAttrs = ../Set/mergeAttrs.dhall nix
+
+  let composeExtensions
+      : (Set → Set → Set) → (Set → Set → Set) → Set → Set → Set
+      = λ(f : Set → Set → Set) →
+        λ(g : Set → Set → Set) →
+        λ(final : Set) →
+        λ(prev : Set) →
+          let fApplied = f final prev
+
+          let prevp = Set/mergeAttrs prev fApplied
+
+          in  Set/mergeAttrs fApplied (g final prevp)
+
+  in  composeExtensions

Function/composeManyExtensions.dhall

@@ -0,0 +1,24 @@
+λ(nix : ../NixPrelude.dhall) →
+  let Any = ../Any/Type.dhall
+
+  let Set = ../Set/Type.dhall
+
+  let composeExtensions = ./composeExtensions.dhall nix
+
+  let Set/toSet = ../Set/toSet.dhall nix
+
+  let Map =
+        https://prelude.dhall-lang.org/Map/Type.dhall
+          sha256:210c7a9eba71efbb0f7a66b3dcf8b9d3976ffc2bc0e907aadfb6aa29c333e8ed
+
+  let composeManyExtensions
+      : List (Set → Set → Set) → Set → Set → Set
+      = λ(list : List (Set → Set → Set)) →
+          List/fold
+            (Set → Set → Set)
+            list
+            (Set → Set → Set)
+            composeExtensions
+            (λ(final : Set) → λ(prev : Set) → Set/toSet Any ([] : Map Text Any))
+
+  in  composeManyExtensions

Function/converge.dhall

@@ -0,0 +1,34 @@
+λ(nix : ../NixPrelude.dhall) →
+  let Any = ../Any/Type.dhall
+
+  let Any/toAny = ../Any/toAny.dhall nix
+
+  let Any/toTypeUnchecked = ../Any/toTypeUnchecked.dhall nix
+
+  let Any/equal = ../Any/equal.dhall nix
+
+  in  λ(t : Type) →
+        let FunctionType = λ(x : Type) → x → (t → t) → t → t
+
+        let function =
+              λ(function : FunctionType Any) →
+                let functionArgs =
+                      Any/toTypeUnchecked
+                        (FunctionType (FunctionType Any))
+                        (Any/toAny (FunctionType Any) function)
+                        function
+
+                in  λ(f : t → t) →
+                    λ(x : t) →
+                      let xp = f x
+
+                      in  if    Any/equal (Any/toAny t xp) (Any/toAny t x)
+                          then  x
+                          else  functionArgs f xp
+
+        let functionErased =
+              Any/toTypeUnchecked
+                (FunctionType Any)
+                (Any/toAny (FunctionType (FunctionType Any)) function)
+
+        in  function functionErased

Function/extends.dhall

@@ -0,0 +1,13 @@
+λ(nix : ../NixPrelude.dhall) →
+  let Set = ../Set/Type.dhall
+
+  let Set/mergeAttrs = ../Set/mergeAttrs.dhall nix
+
+  let extends
+      : (Set → Set → Set) → (Set → Set) → Set → Set
+      = λ(f : Set → Set → Set) →
+        λ(rattrs : Set → Set) →
+        λ(self : Set) →
+          let super = rattrs self in Set/mergeAttrs super (f super self)
+
+  in  extends

Function/fix.dhall

@@ -0,0 +1,22 @@
+λ(nix : ../NixPrelude.dhall) →
+  let fixSrc = "f: let x = f x; in x"
+
+  let fixSrcp = "f: let x = f x // { __unfix__ = f; }; in x"
+
+  let fixFile = nix.builtins.toFile "fix.nix" fixSrc
+
+  let fixFilep = nix.builtins.toFile "fix.nix" fixSrcp
+
+  let Any/toTypeUnchecked = ../Any/toTypeUnchecked.dhall nix
+
+  let fix
+      : ∀(t : Type) → (t → t) → t
+      = λ(t : Type) →
+          Any/toTypeUnchecked ((t → t) → t) (nix.builtins.import fixFile)
+
+  let fixp
+      : ∀(t : Type) → (t → t) → t
+      = λ(t : Type) →
+          Any/toTypeUnchecked ((t → t) → t) (nix.builtins.import fixFilep)
+
+  in  { fix, fixp }

Function/makeExtensibleWithCustomName.dhall

@@ -0,0 +1,51 @@
+λ(nix : ../NixPrelude.dhall) →
+  let Any = ../Any/Type.dhall
+
+  let Set = ../Set/Type.dhall
+
+  let Any/toAny = ../Any/toAny.dhall nix
+
+  let Any/toTypeUnchecked = ../Any/toTypeUnchecked.dhall nix
+
+  let fixp = (./fix.dhall nix).fixp Set
+
+  let Set/toSet = ../Set/toSet.dhall nix
+
+  let Set/mergeAttrs = ../Set/mergeAttrs.dhall nix
+
+  let extends = ./extends.dhall nix
+
+  let FunctionType = λ(x : Type) → x → Text → (Set → Set) → Set
+
+  let function =
+        λ(function : FunctionType Any) →
+          let functionArgs =
+                Any/toTypeUnchecked
+                  (FunctionType (FunctionType Any))
+                  (Any/toAny (FunctionType Any) function)
+                  function
+
+          in  λ(extenderName : Text) →
+              λ(rattrs : Set → Set) →
+                let extset =
+                      Set/toSet
+                        ((Set → Set → Set) → Set)
+                        [ { mapKey = extenderName
+                          , mapValue =
+                              λ(f : Set → Set → Set) →
+                                functionArgs extenderName (extends f rattrs)
+                          }
+                        ]
+
+                in  Set/mergeAttrs (fixp rattrs) extset
+
+  let functionErased =
+        Any/toTypeUnchecked
+          (FunctionType Any)
+          (Any/toAny (FunctionType (FunctionType Any)) function)
+
+  let makeExtensibleWithCustomName
+      : Text → (Set → Set) → Set
+      = function functionErased
+
+  in  makeExtensibleWithCustomName

Function/package.dhall

@@ -1,8 +1,16 @@
 λ(nix : ../NixPrelude.dhall) →
-  { const = ./const.dhall
+  { composeExtensions = ./composeExtensions.dhall nix
+  , composeManyExtensions = ./composeManyExtensions.dhall nix
+  , const = ./const.dhall
+  , converge = ./converge.dhall nix
   , deepSeq = ./seq.dhall nix
+  , extends = ./extends.dhall nix
+  , fix = (./fix.dhall nix).fix
+  , fixp = (./fix.dhall nix).fixp
   , flip = ./flip.dhall
   , functionArgs = ./functionArgs.dhall nix
+  , makeExtensible = ./makeExtensibleWithCustomName.dhall nix "extend"
+  , makeExtensibleWithCustomName = ./makeExtensibleWithCustomName.dhall nix
   , pipe = ./pipe.dhall
   , setFunctionArgs = ./setFunctionArgs.dhall nix
   , seq = ./seq.dhall nix