mirror of
https://github.com/NixOS/nixpkgs.git
synced 2024-11-29 10:23:29 +00:00
Merge pull request #312393 from hsjobeki/doc/lib-fixedpoints
doc: migrate lib.fixedPoints to doc-comment format
This commit is contained in:
commit
43e364791b
@ -1,6 +1,6 @@
|
||||
{ lib, ... }:
|
||||
rec {
|
||||
/*
|
||||
/**
|
||||
`fix f` computes the fixed point of the given function `f`. In other words, the return value is `x` in `x = f x`.
|
||||
|
||||
`f` must be a lazy function.
|
||||
@ -63,27 +63,52 @@ rec {
|
||||
See [`extends`](#function-library-lib.fixedPoints.extends) for an example use case.
|
||||
There `self` is also often called `final`.
|
||||
|
||||
Type: fix :: (a -> a) -> a
|
||||
|
||||
Example:
|
||||
# Inputs
|
||||
|
||||
`f`
|
||||
|
||||
: 1\. Function argument
|
||||
|
||||
# Type
|
||||
|
||||
```
|
||||
fix :: (a -> a) -> a
|
||||
```
|
||||
|
||||
# Examples
|
||||
:::{.example}
|
||||
## `lib.fixedPoints.fix` usage example
|
||||
|
||||
```nix
|
||||
fix (self: { foo = "foo"; bar = "bar"; foobar = self.foo + self.bar; })
|
||||
=> { bar = "bar"; foo = "foo"; foobar = "foobar"; }
|
||||
|
||||
fix (self: [ 1 2 (elemAt self 0 + elemAt self 1) ])
|
||||
=> [ 1 2 3 ]
|
||||
```
|
||||
|
||||
:::
|
||||
*/
|
||||
fix = f: let x = f x; in x;
|
||||
|
||||
/*
|
||||
/**
|
||||
A variant of `fix` that records the original recursive attribute set in the
|
||||
result, in an attribute named `__unfix__`.
|
||||
|
||||
This is useful in combination with the `extends` function to
|
||||
implement deep overriding.
|
||||
|
||||
|
||||
# Inputs
|
||||
|
||||
`f`
|
||||
|
||||
: 1\. Function argument
|
||||
*/
|
||||
fix' = f: let x = f x // { __unfix__ = f; }; in x;
|
||||
|
||||
/*
|
||||
/**
|
||||
Return the fixpoint that `f` converges to when called iteratively, starting
|
||||
with the input `x`.
|
||||
|
||||
@ -92,7 +117,22 @@ rec {
|
||||
0
|
||||
```
|
||||
|
||||
Type: (a -> a) -> a -> a
|
||||
|
||||
# Inputs
|
||||
|
||||
`f`
|
||||
|
||||
: 1\. Function argument
|
||||
|
||||
`x`
|
||||
|
||||
: 2\. Function argument
|
||||
|
||||
# Type
|
||||
|
||||
```
|
||||
(a -> a) -> a -> a
|
||||
```
|
||||
*/
|
||||
converge = f: x:
|
||||
let
|
||||
@ -102,7 +142,7 @@ rec {
|
||||
then x
|
||||
else converge f x';
|
||||
|
||||
/*
|
||||
/**
|
||||
Extend a function using an overlay.
|
||||
|
||||
Overlays allow modifying and extending fixed-point functions, specifically ones returning attribute sets.
|
||||
@ -217,12 +257,30 @@ rec {
|
||||
```
|
||||
:::
|
||||
|
||||
Type:
|
||||
|
||||
# Inputs
|
||||
|
||||
`overlay`
|
||||
|
||||
: The overlay to apply to the fixed-point function
|
||||
|
||||
`f`
|
||||
|
||||
: The fixed-point function
|
||||
|
||||
# Type
|
||||
|
||||
```
|
||||
extends :: (Attrs -> Attrs -> Attrs) # The overlay to apply to the fixed-point function
|
||||
-> (Attrs -> Attrs) # A fixed-point function
|
||||
-> (Attrs -> Attrs) # The resulting fixed-point function
|
||||
```
|
||||
|
||||
Example:
|
||||
# Examples
|
||||
:::{.example}
|
||||
## `lib.fixedPoints.extends` usage example
|
||||
|
||||
```nix
|
||||
f = final: { a = 1; b = final.a + 2; }
|
||||
|
||||
fix f
|
||||
@ -236,13 +294,13 @@ rec {
|
||||
|
||||
fix (extends (final: prev: { c = final.a + final.b; }) f)
|
||||
=> { a = 1; b = 3; c = 4; }
|
||||
```
|
||||
|
||||
:::
|
||||
*/
|
||||
extends =
|
||||
# The overlay to apply to the fixed-point function
|
||||
overlay:
|
||||
# The fixed-point function
|
||||
f:
|
||||
# Wrap with parenthesis to prevent nixdoc from rendering the `final` argument in the documentation
|
||||
# The result should be thought of as a function, the argument of that function is not an argument to `extends` itself
|
||||
(
|
||||
final:
|
||||
@ -252,10 +310,29 @@ rec {
|
||||
prev // overlay final prev
|
||||
);
|
||||
|
||||
/*
|
||||
/**
|
||||
Compose two extending functions of the type expected by 'extends'
|
||||
into one where changes made in the first are available in the
|
||||
'super' of the second
|
||||
|
||||
|
||||
# Inputs
|
||||
|
||||
`f`
|
||||
|
||||
: 1\. Function argument
|
||||
|
||||
`g`
|
||||
|
||||
: 2\. Function argument
|
||||
|
||||
`final`
|
||||
|
||||
: 3\. Function argument
|
||||
|
||||
`prev`
|
||||
|
||||
: 4\. Function argument
|
||||
*/
|
||||
composeExtensions =
|
||||
f: g: final: prev:
|
||||
@ -263,7 +340,7 @@ rec {
|
||||
prev' = prev // fApplied;
|
||||
in fApplied // g final prev';
|
||||
|
||||
/*
|
||||
/**
|
||||
Compose several extending functions of the type expected by 'extends' into
|
||||
one where changes made in preceding functions are made available to
|
||||
subsequent ones.
|
||||
@ -276,7 +353,7 @@ rec {
|
||||
composeManyExtensions =
|
||||
lib.foldr (x: y: composeExtensions x y) (final: prev: {});
|
||||
|
||||
/*
|
||||
/**
|
||||
Create an overridable, recursive attribute set. For example:
|
||||
|
||||
```
|
||||
@ -298,9 +375,20 @@ rec {
|
||||
*/
|
||||
makeExtensible = makeExtensibleWithCustomName "extend";
|
||||
|
||||
/*
|
||||
/**
|
||||
Same as `makeExtensible` but the name of the extending attribute is
|
||||
customized.
|
||||
|
||||
|
||||
# Inputs
|
||||
|
||||
`extenderName`
|
||||
|
||||
: 1\. Function argument
|
||||
|
||||
`rattrs`
|
||||
|
||||
: 2\. Function argument
|
||||
*/
|
||||
makeExtensibleWithCustomName = extenderName: rattrs:
|
||||
fix' (self: (rattrs self) // {
|
||||
|
Loading…
Reference in New Issue
Block a user