Function types (#6891)

* Change Fn to fn for function types

Signed-off-by: Nick Cameron <nrc@ncameron.org>

* Support args and return types in function types

Signed-off-by: Nick Cameron <nrc@ncameron.org>

* Use fancy function types in the docs

Signed-off-by: Nick Cameron <nrc@ncameron.org>

---------

Signed-off-by: Nick Cameron <nrc@ncameron.org>

docs/kcl-std/functions/std-array-map.md

@@ -10,7 +10,7 @@ Apply a function to every element of a list.
 ```kcl
 map(
   @array: [any],
-  f: Fn,
+  f: fn(any): any,
 ): [any]
 ```
 
@@ -22,7 +22,7 @@ Given a list like `[a, b, c]`, and a function like `f`, returns
 | Name | Type | Description | Required |
 |----------|------|-------------|----------|
 | `array` | [`[any]`](/docs/kcl-std/types/std-types-any) | Input array. The output array is this input array, but every element has had the function `f` run on it. | Yes |
-| `f` | [`Fn`](/docs/kcl-std/types/std-types-Fn) | A function. The output array is just the input array, but `f` has been run on every item. | Yes |
+| `f` | [`fn(any): any`](/docs/kcl-std/types/std-types-fn) | A function. The output array is just the input array, but `f` has been run on every item. | Yes |
 
 ### Returns
 

docs/kcl-std/functions/std-array-reduce.md

@@ -11,7 +11,7 @@ layout: manual
 reduce(
   @array: [any],
   initial: any,
-  f: Fn,
+  f: fn(any, accum: any): any,
 ): [any]
 ```
 
@@ -24,7 +24,7 @@ using the previous value and the element.
 |----------|------|-------------|----------|
 | `array` | [`[any]`](/docs/kcl-std/types/std-types-any) | Each element of this array gets run through the function `f`, combined with the previous output from `f`, and then used for the next run. | Yes |
 | `initial` | [`any`](/docs/kcl-std/types/std-types-any) | The first time `f` is run, it will be called with the first item of `array` and this initial starting value. | Yes |
-| `f` | [`Fn`](/docs/kcl-std/types/std-types-Fn) | Run once per item in the input `array`. This function takes an item from the array, and the previous output from `f` (or `initial` on the very first run). The final time `f` is run, its output is returned as the final output from `reduce`. | Yes |
+| `f` | [`fn(any, accum: any): any`](/docs/kcl-std/types/std-types-fn) | Run once per item in the input `array`. This function takes an item from the array, and the previous output from `f` (or `initial` on the very first run). The final time `f` is run, its output is returned as the final output from `reduce`. | Yes |
 
 ### Returns
 

docs/kcl-std/index.md

@@ -140,13 +140,13 @@ See also the [types overview](/docs/kcl-lang/types)
 
 * [**Primitive types**](/docs/kcl-lang/types)
   * [`End`](/docs/kcl-lang/types#End)
-  * [`Fn`](/docs/kcl-std/types/std-types-Fn)
   * [`ImportedGeometry`](/docs/kcl-std/types/std-types-ImportedGeometry)
   * [`Start`](/docs/kcl-lang/types#Start)
   * [`TagDeclarator`](/docs/kcl-lang/types#TagDeclarator)
   * [`TagIdentifier`](/docs/kcl-lang/types#TagIdentifier)
   * [`any`](/docs/kcl-std/types/std-types-any)
   * [`bool`](/docs/kcl-std/types/std-types-bool)
+  * [`fn`](/docs/kcl-std/types/std-types-fn)
   * [`number`](/docs/kcl-std/types/std-types-number)
   * [`string`](/docs/kcl-std/types/std-types-string)
   * [`tag`](/docs/kcl-std/types/std-types-tag)

docs/kcl-std/modules/std-types.md

@@ -17,7 +17,6 @@ Types can (optionally) be used to describe a function's arguments and returned v
 * [`Axis3d`](/docs/kcl-std/types/std-types-Axis3d)
 * [`Edge`](/docs/kcl-std/types/std-types-Edge)
 * [`Face`](/docs/kcl-std/types/std-types-Face)
-* [`Fn`](/docs/kcl-std/types/std-types-Fn)
 * [`Helix`](/docs/kcl-std/types/std-types-Helix)
 * [`ImportedGeometry`](/docs/kcl-std/types/std-types-ImportedGeometry)
 * [`Plane`](/docs/kcl-std/types/std-types-Plane)
@@ -27,6 +26,7 @@ Types can (optionally) be used to describe a function's arguments and returned v
 * [`Solid`](/docs/kcl-std/types/std-types-Solid)
 * [`any`](/docs/kcl-std/types/std-types-any)
 * [`bool`](/docs/kcl-std/types/std-types-bool)
+* [`fn`](/docs/kcl-std/types/std-types-fn)
 * [`number`](/docs/kcl-std/types/std-types-number)
 * [`string`](/docs/kcl-std/types/std-types-string)
 * [`tag`](/docs/kcl-std/types/std-types-tag)

docs/kcl-std/types/std-types-fn.md

@@ -1,5 +1,5 @@
 ---
-title: "Fn"
+title: "fn"
 subtitle: "Type in std::types"
 excerpt: "The type of any function in KCL."
 layout: manual