Skip to content

Show how to use GADTs with inline function type annotations #1103

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 1 commit into from
Sep 5, 2025
Merged

Show how to use GADTs with inline function type annotations #1103

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
50 changes: 25 additions & 25 deletions pages/docs/manual/v11.0.0/generalized-algebraic-data-types.mdx
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -118,13 +118,11 @@ Sometimes, a function should have a different return type based on what you give
```res example
type rec number<_> = Int(int): number<int> | Float(float): number<float>

let add:
type a. (number<a>, number<a>) => a =
(a, b) =>
switch (a, b) {
| (Int(a), Int(b)) => a + b
| (Float(a), Float(b)) => a +. b
}
let add = (type a, x: number<a>, y: number<a>): a =>
switch (x, y) {
| (Int(x), Int(y)) => x + y
| (Float(x), Float(y)) => x +. y
}

let foo = add(Int(1), Int(2))

Expand All @@ -145,26 +143,28 @@ module IfNotFound = {
| DefaultTo('a): t<'a, 'a>
}

let flexible_find:
type a b. (~f: a => bool, array<a>, IfNotFound.t<a, b>) => b =
(~f, arr, ifNotFound) => {
open IfNotFound
switch Array.find(arr, f) {
| None =>
switch ifNotFound {
| Raise => failwith("No matching item found")
| ReturnNone => None
| DefaultTo(x) => x
}
| Some(x) =>
switch ifNotFound {
| ReturnNone => Some(x)
| Raise => x
| DefaultTo(_) => x
}
let flexible_find = (
type a b,
~f: a => bool,
arr: array<a>,
ifNotFound: IfNotFound.t<a, b>,
): b => {
open IfNotFound
switch Array.find(arr, f) {
| None =>
switch ifNotFound {
| Raise => failwith("No matching item found")
| ReturnNone => None
| DefaultTo(x) => x
}
| Some(x) =>
switch ifNotFound {
| ReturnNone => Some(x)
| Raise => x
| DefaultTo(_) => x
}
}

}
```

## Hide and recover Type information Dynamically
Expand Down
50 changes: 25 additions & 25 deletions pages/docs/manual/v12.0.0/generalized-algebraic-data-types.mdx
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -118,13 +118,11 @@ Sometimes, a function should have a different return type based on what you give
```res example
type rec number<_> = Int(int): number<int> | Float(float): number<float>

let add:
type a. (number<a>, number<a>) => a =
(a, b) =>
switch (a, b) {
| (Int(a), Int(b)) => a + b
| (Float(a), Float(b)) => a +. b
}
let add = (type a, x: number<a>, y: number<a>): a =>
switch (x, y) {
| (Int(x), Int(y)) => x + y
| (Float(x), Float(y)) => x +. y
}

let foo = add(Int(1), Int(2))

Expand All @@ -145,26 +143,28 @@ module IfNotFound = {
| DefaultTo('a): t<'a, 'a>
}

let flexible_find:
type a b. (~f: a => bool, array<a>, IfNotFound.t<a, b>) => b =
(~f, arr, ifNotFound) => {
open IfNotFound
switch Array.find(arr, f) {
| None =>
switch ifNotFound {
| Raise => failwith("No matching item found")
| ReturnNone => None
| DefaultTo(x) => x
}
| Some(x) =>
switch ifNotFound {
| ReturnNone => Some(x)
| Raise => x
| DefaultTo(_) => x
}
let flexible_find = (
type a b,
~f: a => bool,
arr: array<a>,
ifNotFound: IfNotFound.t<a, b>,
): b => {
open IfNotFound
switch Array.find(arr, f) {
| None =>
switch ifNotFound {
| Raise => failwith("No matching item found")
| ReturnNone => None
| DefaultTo(x) => x
}
| Some(x) =>
switch ifNotFound {
| ReturnNone => Some(x)
| Raise => x
| DefaultTo(_) => x
}
}

}
```

## Hide and recover Type information Dynamically
Expand Down