diff options
| -rw-r--r-- | CHANGELOG.md | 3 | ||||
| -rw-r--r-- | README.md | 2 | ||||
| -rw-r--r-- | src/ffi.js | 20 | ||||
| -rw-r--r-- | src/gleam/javascript.gleam | 18 | ||||
| -rw-r--r-- | test/gleam/javascript_test.gleam | 8 |
5 files changed, 50 insertions, 1 deletions
diff --git a/CHANGELOG.md b/CHANGELOG.md index 1ce8036..be86f89 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -3,7 +3,8 @@ ## Unreleased - The `javascript` module was created with the `TypeOf`, and `Symbol` types, and - `find_symbol`, and `type_of` functions. + `find_symbol`, `make_reference`, `set_reference`, `update_reference`, + `dereference` and `type_of` functions. - The `javascript/array` module was created with the `Array(element)` type and `to_list`, `from_list`, `map`, `fold`, `fold_right`, `get`, and `length` functions. @@ -5,5 +5,7 @@ Extra code for when running on JavaScript ## Features - Arrays +- Mutable references +- Promises - Symbols - `typeof` @@ -98,3 +98,23 @@ export function map_promise(promise, fn) { export function rescue(promise, fn) { return promise.catch((error) => fn(error)); } + +class Reference { + constructor(value) { + this.value = value; + } +} + +export function dereference(reference) { + return reference.value; +} + +export function make_reference(value) { + return new Reference(value); +} + +export function set_reference(ref, value) { + let previous = ref.value; + ref.value = value; + return previous; +} diff --git a/src/gleam/javascript.gleam b/src/gleam/javascript.gleam index 590dece..f4af2ed 100644 --- a/src/gleam/javascript.gleam +++ b/src/gleam/javascript.gleam @@ -17,3 +17,21 @@ pub external fn type_of(value) -> TypeOf = pub external fn get_symbol(String) -> Symbol = "../ffi.js" "get_symbol" + +pub external type Reference(value) + +pub external fn dereference(Reference(a)) -> a = + "../ffi.js" "dereference" + +pub external fn set_reference(Reference(a), a) -> a = + "../ffi.js" "set_reference" + +pub external fn make_reference(a) -> Reference(a) = + "../ffi.js" "make_reference" + +// returns the old value +pub fn update_reference(ref: Reference(a), f: fn(a) -> a) -> a { + let value = dereference(ref) + set_reference(ref, f(value)) + value +} diff --git a/test/gleam/javascript_test.gleam b/test/gleam/javascript_test.gleam index 81477d8..4b0fc9e 100644 --- a/test/gleam/javascript_test.gleam +++ b/test/gleam/javascript_test.gleam @@ -23,3 +23,11 @@ pub fn find_symbol_test() { assert True = javascript.get_symbol("Gleam") == javascript.get_symbol("Gleam") assert False = javascript.get_symbol("Gleam") == javascript.get_symbol("Lua") } + +pub fn reference_test() { + let ref = javascript.make_reference(1) + assert 1 = javascript.update_reference(ref, fn(a) { a + 1 }) + assert 2 = javascript.dereference(ref) + assert 2 = javascript.set_reference(ref, 3) + assert 3 = javascript.dereference(ref) +} |